food and bioproducts processing 8 9 ( 2 0 1 1 ) 217–233
Contents lists available at ScienceDirect
Food and Bioproducts Processing
journal homepage: www.elsevier.com/locate/fbp
Review
A review of the antioxidant potential of medicinal plant
species
Duduku Krishnaiah ∗ , Rosalam Sarbatly, Rajesh Nithyanandam
Phytochemical Laboratory, Department of Chemical Engineering, School of Engineering and Information Technology, Universiti Malaysia
Sabah, 88999 Kota Kinabalu, Malaysia
a b s t r a c t
Some researchers suggest that two-thirds of the world’s plant species have medicinal value; in particular, many
medicinal plants have great antioxidant potential. Antioxidants reduce the oxidative stress in cells and are therefore
useful in the treatment of many human diseases, including cancer, cardiovascular diseases and inflammatory diseases. This paper reviews the antioxidant potential of extracts from the stems, roots, bark, leaves, fruits and seeds
of several important medicinal species. Synthetic antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxylanisole (BHA) are currently used as food additives, and many plant species have similar antioxidant
potentials as these synthetics. These species include Diospyros abyssinica, Pistacia lentiscus, Geranium sanguineum L.,
Sargentodoxa cuneata Rehd. Et Wils, Polyalthia cerasoides (Roxb.) Bedd, Crataeva nurvala Buch-Ham., Acacia auriculiformis
A. Cunn, Teucrium polium L., Dracocephalum moldavica L., Urtica dioica L., Ficus microcarpa L. fil., Bidens pilosa Linn. Radiata,
Leea indica, the Lamiaceae species, Uncaria tomentosa (Willd.) DC, Salvia officinalis L., Momordica Charantia L., Rheum ribes
L., and Pelargonium endlicherianum. The literature reveals that these natural antioxidants represent a potentially side
effect-free alternative to synthetic antioxidants in the food processing industry and for use in preventive medicine.
© 2010 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
Keywords: Antioxidant; Oxidative stress; Medicinal species; Different countries
Contents
1.
2.
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
An overview of the assay methods used to estimate antioxidant content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1. DPPH method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2. ABTS method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3. ORAC assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.4. PCL assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Abbreviations: ABTS, 2,2′ -azinobis(3-ethylbenzthiazoline-6-sulphonic acid); ATC, ammonium thiocyanate; BHA, butylated hydroxylanisole; BHT, butylated hydroxytoluene; BR, Briggs Rauscher; DAD, diode array detector; DPPH, 1,1-diphenyl-2-picrylhydrazine; FRAP,
ferric reducing antioxidant power; FTC, ferric thiocyanate; FTC, Folin-Ciocalteau; GA, gallic acid; GAE, gallic acid equivalents; GPx,
glutathione peroxidase; HPLC, high performance liquid chromatography; LPO, lipid peroxidation; NBT, nitro blue tetrazolium; ORAC, oxygen radical absorbance capacity; PCL, luminol-photochemiluminescence; PEs, pyrocatechol equivalents; PG, propyl gallate; PMS-NADH,
phenazine methosulfate–nicotinamide adenine dinucleotide-reduced; QEs, quercetin equivalents; Re eq., resorcinol equivalents; ROS,
reactive oxygen species; SOD, superoxide dismutase; TBA, thiobarbituric acid; TEAC, trolox equivalent antioxidant capacity; TFA, total
flavonoids; TFO, total flavonols; TP, total phenols; TPC, total phenolic content; TRAP, total radical-trapping antioxidant potential; WHO,
World Health Organization.
∗
Corresponding author. Tel.: +60 143749743; fax: +60 88320348.
E-mail address: krishna@ums.edu.my (D. Krishnaiah).
Received 12 October 2009; Received in revised form 28 April 2010; Accepted 29 April 2010
0960-3085/$ – see front matter © 2010 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
doi:10.1016/j.fbp.2010.04.008
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3.
4.
1.
food and bioproducts processing 8 9 ( 2 0 1 1 ) 217–233
2.5. -Carotene linoleic acid bleaching assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.6. Reducing power assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.7. NBT assay or the superoxide anion scavenging activity assay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.8. Total flavonoid content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.9. Folin-Ciocalteu method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Medicinal species with high antioxidant potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1. Diospyros abyssinica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2. Pistacia lentiscus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3. Geranium sanguineum L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4. Sargentodoxa cuneata Rehd. Et Wils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.5. Polyalthia cerasoides (Roxb.) Bedd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.6. Crataeva nurvala Buch-Ham . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.7. Acacia auriculiformis A. Cunn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.8. Teucrium polium L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.9. Dracocephalum moldavica L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.10. Urtica dioica L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.11. Ficus microcarpa L. fil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.12. Bidens pilosa Linn. Radiata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.13. Leea indica. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.14. Lamiaceae species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.15. Uncaria tomentosa (Willd.) DC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.16. Salvia officinalis L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.17. Momordica Charantia L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.18. Rheum ribes L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.19. Pelargonium endlicherianum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Introduction
The adverse effects of oxidative stress on human health
have become a serious issue. The World Health Organization (WHO) has estimated that 80% of the earth’s inhabitants
rely on traditional medicine for their primary health care
needs, and most of this therapy involves the use of plant
extracts and their active components (Winston, 1999). Under
stress, our bodies produce more reactive oxygen species (ROS)
(e.g., superoxide anion radicals, hydroxyl radicals and hydrogen peroxide) than enzymatic antioxidants (e.g., superoxide
dismutase (SOD), glutathione peroxidase (GPx), and catalase)
and non-enzymatic antioxidants (e.g., ascorbic acid (vitamin
C), ␣-tocopherol (vitamin E), glutathione, carotenoids, and
flavonoids). This imbalance leads to cell damage (Aruoma,
1998; Lefer and Granger, 2000; Smith et al., 2000; Bhatia et
al., 2003; Peuchant et al., 2004) and health problems (Steer
et al., 2002; Uchida, 2000). A lack of antioxidants, which
can quench the reactive free radicals, facilitates the development of degenerative diseases (Shahidi et al., 1992), including
cardiovascular diseases, cancers (Gerber et al., 2002), neurodegenerative diseases, Alzheimer’s disease (Di Matteo and
Esposito, 2003) and inflammatory diseases (Sreejayan and Rao,
1996). One solution to this problem is to supplement the diet
with antioxidant compounds that are contained in natural
plant sources (Knekt et al., 1996). These natural plant antioxidants can therefore serve as a type of preventive medicine.
Recent reports indicate that there is an inverse relationship between the dietary intake of antioxidant-rich foods and
the incidence of human disease (Sies, 1993). However, synthetic antioxidants, such as butylated hydroxytoluene (BHT)
and butylated hydroxyanisole (BHA), have been widely used
as antioxidants in the food industry and may be responsible
for liver damage and carcinogenesis (Grice, 1988; Wichi, 1986).
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For this reason, interest in the use of natural antioxidants has
increased.
Plants have been the basis of traditional medicines
throughout the world for thousands of years and continue to
provide new remedies to humankind; a great deal of effort has
therefore focused on using available experimental techniques
to identify natural antioxidants from plants. Several authors
have reviewed the beneficial uses of these plant species
(Speroni and Scartezzini, 2000; Matkowski, 2008). Recently, Ali
et al. (2008) reviewed twenty-four medicinal Indian herbs that
have great antioxidant potential. This review covers medicinal
species from a variety of countries (Africa, Algeria, The United
States of America, Australia, Brazil, Bulgaria, China, India,
Iran, Italy, Japan, Malaysia, Poland, Portugal, Thailand and
Turkey). The purpose of this review is to survey the antioxidant
capacity and the total phenolic content of medicinal plants
from around the world and to evaluate potential sources of
natural antioxidants for food and medicinal purposes.
2.
An overview of the assay methods used
to estimate antioxidant content
Antioxidants, including phenolic compounds (e.g., flavonoids,
phenolic acids and tannins), have diverse biological effects,
such as anti-inflammatory, anti-carcinogenic and antiatherosclerotic effects, as a result of their antioxidant activity
(Chung et al., 1998). The antioxidant extracts were evaluated
in terms of their total phenols (TP), total flavonoids (TFA), total
flavonols (TFO), phenolic acids, catechins, lignans and tannins
(Cai et al., 2004; Djeridane et al., 2006).
The antioxidant properties were evaluated using the
following methods: 1,1-diphenyl-2-picrylhydrazine (DPPH)
radical scavenging assay (Blois, 1958; Hatano et al., 1988;
Navarro et al., 1992; Brand-Williams et al., 1995; Cotelle et al.,
food and bioproducts processing 8 9 ( 2 0 1 1 ) 217–233
1996), -carotene linoleic acid bleaching assay (Miller, 1971;
Koleva et al., 2002; Siddhuraju and Becker, 2003), inhibition
of linoleic acid peroxidation (Osawa and Namiki, 1981), ferric reducing antioxidant power (FRAP) (Oyaizu, 1986; Benzie
and Strain, 1996; Benzie and Szeto, 1999), total radical trapping antioxidant potential (TRAP) assay (Lissi et al., 1992;
Krasowska et al., 2001; Leontowicz et al., 2002), oxygen radical
absorbance capacity (ORAC) assay (Ou et al., 2001; Huang et al.,
2002; Silva et al., 2007), 15-lipoxygenase inhibition (Lyckander
and Malterud, 1992), lipid peroxidation (LPO) method (Ohkawa
et al., 1979; Ramos et al., 2001), nitro blue tetrazolium
(NBT) reduction assay or superoxide anion scavenging activity (Beauchamp and Fridovich, 1971; Nishimiki et al., 1972;
Kirby and Schmidt, 1997), hydroxyl radical scavenging activity (Halliwell et al., 1987; Chung et al., 1997; Jodynis-Liebert et
al., 1999) or non-site- and site-specific deoxyribose degradation assay (Halliwell et al., 1987; Arouma et al., 1987; Maulik et
al., 1997), hydrogen peroxide scavenging activity (Ruch et al.,
1989), enzymatic and non-enzymatic in vitro antioxidant assay,
2,2′ -azinobis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS)
radical scavenging method (Rice-Evans and Miller, 1994; Re
et al., 1999; Baltrusaityte et al., 2007), reducing power assay
(Oyaizu, 1986), 50% inhibition of a particular assay (IC50 ), Briggs
Rauscher (BR) method (Cervellati et al., 2002), Trolox equivalent antioxidant capacity (TEAC) method (Salah et al., 1995;
Campos and Lissi, 1996; Rice-Evans et al., 1996; Re et al., 1999),
phenazine methosulfate–nicotinamide adenine dinucleotidereduced (PMS-NADH) system superoxide radical scavenging
(Lau et al., 2002), linoleic acid peroxidation, ammonium thiocyanate (ATC) method (Masude et al., 1992), ferric thiocyanate
(FTC) method, thiobarbituric acid (TBA) method (Mackeen et
al., 2000) and luminol-photochemiluminescence (PCL) assay.
Similarly, the phenolic concentration was determined using
the Folin-Ciocalteau (FTC) method (Singleton and Rossi, 1965;
Slinkard and Singleton, 1977; Singleton et al., 1999), while the
total phenol content (Lamaison et al., 1991; Singleton et al.,
1999; Djeridane et al., 2006), the total flavonoid content (Dai et
al., 1995; Moreno et al., 2000; Sakanaka et al., 2005), the tannin content (Hagerman and Butler, 1978) and the total flavanol
content (Butler et al., 1982) were also determined by known
methods.
Although many methods are available to determine antioxidant activity, it is important to employ a consistent and rapid
method. While each method has its own merits and drawbacks, it has been found that the most common and reliable
methods are the ABTS and DPPH methods; these have been
modified and improved in recent years.
2.1.
DPPH method
The 1,1-diphenyl-2-picrylhydrazine (DPPH) radical scavenging
assay was first described by Blois in 1958 and was later modified slightly by numerous researchers. It is one of the most
extensively used antioxidant assays for plant samples. DPPH
is a stable free radical that reacts with compounds that can
donate a hydrogen atom. This method is based on the scavenging of DPPH through the addition of a radical species or an
antioxidant that decolourizes the DPPH solution. The antioxidant activity is then measured by the decrease in absorption at
515 nm. In this method, a 0.1 mM solution of DPPH in methanol
is prepared, and 4 ml of this solution are added to 1 ml of
the sample solution in methanol at varying concentrations.
Thirty minutes later, the absorbance was measured at 517 nm.
A large decrease in the absorbance of the reaction mixture
219
indicates significant free radical scavenging activity of the
compound.
2.2.
ABTS method
The ABTS radical scavenging method was developed by RiceEvans and Miller in 1994 and was then modified by Re et al. in
1999. The modification is based on the activation of metmyoglobin with hydrogen peroxide in the presence of ABTS•+ to
produce a radical cation. This improved method generates a
blue/green ABTS•+ chromophore via the reaction of ABTS and
potassium persulfate and is now widely used. Along with the
DPPH method, the ABTS radical scavenging method is one of
the most extensively used antioxidant assays for plant samples.
The ABTS radical cation is generated by the oxidation
of ABTS with potassium persulfate, and its reduction in
the presence of hydrogen-donating antioxidants is measured
spectrophotometrically at 734 nm. This decolourisation assay
measures the total antioxidant capacity in both lipophilic and
hydrophilic substances. The effect of the antioxidant concentration and the duration of the inhibition of the radical cation’s
absorption are taken into account when the antioxidant activity is determined. Trolox, a water-soluble analog of Vitamin E,
is used as a positive control. The activity is expressed in terms
of the Trolox-equivalent antioxidant capacity of the extract
(TEAC/mg).
2.3.
ORAC assay
The ORAC assay uses beta-phycoerythrin (PE) as an oxidizable protein substrate and 2,2′ -azobis(2-amidinopropane)
dihydrochloride (AAPH) as a peroxyl radical generator or a
Cu2+ -H2 O2 system as a hydroxyl radical generator. To date, it
is the only method that takes the free radical reaction to completion and uses an area-under-the-curve (AUC) technique for
quantification, thereby combining both the inhibition percentage and the length of the inhibition time of the free radical’s
action into a single quantity. The assay has been widely used
in many recent studies of plants.
2.4.
PCL assay
The PCL assay measures the antioxidant capacity of a compound against the superoxide radical in lipid (ACL) and
aqueous (ACW) phases. This method allows the quantification
of the antioxidant capacity of both hydrophilic and lipophilic
substances either as pure compounds or as a component in a
complex matrix from various origins, including synthetic, vegetable, animal, or human sources. The PCL method is based on
an approximately 1000-fold acceleration of the oxidative reactions in vitro when compared to normal conditions because
of the presence of an appropriate photosensitiser. The PCL
method is a very quick and sensitive method of measurement. Using the PCL assay, researchers have determined the
antioxidant properties of marigold flowers.
2.5.
ˇ-Carotene linoleic acid bleaching assay
The -carotene linoleic acid bleaching assay was first
described by Miller (1971) and is one of the antioxidant assays
suitable for plant samples. In this assay, the antioxidant
capacity is determined by measuring the inhibition of the production of volatile organic compounds and the formation of
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food and bioproducts processing 8 9 ( 2 0 1 1 ) 217–233
conjugated diene hydroperoxides arising from linoleic acid
oxidation, which results in the discolouration of -carotene.
-Carotene (0.5 mg) in 1 ml of chloroform is added to 25 l
of linoleic acid and 200 mg of the Tween 40 emulsifier mixture. After evaporation of the chloroform under vacuum,
100 ml of oxygen-saturated distilled water is added with vigorous shaking. Next, 4 ml of this mixture is transferred into
test tubes containing different concentrations of the sample. As soon as the emulsion is added to each tube, the zero
time point absorbance is measured at 470 nm using a spectrophotometer. The emulsion is incubated for 2 h at 50 ◦ C.
A blank, devoid of -carotene, is prepared for background
subtraction. Quercetin, BHT and ␣-tocopherol are used as
standards.
2.6.
Reducing power assay
The reducing power of the samples is determined according
to the method described by Oyaizu (1986). The sample in 1 ml
of methanol is mixed with a phosphate buffer (5 ml, 0.2 M, pH
6.6) and potassium ferricyanide (5 ml, 1%), and the mixture
is incubated at 50 ◦ C for 20 min. Next, 5 ml of trichloroacetic
acid (10%) are added to the reaction mixture, which is then
centrifuged at 3000 RPM for 10 min. The upper layer of the
solution (5 ml) is mixed with distilled water (5 ml) and ferric
chloride (1 ml, 1%), and the absorbance is measured at 700 nm.
A stronger absorbance indicates increased reducing power.
2.7.
NBT assay or the superoxide anion scavenging
activity assay
The superoxide anion scavenging activity assay was first
described by Beauchamp and Fridovich (1971). The scavenging
potential for superoxide radicals is analysed with a hypoxanthine/xanthine oxidase-generating system coupled with a
nitroblue tetrazolium (NBT) reduction (measured spectrophotometrically). The reaction mixture contains 125 l of buffer
(50 mM KH2 PO4 /KOH, pH 7.4), 20 l of a 15 mM Na2 EDTA solution in buffer, 30 l of a 3 mM hypoxanthine solution in buffer,
50 l of a 0.6 mM NBT solution in buffer, 50 l of xanthine oxidase in buffer (1 unit per 10 ml buffer) and 25 l of the plant
extract in buffer (a diluted, sonicated solution of 10 g per
250 l buffer). Microplates (96 wells) are read at 540 nm 2.5 min
after the addition of the xanthine oxidase using the series
7500 Microplate Reader. The superoxide scavenging activity
is expressed as percent inhibition compared to the blank, in
which buffer is used in place of the extract. When using this
system, any inhibition by tannins in the plant extracts would
have to be due to their antioxidant activity and not to their
action upon the enzyme.
2.8.
Total flavonoid content
Total flavonoid content has been discussed by several authors
(Dai et al., 1995; Moreno et al., 2000; Sakanaka et al., 2005).
The measurement of an extract’s flavonoid concentration is
based on the method described by Moreno et al. (2000) with a
slight modification, and the results are expressed as quercetin
equivalents. An aliquot of 1 ml of a methanol solution containing 1 mg of extract is added to test tubes containing 0.1 ml of
10% aluminium nitrate, 0.1 ml of a 1 M potassium acetate solution and 3.8 ml of methanol. After 40 min at room temperature,
the absorbance is measured at 415 nm. Quercetin is used as a
standard.
2.9.
Folin-Ciocalteu method
The Folin-Ciocalteu reagent assay is used to determine the
total phenolics content (Singlenton and Rossi, 1965). The sample (0.2 ml) is mixed with 0.5 ml of the Folin-Ciocalteu reagent
previously diluted with 7 ml of deionised water. The solution is allowed to stand for 3 min at 25 ◦ C before 0.2 ml of
a saturated sodium carbonate solution is added. The mixed
solution is allowed to stand for another 120 min before the
absorbance at 725 nm is measured. Gallic acid is used as a standard for the calibration curve. The total phenolics content is
expressed as mM gallic acid equivalents (GAE) per l of sample
(mM/l).
3.
Medicinal species with high antioxidant
potential
Several authors have also reviewed medicinal species with
great antioxidant potential (Speroni and Scartezzini, 2000;
Matkowski, 2008; Ali et al., 2008). In this work, we have
reviewed the antioxident potential of a number of additional
plants.
3.1.
Diospyros abyssinica
Diospyros species have been used in many traditional medical systems around the world, including traditional Ayurvedic,
African and Chinese medicine. Nearly every part of these
plants has been used as a medicine in some way, for example
as an astringent remedy and to cure biliousness (Mallavadhani
et al., 1998). In India, a juice made from the bark and leaves
of Diospyros peregrine combined with the root juice of Albizia
lebbeck is used as a remedy for snakebites. In Japan, the leaves
of Diospyros kaki are used in combination with jasmine to make
anti-smoking candies (Mallavadhani et al., 1998).
The most frequently-isolated compounds from Diospyros
abyssinica are the triterpenoids betulin, betulinic acid and
lupeol (Zhong et al., 1984; Recio et al., 1995). All of these compounds are well-known anti-inflammatory compounds. This
species has a significant medicinal value demonstrated by its
use in traditional medicine.
The root bark from D. abyssinica has been tested regarding its antioxidant activity (Maiga et al., 2006). It was
extracted with a series of solvents, including petroleum
ether, dichloromethane, chloroform, 80% aqueous ethanol,
and water (at 50 ◦ C and 100 ◦ C). It was determined that the root
bark from D. abyssinica is the richest source of extracted compounds; 36.7% of the weight of the plant material is composed
of antioxidants. D. abyssinica exhibited the greatest radical
scavenging activity and the greatest 15-lipoxygenase inhibition in the 80% ethanol and methanol extracts. Thus, this plant
appears to be an excellent source of antioxidants (Maiga et al.,
2006).
3.2.
Pistacia lentiscus
Pistacia lentiscus is extensively used in folk medicine by rural
populations in Algeria. Algeria is home to at least 3164 species
of vascular plant, of which 7.9% are endemic. P. lentiscus is
important because of its medicinal value. The reducing power
and radical scavenging activity of the extracts from the leaves
of P. lentiscus in solvents, such as ethanol, ethyl acetate, aqueous/ethyl acetate, hexane, aqueous/hexane, chloroform, and
food and bioproducts processing 8 9 ( 2 0 1 1 ) 217–233
aqueous chloroform has been studied in vitro (Atmani et al.,
2009).
Using the DPPH scavenging activity assay, it was found that
all of the P. lentiscus extracts, except for the chloroform extract,
have a high radical scavenging activity (90%) equivalent to
that of the standard, BHA (89%). The ethanolic and aqueous
fractions from the ethyl acetate extract have high scavenging activities with values of 78 ± 0.93% and 90.29 ± 0.29%,
respectively. Overall, P. lentiscus exhibited outstanding reducing power, good radical scavenging activity against DPPH and
H2 O2 , slow inhibition of lipid peroxidation and richness in tannins; however, it also showed a lack of flavonoids (Atmani et
al., 2009).
A strong correlation was found between reducing power
and the total amount of phenols present in P. lentiscus, indicating that the phenol compounds play an important role in
the beneficial effects of these medicinal plants. This finding is
in agreement with the work of Chryssavgi et al. (2008), which
demonstrated that the greatest phenolic content in P. lentiscus
is 588 mg gallic acid/g of plant material and consists mainly of
monoterpenes (81.6%).
3.3.
Geranium sanguineum L
Geranium sanguineum L., commonly found in Bulgaria, has significant antioxidant activity and antiviral activity (Serkedjieva
and Manolova, 1992). Its root extracts are used in traditional
medicine to treat gastrointestinal disorders, infections and
inflammatory conditions. It is also frequently used in folk
medicine for the treatment of eruptive skin diseases and as
a disinfectant bath and poultice for the affected area.
The polyphenolic compounds of this plant species include
tannins (11.02%), flavonoids (0.14%), catechins and proanthocyanidines (2.1 mg/kg) (Ivancheva et al., 1992). Using three
separate, complementary methods (the DPPH assay, the carotene-linoleic acid assay and the NBT-reduction assay),
it was established that a polyphenol-rich extract from G.
sanguineum L., which had a strong anti-influenza activity, possessed antioxidant and radical scavenging capacities. In this
study, caffeic acid and the synthetic antioxidant BHT were
used as positive controls.
The root extract of this plant exhibited a strong antioxidant
capacity in the DPPH assay (IC50 = 13.86 ± 0.84 g/ml) when
compared to BHT (IC50 = 19.81 ± 0.05 g/ml). In the -carotenelinoleic acid test system, the root extract achieved 88–89%
inhibition, which is as strong as BHT’s inhibition. Furthermore, the total extract and ethyl acetate fraction exhibited
a strong superoxide dismutase (SOD) activity, comparable to
that of caffeic acid. In addition, the total methanol-soluble
phenolic constituents were measured with the Folin-Ciocalteu
reagent and were found to be 34.6% (w/w) (Sokmen et al., 2005).
In another study, it was found that G. sanguineum L. reduced
the accumulation of TBA-reactive products in rat liver microsomes in vivo in the induced LPO method, but the non-induced
LPO method was not affected (Murzakhmetova et al., 2008).
China is the only country on Earth in which there are unbroken connections among tropical, subtropical, temperate and
boreal forests. This unbroken connection has fostered the formation of rich plant associations rarely seen elsewhere in the
world. China’s plant life is enormously rich. Some 31,000 plant
species are native to China, representing nearly one-eighth
of the world’s total plant species, including thousands found
nowhere else on Earth. Chinese medicinal plants contain a
wide variety of natural antioxidants, such as phenolic acids,
flavonoids and tannins and possess more potent antioxidant
activity than common dietary plants (Cai et al., 2004; Dragland
et al., 2003). Sargentol, tyrosol, salidroside, methylprotocatechuate, vanillic acid, syringic acid, p-hydroxy benzoic acid, and
ferulic acid have been identified in this plant (Li et al., 2008).
Using the FRAP and TEAC assays, S. cuneata Rehd. Et Wils
was found to have the greatest antioxidant capacity with
453.53 mol Fe(II)/g and 265.43 mol Fe(II)/g, respectively. In
addition, S. cuneata Rehd. Et Wils had the highest phenolic
content (52.35 mg GAE/g). A strong correlation was also found
between the TEAC and FRAP values, which implies that the
extracts from this plant are capable of scavenging free radicals and reducing antioxidants (Li et al., 2008). This study
concludes that this medicinally-important species is a valuable source of natural antioxidants, both for the preparation
of crude extracts and for the further isolation and purification
of antioxidant components.
3.5.
Polyalthia cerasoides (Roxb.) Bedd
Polyalthia cerasoides (Roxb.) Bedd. (Annonaceae) is a mediumsized tree distributed in almost all of the forests of Deccan
India at elevations of up to 3000 ft. India is one of the richest
countries in the world with respect to medicinal and aromatic
plants. The plant life of India constitutes 11% of the world’s
total known flora that have medicinal properties. The number
of plant species in India is estimated to be over 45,000.
The tribal people of Tamil Nadu and Andhra Pradesh (states
of India) use the fruits of this plant, while tribes in Africa
use the fruits, roots and leaves to treat rheumatism and
toothaches, as an aphrodisiac, as a deparasitant and as an
anti-inflammatory. Pharmacological studies confirmed that
the stem bark of P. cerasoides reduces brain stress.
The antioxidative potential of the alcohol extract of P.
cerasoides was evaluated using the DPPH, hydroxyl radical,
superoxide anion scavenging, and reducing power assays. The
methanol extract of P. cerasoides exhibited a significant dosedependent inhibition of DPPH scavenging activity with 50%
inhibition occurring at a concentration equivalent to 25 g/ml
of tannic acid. The total phenolic content of the alcohol extract
of P. cerasoides was equivalent to 0.589 g of tannic acid per mg
of extract (Ravikumar et al., 2008). The phenolic compounds
present in the extract may contribute directly to the antioxidative action of the plant, suggesting that the polyphenols
present in the extract could be responsible for its beneficial
effects.
3.6.
3.4.
221
Crataeva nurvala Buch-Ham
Sargentodoxa cuneata Rehd. Et Wils
In the classification of Chinese medicinal plants, Sargentodoxa
cuneata Rehd. Et Wils falls into the “heat-clearing” category.
The plants in this category have significant anti-inflammatory,
anti-tumour, anti-allergic, anti-viral and anti-bacterial activities.
Crataeva nurvala Buch-Ham. is used extensively in traditional
medicine as a blood purifier. The bark of C. nurvala is used
in herbal powders to treat urinary stones, thyroid disorders,
obesity and cancer.
C. nurvala has a higher total antioxidant capacity
than catechin (Kumari and Kakkar, 2008). In this study,
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food and bioproducts processing 8 9 ( 2 0 1 1 ) 217–233
C. nurvala showed the highest SOD mimetic activity
(122.53 unit/min/mg), which was determined spectrophotometrically by measuring inhibition in the nicotinamide
adenine dinucleotide (reduced)-phenazine methosufatenitroblue tetrazolium reaction system. C. nurvala was found
to have the highest LPO inhibitory potential. C. nurvala was
more efficient at scavenging peroxide radicals than catechin.
Using the ABTS assay, the total antioxidant potential of C.
nurvala was found to be 0.39 mmol/l TEAC/mg of extract. In
addition, a study of this plant’s phytochemicals revealed that
the stem bark of C. nurvala contained triterpenoids such as
phragmalin triacetate and lupeol.
3.7.
Acacia auriculiformis A. Cunn
Acacia auriculiformis A. Cunn is a vigorously-growing deciduous or evergreen tree. It can reach heights of up to 30 m and
belongs to the family Mimosaceae. It is rich in methylglucuronic
acid, glucuronic acid, galactose, arabinose, and rhamnose.
Tannins and triterpenoid saponins are present in the
species (Parkashi et al., 1991; Ghosh et al., 1993; Garai and
Mahato, 1997). In addition, extracts from the Acacia species
are rich in phenols and polyphenols and have strong antimutagenic and antioxidant activities (Kaur et al., 2002, 2005; Singh
et al., 2004).
The hydroxyl radical scavenging potency of the extracts of
A. auriculiformis increased with solvent polarity and was greatest in the water fraction, followed by the ethyl acetate fraction,
and the crude extract. The water fraction had a higher phenolic content (720 mg) than the ethyl acetate fraction (600 mg)
or the crude ethyl acetate extract (390 mg) when expressed as
GAE/g of extract/fraction (Singh et al., 2007).
3.8.
Teucrium polium L
Teucrium polium L. is a wild flower species belonging to
the Lamiaceae family, which is composed of numerous
species with exploitable antioxidant activity (Del Bano et al.,
2003). An infusion of the leaves and flowers of the plant is
consumed as a refreshing beverage. This infusion is also used
for liver ailments, gastrointestinal diseases, fevers, colds, diarrhoea, stomach pains and fevers.
In this study, the aerial part of the plant was extracted with
petroleum ether, chloroform, methanol and water. The antioxidant flavonoids were separated from the methanol extract
and were identified as rutin, apigenin, 3′ ,6-dimethoxy apigenin and 4′ ,7-dimethoxy apigenin; their IC50 values in the
DPPH assay were found to be 23.7 ± 1.9 g/ml, 30.3 ± 2.1 g/ml,
31.5 ± 3.4 g/ml and 37.4 ± 3.4 g/ml, respectively. The DPPH
assay IC50 value for the methanol extract was found
to be 20.1 ± 1.7 g/ml; this value is similar to the IC50
value of the synthetic antioxidant, butylated hydroxytoluene
(18.3 ± 1.9 g/ml). The potential antioxidant activity and the
rich flavonoid content of T. polium suggests that its extracts
may be added to various food products in place of synthetic
antioxidants (Sharififar et al., 2009).
The aqueous extract of T. polium can effectively inhibit
oxidative processes and has substantial antioxidant activity
in vitro (Ljubuncic et al., 2006). The ethanol extract prepared
from T. Polium exhibited the same antioxidant activity as ␣tocopherol. The antioxidant activity of T. polium was also
demonstrated in a recent in vivo study of rats. Rats were treated
with a T. polium extract that showed significant antioxidant
activity in the DPPH test compared to the positive control (␣-
tocopherol). The T. polium extract given to rats at doses of 50
and 100 mg/kg significantly increased the total antioxidant
power (TAP) and decreased the thiobarbuteric acid reactive
substances (TBARS) relative to the control (Hasani et al., 2007).
3.9.
Dracocephalum moldavica L
The Moldavian balm (Dracocephalum moldavica L., Lamiaceae)
is a perennial herb that is native to central Asia and is naturalised in eastern and central Europe. It is used as a food
ingredient, a tea, and as an herbal drug used to treat stomach and liver disorders, headaches and congestion (Rechinger,
1986).
The antioxidant activity of this species has been studied by several researchers (Povilaityte and Venskutonis, 2000;
Povilaityte et al., 2001; Dastmalchi et al., 2007). Dastmalchi
et al. (2007) suggested that the components responsible
for its activity were hydroxycinnamic acids and flavonoids,
including caffeic acid, ferulic acid, rosmarinic acid, luteolin,
luteolin-7-O-glucoside and apigenin. The extract yields ranged
from 3.7 mg/g in the ethyl acetate and n-butanol extracts
to 109.2 mg/g in the methanol extract; they increased in
the following order: ethyl acetate and n-butanol, acetonitrile (ACN), dichloromethane, petrol, water and methanol. The
total phenolic content of the extracts ranged from 0.0 ± 0.0 mg
GA/g in the petrol extract to 488.4 ± 1.8 mg GA/g in the
methanol extract and increased in the following order: petrol,
dichloromethane, ACN, ethyl acetate, water, n-butanol and
methanol.
The HPLC-determined total phenolic content of the raw
material was found to be 476.59 ± 25.22 mg/g (sum of the
individual extracts). Rosmarinic acid was the most abundant component identified (247.95 ± 24.78 mg/g), followed
by chlorogenic acid (41.46 ± 2.76 mg/g) and apigenin-7-Oglucoside (26.55 ± 2.20 mg/g). The greatest quantities of
phenolic substances were found in the n-butanol (39%),
methanol (31.1%) and water (11.5%) fractions (Dastmalchi et
al., 2007).
3.10.
Urtica dioica L
Urtica dioica L. (Urticaceae) leaves have been used in Sardinia,
Italy as a medicinal tea or decoction as diuretic and antidiabetic therapies and to treat stomach disorders. The flora
of Italy is the richest in Europe. As of 2004, 6759 species had
been recorded in the data bank of Italian vascular flora, of
which 700 are endemic. U. dioica L. leaves are also used to treat
stomachaches in Turkish folk medicine (Yesilada et al., 1993).
The antioxidant capacity of this plant was evaluated using
several in vitro methods (BR, TEAC, DPPH, and FC). The BR
method determined that the antioxidant activity of U. dioica
at an acidic pH was 0.013 ± 0.001 g/ml resorcinol equivalents
(Re eq.); the DPPH method in methanolic solutions determined
that the antioxidant activity was 419 ± 10 g/ml. The total phenolic content was found to be 0.35 ± 0.02 mg/l GAE (Dall’Acqua
et al., 2008).
Concentrations of U. dioica L. extract of 50, 100 and
250 g/ml showed 39%, 66% and 98% inhibition, respectively,
of the peroxidation of a linoleic acid emulsion. However, ␣tocopherol, positive control, at 60 g/ml, exhibited only 30%
inhibition (Gulcin et al., 2004). It can be concluded that U. dioica
L. has powerful antioxidant activities.
food and bioproducts processing 8 9 ( 2 0 1 1 ) 217–233
3.11.
Ficus microcarpa L. fil
Ficus microcarpa L. fil. (Chinese banyan tree, Moraceae) is
a popular ornamental tree grown widely in many tropical
regions. It is native to areas including Ceylon, India, southern China, the Ryukyu Islands, Australia and New Caledonia.
It is also a popular ornamental plant in Taiwan (Chiang
et al., 2005). Its dried leaves, aerial roots and bark have
been used as folk remedies to decrease perspiration, alleviate fever and relieve pain in the Okinawa Islands. There are
about 7000 species of vascular plants in Japan, and about
40% of these, approximately 2900 species, are recognized as
endemic.
In the study, two isoflavones comprised of 28 components were identified in the bark of the F. microcarpa tree
(Kuo and Li, 1997). In addition, the methanol extracts of this
tree’s bark, fruits and leaves exhibited strong antioxidant
activity when assayed by the DPPH method, the ABTS free
radical scavenging method, the PMS-NADH system superoxide radical scavenging assay and the -carotene-linoleic
acid system. The methanol extract of the bark showed
stronger antioxidant activity than the extracts of the leaves
or fruits in the ABTS method, the PMS-NADH method and
the -carotene-linoleic acid system. However, no significant
difference was found between the bark and the fruits in the
DPPH assay. Furthermore, the bark contained a significantly
higher amount of total phenolics (237 mg GAE/g extract) than
the fruits (179 mg GAE/g extract) or the leaves (127 mg GAE/g
extract).
Furthermore, the total phenolics in the bark were
present in greater amounts in the ethyl acetate fraction
than in the aqueous fraction and the hexane fraction;
the values were 436, 194 and 41.7 mg GAE/g extract,
respectively. The ethyl acetate fraction contained twelve
phenolic compounds, of which seven were quantified by
HPLC: protocatechuic acid (6.60 ± 0.20 mg/g extract), catechol
(11.1 ± 0.00 mg/g extract), p-vinylguaiacol (4.40 ± 0.07 mg/g
extract), syringol (173 ± 1.12 mg/g extract), p-propylphenol
(10.5 ± 0.78 mg/g extract), vanillin (4.27 ± 0.02 mg/g extract)
and syringaldehyde (8.96 ± 0.29 mg/g extract) (Ao et al., 2008).
3.12.
Bidens pilosa Linn. Radiata
Bidens pilosa Linn. Radiata (family Asteraceae) is widely distributed in subtropical and tropical regions. It is 30–100 cm in
height with yellow flowers and is commonly known as “hairy
beggar ticks,” “sticks tights,” and “Spanish needles.” The plant
is used in various folk medicines for its anti-inflammatory,
antiseptic, liver-protective, blood-pressure lowering, and antihypoglycaemic effects (Dimo et al., 2002). The plant has been
widely used in Taiwan as a traditional medicine and as a major
ingredient of an herbal tea that is believed to prevent inflammation and cancer (Yang et al., 2006).
Phenylpropanoid glucosides, polyacetylenes, diterpenes,
flavonoids and flavone glycosides have been identified as
the bioactive components of this plant and are thought to
be involved in its antioxidant activity (Chiang et al., 2004).
The methanol extract of B. pilosa was shown to prevent the
onset of hypertension and to reduce blood pressure in rats
(Dimo et al., 2002). In addition, the fresh leaves and flowers
of B. pilosa were subjected to steam-distillation, and colourless and yellowish essential oils were obtained in amounts of
0.08% and 0.06% (w/w), respectively. GC-MS analysis of these
essential oils resulted in the identification of forty-four com-
223
pounds including the major essential oils, -caryophyllene
(10.9% and 5.1% in the leaves and flowers, respectively)
and -cadinene (7.82% and 6.13% in the leaves and flowers, respectively). Both of these essential oils are terpenes.
The other chemical components were ␣-pinene, limonene,
-trans-ocimene, -cis-ocimene, -muurolene, -bourbonene,
-elemene, -cubebene, ␣-caryophyllene, caryophyllene oxide
and megastigmatrienone.
The essential oils in the leaves and flowers were able to
reduce the stable free radical DPPH to the yellow coloured
diphenylpicrylhydrazine with IC50 s of 57 and 50 g/ml, respectively, whereas the synthetic and natural antioxidant activities
were 21 and 36 g/ml, respectively. This study revealed that
the flowers of B. pilosa have an antioxidant activity that is similar to that of synthetic antioxidants. In addition, the aqueous
extracts of the flowers and leaves were found to be less efficient in radical scavenging and had IC50 values of 172 g/ml
and 61 g/ml, respectively. Furthermore, the essential oils of
the leaves and the aqueous extracts of the leaves and flowers
exhibited higher antioxidant activities than did the flower oils.
The lower activity of the essential oils of B. pilosa’s flowers may
be due to their volatility at higher temperatures. The study
showed that the antioxidant effects of essential oils depend
not only on the temperature but also on other factors such as
their structural features, the characteristics of the lipid system, and the binding of the fatty acids (Deba et al., 2008).
3.13.
Leea indica
Leea indica, a member of the Leeaceae family, was studied for
its antioxidant and nitric oxide inhibitory properties because
of its traditional use for various medicinal purposes. It is
commonly found in Malaysia. Malaysian tropical rainforests
contain many species that are important sources of traditional
medicines. About 10,000 species of higher plants and 2000
species of lower plants are available in Peninsular Malaysia;
16% of these are used for traditional medicinal purposes (Lattif
et al., 1984).
The leaves of Leea indica contain 23 relevant chemical
compounds, including eleven hydrocarbons, phthalic acid,
palmitic acid, 1-eicosanol, solanesol, farnesol, three phthalic
acid esters, gallic acid, lupeol, beta-sitosterol and ursolic acid
(Srinivasan et al., 2008).
This study used the FTC and TBA methods to demonstrate
that methanol extracts of Leea indica had strong antioxidant activity that is comparable to, or higher than, that
of ␣-tocopherol, BHT and quercetin. Saha et al. (2004) also
confirmed that extracts from Leea indica had strong activity
compared with the standards (i.e., vitamin C, quercetin and
BHT). The high antioxidant activity of Leea indica extracts may
be due to the presence of gallic acid.
3.14.
Lamiaceae species
Six Lamiaceae species (i.e., Leonurus cardiaca, Lamium album,
Marrubium vulgare, Stachys officinalis, Lamium purpureum
and Galeopsis speciosa) are rich in antioxidant activity. Leonurus cardiac L. is a mild cardiac drug containing flavonoid and
phenolic glycosides.
The chemical composition, therapeutic uses and pharmacological properties of these species have been reported.
Lamium album L. (dead nettle) has antispasmodic, diuretic and
haemostatic properties and is used to alleviate bladder, kidney and menstrual problems. Lamium purpureum L. is used
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food and bioproducts processing 8 9 ( 2 0 1 1 ) 217–233
for similar medicinal purposes. Marrubium vulgare L., which
contains diterpenoids, iridoids, flavonoids and terpenoid, is
used to treat coughs and digestive disorders. Stachys officinalis
Franch. is used for antiseptic, astringent, tonic, anthelmintic
and digestive purposes. Galeopsis speciosa, which contains tannins, flavonoids, soluble silica and saponins, is used as an
astringent, diuretic and expectorant.
The antioxidant activities of these six species have been
studied by several authors (Mantle et al., 2000; Trouillas et al.,
2003; Vander Jagt et al., 2002), but it is difficult to compare their
results because of the methodological differences between
the studies (Matkowski and Piotrowska, 2006). In addition, the
antioxidative effects of the methanolic extracts from six wild
European Lamiaceae species have been studied using three in
vitro assays.
In the DPPH scavenging assay, the order of these species
from strongest to weakest antioxidant activity was: Leonurus
cardiaca, Lamium album, Marrubium vulgare, Stachys officinalis,
Lamium purpureum and Galeopsis speciosa. In the LPO assay,
S. officinalis and M. vulgare reached a maximum inhibition of
78%, Lamium sp. and L. cardiac slightly exceeded 70% while G.
speciosa reached 65%. All of the extracts contained a considerable quantity of phenolic metabolites, ranging from 13.2% GAE
in S. betonica to 20% in L. cardiaca (Matkowski and Piotrowska,
2006). L. cardiaca has significant antioxidant potential, as
demonstrated by several authors (Mantle et al., 2000; Trouillas
et al., 2003; Vander Jagt et al., 2002).
3.15.
Uncaria tomentosa (Willd.) DC
Uncaria tomentosa (Willd.) DC., commonly known as cat’s claw,
belongs to the family Rubiaceae and is found in South and Central America. It is used for the treatment of asthma, cancer,
cirrhosis, fevers, gastritis, diabetes, dysentery and inflammation of the urinary tract (Keplinger et al., 1999; Falkiewicz and
Lukasiak, 2001; Heitzman et al., 2005). In addition, it is used
as an anticancer remedy and has anti-inflammatory properties (Aguilar et al., 2002). Due to the chemical structure of its
components, this plant is expected to have strong antioxidant
activity (Deschmarchelier et al., 1997).
The active chemical constituents of this species are alkaloids, quinoic acid, glycosides, polyhydroxylated triterpenes
and several steroidal components. The antioxidant properties of the aqueous and ethanolic extracts of U. tomentosa
bark have been evaluated. A higher antioxidant activity
and greater number of total phenolic compounds were
detected in the alcoholic preparations (TEAC = 0.57 mmol of
Trolox/g and SOD = 0.39 U/mg) than in the aqueous preparations (TEAC = 0.34 mmol of Trolox/g and SOD = 0.1 U/mg). This
study revealed that five pentacyclic oxindole alkaloids, including uncarine F, speciophylline, mitraphylline, isomitraphylline
and/or pteropodine and isopteropodine, were present in the
bark.
The content of TPC in the ethanol extract from U. tomentosa bark (292 mg/g D-catechin units) was two times higher
than in the aqueous extract (111 mg/g). These values are very
high compared to other TPC-containing cereals (from 0.481
to 0.896 mg/g), vegetables (e.g., 11.7 mg/g for broccoli, 9.9 mg/g
for garlic and 7.6 mg/g for pepper) and fruits (e.g., 23.1 mg/g
for blackberries) (Vinson et al., 1998; Wang and Lin, 2000). The
ethanol extract showed higher superoxide radical scavenging
activity (0.39 U/mg) than did the aqueous extract (0.10 U/mg)
(Pilarski et al., 2006).
3.16.
Salvia officinalis L
Common sage (Salvia officinalis L., Lamiaceae) is an aromatic
and medicinal plant of Mediterranean origin commonly found
in Portugal and Lithuania and well known for its antioxidant
properties that are mainly due to its phenolic-rich composition.
Methanolic and aqueous extracts were prepared from
the aerial parts of S. offcinalis and analysed for phenolic compounds by HPLC/DAD. Eight phenolic compounds
were identified, including five phenolic acids (i.e., rosmarinic acid, caffeic acid, ferulic acid, 3-caffeoylquinic
acid and 5-caffeoylquinic acid) and three flavonoids (i.e.,
luteolin-7-glucoside; 4′ ,5,7,8-tetrahydroxyflavone; apigenin-7glucoside). The methanolic extract had a higher content of
these compounds than did the aqueous extract.
The main phenolic compound in the methanolic extract
was rosamarinic acid (132.2 g/mg extract), while the main
compounds in the aqueous extract were rosamarinic acid
(52.0 g/mg extract) and luteolin-7-glucoside (19.7 g/mg
extract). The methanolic extract had a higher content of
phenolic compounds and a higher anti-radical activity in
the DPPH assay (IC50 = 13.5 ± 0.5 g/ml) and a higher antiradical efficiency than the aqueous extract, which had an IC50
of 14.9 ± 0.3 g/ml. The activity of both extracts was lower
than the positive control, quercetin. In the superoxide radical
scavenging assay, the aqueous extract had a greater antiradical activity (14.4 ± 1.4 g/ml) than the methanolic extract
(162 ± 39 g/ml) (Lima et al., 2007). A separate study showed
that replacing the drinking water of rats and mice with S. officinalis infusions for 14 days led to improved liver antioxidant
status (Lima et al., 2005).
3.17.
Momordica Charantia L
The bitter gourd (Momordica Charantia L.) or Mara (in Thai)
belongs to the family Cucurbitaceae and has long been used in
foods and medicines (El Batran et al., 2006). The bitter gourd is
known by different names, such as balsam pear and karela,
and it grows in tropical and sub-tropical regions of India,
Malaysia, China, Africa, the Middle East, USA and Thailand (El
Batran et al., 2006). Thailand is home to a wide range of herbal
plant species. Medicinal plants and herbs have long been a
part of everyday life in Thailand; many are used as spices in
various Thai dishes. The therapeutic efficacy of Thai medicinal
plants and traditional herbal medications has been scientifically proven and described in the literature by both Thai and
non-Thai scientists. The bitter gourd can be used to treat diabetes mellitus and appears to be a safe alternative to reduce
blood glucose (Virdi et al., 2003).
In the DPPH radical scavenging assay, the activity of the
positive control, ascorbic acid, was the highest (200 mg/ml),
followed by BHT, the leaf, the green fruit, the stem and
the ripe fruit fractions of the bitter gourd. The IC50 values were lowest in the leaf fraction (9.72 ± 0.25 mg/ml),
followed by the green fruit fraction (11.00 ± 0.76 mg/ml), the
stem fraction (17.8 ± 0.66 mg/ml) and the ripe fruit fraction (27.6 ± 0.23 mg/ml). In the hydroxyl radical scavenging
assay, the activity of the leaf fraction was greater than
that of the other fractions but lower than that of ascorbic
acid and BHT. The green fruit had the highest IC50 value
(119 ± 0.34 mg/ml), followed by the leaf (167 ± 0.96 mg/ml), the
stem (267 ± 0.72 mg/ml) and the ripe fruit (173 ± 0.23 mg/ml).
In the -carotene-linoleate bleaching assay, the antioxi-
Table 1 – Worldwide distribution of medicinal plants with superior antioxidant potential.
Africa
Algeria
USA
Australia
Brazil
Bulgaria
China
India
Iran
Italy
Japan
Malaysia
Poland
Portugal
Thailand
Turkey
Plant species
Diospyros
Pistacia
Geranium
Sargentodoxa Polyalthia
Crataeva
Acacia
Teucrium
Urtica
Dracocephalum
abyssinica
lentiscus
sanguineum
cuneata
cerasoides
nurvala
auriculi-
polium L.
moldavica
L
Rehd. Et
(Roxb.)
Buch-
formis A.
Wils
Bedd.
Ham.
Cunn
+
dioica L.
L.
Ficus
Bidens
Leea
Lamiaceae
Uncaria
Salvia
Momordica
Rheum
Pelar-
micro-
pilosa
indica
species
tomentosa
officinalis
Charantia L.
ribes L.
gonium
carpa
Linn.
(Willd.)
L.
L. fil.
Radiata
DC.
rianum
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
endliche-
food and bioproducts processing 8 9 ( 2 0 1 1 ) 217–233
Land mass
+
+
+
+
+
+
225
226
Table 2 – Extraction methods, main components and antioxidant potential of medicinal plant species.
S. No.
Extraction
method
Solvent(s) used
Main components (or
groups)
Antioxidant assay methods
1
Diospyros
abyssinica (root
bark)
Soxhlet
extraction
Triterpenoids, betulin,
betulinic acid and lupeol
DPPH assay: (80%
ethanol)
EC50 = 16 ± 2 g/ml
15-lipoxygenase
inhibition (80% ethanol):
IC50 = 21 ± 2 g/ml
NA
NA
Maiga et al.,
2006; Zhong et
al., 1984; Recio et
al., 1995
2
Pistacia lentiscus
(leaves)
Solvent
extraction
Monoterpenes
Reducing power assay
(aqueous hexane):
0.91 ± 0.03
DPPH assay (aqueous
chloroform):
IC50 = 4.24 g/ml
Inhibition of
linoleic acid
peroxidation
(aqueous
hexane): 98.77%
NA
Atmani et al.,
2009; Chiang et
al., 1993;
Chryssavgi et al.,
2008
3
Geranium
sanguineum L
(root)
Sargentodoxa
cuneata Rehd. Et
Wils (plant)
Solvent
extraction
Petrol, ether,
dichloro
methane,
chloroform, 80%
ethanol,
methanol, and
water (50 ◦ C and
100 ◦ C)
Ethanol, ethyl
acetate, aqueous
ethyl acetate,
hexane, aqueous
hexane,
chloroform and
aqueous
chloroform
Methanol
DPPH assay:
IC50 = 13.86 ± 0.84 g/ml
-carotene- linoleic acid
assay: 88–89% inhibition
Methanol
FRAP assay: 453.53 mol
Fe (II)/g
TEAC assay: 265.43 mol
Fe (II)/g
NBT-reduction
assay:
IC50 = 26 g/ml
NA
NA
Hot water
extraction
Sokmen et al.,
2005; Ivancheva
et al., 1992
Li et al., 2008
5
Polyalthia
cerasoides (Roxb.)
Bedd. (stem bark)
NA
Ethanol
Tannins, flavonoids,
catechins and
proanthocyanidines
Sargentol, tyrosol,
salidroside,
methylprotocatechuate,
vanillic acid, syringic
acid, p-hydroxy benzoic
acid, and ferulic acid
NA
DPPH assay:
IC50 = 25 g/ml
Hydroxyl radical
scavenging assay:
IC50 = 50 g/ml
NA
Ravikumar et al.,
2008
6
Crataeva nurvala
Buch-Ham. (stem
bark)
Cold reflux
Ethanol
SOD mimetic activity:
122.53 unit/min/mg
LPO inhibitory potential:
83.3% LPO
inhibition/10 g of
extract
NA
Kumari and
Kakkar, 2008
7
Acacia
auriculiformis A.
Cunn (bark)
Ethyl acetate
fraction and
water fraction
DPPH assay – water
fraction decreasing
order of polarity: 67.14%
Reducing power assay –
water fraction
decreasing order of
polarity: 1.717 Fe3+ to
Fe2+
Singh et al., 2007;
Parkashi et al.,
1991; Ghosh et
al., 1993; Garai
and Mahato, 1997
Teucrium polium L.
(aerial parts)
Rutin; apigenin;
3’,6-dimethoxy
apigenin;
4’,7-dimethoxy apigenin
DPPH assay:
IC50 = 20.1 ± 1.7 g/ml
-Carotene bleaching
test: 25.8 ± 1.2 mm
inhibition
Deoxyribose
degradation
assay – water
fraction
increasing order
of polarity:
75.63%
NA
TBA assay –
Water fraction
decreasing order
of polarity:
71.62%
8
Extraction by
maceration of
bark powder by
increasing and
decreasing the
order of solvent
polarity
NA
Triterpenoids, such as
phragmalin triacetate
and lupeol; tannin,
saponin, friedelin, and
diosgenin
Tannins and
triterpenoid saponins
Superoxide
anion scavenging
activity:
IC50 = 80 g/ml
ABTS assay: 0.39
mmol/l TEAC/mg
of extract
NA
Sharififar et al.,
2009
4
Methanol
Reference(s)
NA
food and bioproducts processing 8 9 ( 2 0 1 1 ) 217–233
Species
9
Dracocephalum
moldavica L.
(aerial parts)
Soxhlet
10
Urtica dioica L.
(leaves)
11
ABTS assay
(ethyl acetate):
0.81 ± 0.03 mm
Trolox
-Carotene
linoleic acid
bleaching (ethyl
acetate):
19.2 ± 3.1%
Iron (III) reducing
assay (water
extract):
444.5 ± 6.8 mol/g
Dastmalchi et al.,
2007; Povilaityte
and Venskutonis,
2000; Povilaityte
et al., 2001
NA
BR method:
0.013 ± 0.001 g/ml Re.
DPPH assay:
419 ± 10 g/ml
Extraction
Methanol
DPPH assay (bark):
EC50 = 7.9 ± 0.1 g/ml
PMS- NADH
system
superoxide
radical
scavenging assay
(bark):
EC50 = 97.5 ± 2.8 g/ml
Ao et al., 2008;
Kuo and Li, 1997
12
Bidens pilosa Linn.
Radiata (leaves
and flowers)
Steam
distillation
Diethyl ether
DPPH assay (leaves and
flowers): IC50 = 61 and
172 g/ml, respectively
NA
NA
NA
Deba et al., 2008
13
Leea indica (plant)
Solvent
extraction
Methanol
DPPH assay:
IC50 = 25 g/ml
NA
NA
NA
Saha et al., 2004;
Srinivasan et al.,
2008
14
Lamiaceae species
(Leonurus
cardiaca, Lamium
album, Marrubium
vulgare, Stachys
officinalis, Lamium
purpureum and
Galeopsis speciosa)
(plant material)
Reflux-extracted
Methanol
Triterpenoids (lupenyl
acetate, friedelin,
glutinol, epifriedelinol,
-amyrin acetate and
-amyrin); phenolic
compounds
(protocatechuic acid,
catechol, syringol and
vanillin)
Terpenes
(-caryophyllene and
-cadinene), ␣-pinene,
limonene,
-trans-ocimene,
-cis-ocimene,
–muurolene,
-bourbonene,
-elemene, -cubebene,
␣-caryophyllene,
caryophyllene oxide and
megastigmatrienone
Phthalic acid, palmitic
acid, 1-eicosanol,
solanesol, farnesol,
three phthalic acid
esters, gallic acid,
lupeol, beta-sitosterol
and ursolic acid
Leonurus cardiac
contains flavonoid and
phenolic glycosides
Total phenolics:
0.35 ± 0.02 mg/l
GA
NA
Dall’ Acqua et al.,
2008
Ficus microcarpa L.
fil. (bark, fruit
and leaves)
TEAC assay:
0.46 ± 0.07 mm
Trolox
ABTS assay
(bark):
EC50 = 4 ± 0.0 g/ml
DPPH assay: EC50 = 0.7 (L.
cardiaca), 1 (L. album),
1.15 (M. vulgare) g/ml
Linoleic acid
peroxidation
assay 78.7 ± 5.6%
(M. vulgare)
77.8 ± 5.6% (S.
officinalis)
73.3 ± 8.6% (L.
cardiaca)
NA
NA
Matkowski and
Piotrowska, 2006;
Mantle et al.,
2000; Trouillas et
al., 2003; Vander
Jagt et al., 2002
227
DPPH assay (methanol
extract): 89.5 ± 0.2%
food and bioproducts processing 8 9 ( 2 0 1 1 ) 217–233
Caffeic acid, ferulic acid,
rosmarinic acid,
luteolin,
luteolin-7-O-glucoside
and apigenin
Ultrasound bath
Petrol,
dichloromethane,
acetonitrile,
ethyl acetate,
methanol,
n-butanol and
water
Methanol
228
Table 2 (Continued )
Species
Extraction
method
Solvent(s) used
Main components (or
groups)
Antioxidant assay methods
Reference(s)
15
Uncaria tomentosa
(Willd.) DC. (bark)
Hot water
extraction
Ethanol extract
and aqueous
extract
TEAC assay (ethanol
and aqueous): 0.57 and
0.34 mmol Trolox/g,
respectively
SOD activity
(ethanol and
aqueous): 0.39
and 0.1 U/mg,
respectively
NA
NA
Pilarski et al.,
2006
16
Salvia officinalis L.
(aerial parts)
Ultrasonic bath
Methanol extract
and water
extract
DPPH assay (methanol
and water):
IC50 = 13.5 ± 0.5
(methanol) and
14.9 ± 0.3 (water) g/ml
Superoxide
radical method
(methanol and
water):
IC50 = 162 ± 39
(methanol) and
14.4 ± 1.4 (water)
g/ml
NA
NA
Lima et al., 2007
17
Momordica
Charantia L. (leaf,
stem, green fruit
and ripe fruit)
Extraction
Distilled water
Alkaloids (uncarine,
speciophylline,
mitraphylline,
isomitraphylline,
isoteropodine); quinoic
acid, glycosides and
polyhydroxylated
triterpenes
Phenolic acids
(rosmarinic acid, caffeic
acid, ferulic acid,
3-caffeoylquinic acid
and 5-caffeoylquinic
acid); flavonoids
(luteolin-7-glucoside,
4’,5,7,8tetrahydroxyflavone,
apigenin-7-glucoside)
Gallic acid, tannic acid,
catechin, caffeic acid,
p-coumaric acid, ferulic
acid and benzoic acid
DPPH assay (leaf, stem,
green fruit and ripe
fruit): IC50 = 9.72 ± 0.25
(leaf), 17.8 ± 0.66 (stem),
11 ± 0.76 (green fruit)
and 27.6 ± 0.23 (ripe
fruit) mg/ml
Rheum ribes L.
(roots and stems)
Extraction
Chloroform and
methanol
Chrysophanol,
physcion, emodin,
quercetin,
5-desoxyquercetin, and
quercetin-3-Orhamnoside
-Carotene bleaching
method (chloroform
extracts of root at 50
and 100 g): 91.09 ± 0.8%
and 93.14 ± 1.17%,
respectively
-Carotene
linoleate
bleaching assay
(leaf, stem, green
fruit and ripe
fruit): 63.9 ± 0.71
(leaf), 36.2 ± 0.59
(stem), 79.9 ± 0.7
(green fruit) and
59 ± 0.44 (ripe
fruit) mg/ml
NA
FRAP assay (leaf,
stem, green fruit
and ripe fruit)
433 ± 0.007 (leaf),
39 ± 0.008 (stem),
43.8 ± 0.008
(green fruit) and
9.41 ± 0.007 (ripe
fruit) mol
FeSO4 /g dry
sample
NA
Kubola and
Siriamornpun,
2008
18
19
Pelargonium
endlicherianum
(aerial parts)
Soxhlet
Methanol
NA
DPPH assay:
IC50 = 7.43 ± 0.47 g/ml
Hydroxyl radical
scavenging
activity (leaf,
stem, green fruit
and ripe fruit):
IC50 = 167. ± 0.96
(leaf), 267 ± 0.72
(stem), 119 ± 0.34
(green fruit) and
173 ± 0.23 (ripe
fruit) mg/ml
DPPH assay
(methanol
extracts of stems
and roots):
87.07 ± 0.54% and
60.6 ± 0.86%,
respectively
-Carotene
linoleic acid:
72.6 ± 2.96%
NA
NA
Ozturk et al.,
2007
Tepe et al., 2006
food and bioproducts processing 8 9 ( 2 0 1 1 ) 217–233
S. No.
food and bioproducts processing 8 9 ( 2 0 1 1 ) 217–233
dant activity of the bitter gourd extracts of the green
fruit (79.9 ± 0.70 mg/ml) was greater than the activity of
the extracts of the leaf (63.9 ± 0.71 mg/ml), the ripe fruit
(59.0 ± 0.44 mg/ml) and the stem (36.2 ± 0.59 mg/ml). The FRAP
value for the extracts of the leaf was the greatest with
433 ± 0.007 mol FeSO4 /g dry sample, followed by the extracts
of the green fruit (43.8 ± 0.008 mol FeSO4 /g dry sample), the
stem (39 ± 0.008 mol FeSO4 /g dry sample) and the ripe fruit
(9.41 ± 0.007 mol FeSO4 /g dry sample). The antioxidant activity was greatest in the leaf, followed, in decreasing order, by
the green fruit, the stem and the ripe fruit. The TPC of the leaf
extract was 474 ± 0.71, the green fruit extract was 324 ± 1.63,
the stem extract was 259 ± 1.20 and the ripe fruit extract was
224 ± 0.86, all in units of mg GAE/g dry sample.
In the four analysed fractions, seven phenolic compounds
were identified: p-coumeric acid, tannic acid, benzoic acid, ferulic acid, gallic acid, caffeic acid and (+)-catechin. Gallic acid
was the most predominant of the phenolic compounds in all
parts of the bitter gourd, contributing from 72.8 mg/l in the
extracts of the stem to 202 mg/l in the extracts of the ripe
fruit. Caffeic acid was most concentrated in the leaf extract
(7.77 ± 1.02 mg/l), while p-coumeric acid was most abundant
in the stem extract (6.73 ± 0.21 mg/l). Ferulic acid was only
found in the stem and green fruit extracts, while benzoic acid
was not present in either the leaf or the stem extracts. The
bitter gourd fractions are rich in phenolics and have strong
antioxidant activity and radical scavenging action by all of
the testing methods (Kubola and Siriamornpun, 2008). Semiz
and Sen (2007) have studied the fruit extract of M. Charantia in
rats (200 mg/kg of weight) and found that there is a significant
increase in the activity of the hepatic antioxidant enzymes,
including SOD, catalase and glutathione peroxidase.
3.18.
Rheum ribes L
Rhubarb (Rheum ribes L.) belongs to the family Polygonaceae. It
is used for medicinal purposes, and its fresh stems and petioles are also consumed as a vegetable. It is commonly found
in eastern Turkey, Lebanon and Iran. In Turkey, 11,700 types of
plants are available, of which nearly a thousand have aromatic
and medicinal value. R. ribes is the only Rheum species growing in Turkey. Rhubarb roots have been used as a laxative and
an antipsoriatic drug in Iran (Shokravi and Agha Nasiri, 1997).
The roots of the species are also used to treat diabetes, hypertension, obesity and diarrhoea (Abu-Irmaileh and Afifi, 2003;
Tabata et al., 1994). The young shoots and petioles of R. ribes
are used against diarrhoea and as a stomachic and antiemetic
treatment.
The medicinal properties of this species are due to its
anthroquinone content. It was found using the -carotene
bleaching method that the chloroform extracts of the roots
at concentrations of 50 and 100 g/ml (91.09 ± 0.8% and
93.14 ± 1.17%, respectively) were more active than the same
concentrations of quercetin (86.11 ± 1.09% and 86.21 ± 1.10%,
respectively). Furthermore, the DPPH assay showed that
methanol extracts of both the stems and the roots exhibited higher activity than BHT at concentrations greater than
50 g/ml. The methanol extract of the stems showed the highest DPPH radical scavenging activity among all of the extracts
tested (87.07 ± 0.54%), followed by the methanol extract of the
roots (60.60 ± 0.86%) and the chloroform extract of the roots
(50.87 ± 0.3%) at a concentration of 100 g/ml.
In addition, the chloroform extract of the roots
(48.66 ± 1.23 g PEs/mg extract) had a higher phenolic content
229
than the other extracts, and the extract containing the lowest
quantity of phenolics was the chloroform extract of the stems
(22.68 ± 1.10 g PEs/mg extract). The most flavonoid-rich
extract was found to be the chloroform extract of the roots
(145.59 ± 0.22 g QEs/mg extract), while the methanol extract
of the stems (13.66 ± 0.75 g QEs/mg extract) had the lowest
flavonoid content (Ozturk et al., 2007).
3.19.
Pelargonium endlicherianum
Pelargonium endlicherianum is commonly found in Turkey and
has biological activities including antimicrobial, antifungal,
anti-inflammatory and analgesic activities.
In this study, the P. endlicherianum extract exerted a twofold greater antioxidant activity (IC50 = 7.43 ± 0.47 g/ml) than
the synthetic antioxidant BHT (18.0 ± 0.4 g/ml). In the carotene/linoleic acid test system, P. endlicherianum exhibited
a 72.6 ± 2.96% inhibition rate (Tepe et al., 2006). The results of
this study support the use of P. endlicherianum as an additive
in food and as a traditional medicine for anti-aging remedies.
The Germplasm Resources Information Network (GRIN),
maintained by the United States Department of Agriculture
(USDA), was used to obtain information about the distribution of these potent medicinal species from around the world.
Although some of the species are also available in other
parts of the world, the major distribution of these species
is presented in Table 1. Table 2 shows a comparison of the
antioxidant potential, extraction methods and chemical composition of these species.
4.
Conclusion
This review discussed medicinally significant plant species
from around the world and showed that many have high
antioxidant activity when compared to synthetic antioxidants. In addition, many of these species have a high phenolic
content and a large amount of flavonoids and flavonols. However, an overall ranking of the antioxidant strength of these
species cannot be determined because of the different experimental methods used in various studies.
We have focused on plants belonging to several different families from around the world to understand their
therapeutic uses and their potential antioxidant activities.
Unfortunately, most of the species that are claimed to contain potent antioxidant activity have not been studied in vivo.
Screening with in vitro assays has little meaning if there
is no clear evidence of the effectiveness of the extracts in
vivo. Therefore, further in vivo studies of these species are
required, and a systematic investigation of these antioxidantrich species is needed before they can be used in the food
processing industry and as preventive medicine.
Acknowledgements
The authors wish to acknowledge the financial support of
MOSTI Malaysia. This work was carried out under e-science
grant number SCF0049-IND-2007.
References
Abu-Irmaileh, B.E. and Afifi, F.U., 2003, Herbal medicine in Jordan
with special emphasis on commonly used herbs. J
Ethnopharmacol, 89: 193–197.
230
food and bioproducts processing 8 9 ( 2 0 1 1 ) 217–233
Aguilar, J.L., Rojas, P., Marcelo, A., Plaza, A., Bauer, R., Reininger,
E., Klaas, C.A. and Merfort, I., 2002, Anti-inflammatory activity
of two different extracts of Uncaria tomentosa (Rubiaceae). J
Ethnopharmacol, 81: 271–276.
Ali, S.S., Kasoju, N., Luthra, A., Singh, A., Sharanabasava, H.,
Sahu, A. and Bora, U., 2008, Indian medicinal herbs as sources
of antioxidants. Food Res Int, 41: 1–15.
Ao, C., Li, A., Elzaawely, A.A., Xuan, T.D. and Tawata, S., 2008,
Evaluation of antioxidant and antibacterial activities of Fiscus
microcarpa L. fil. extract. Food Control, 19: 940–948.
Arouma, O.I., Grootveld, M. and Halliwell, B., 1987, The role of
iron in ascorbate-dependent deoxyribose degradation. J Inorg
Biochem, 29: 289–299.
Aruoma, O.L., 1998, Free radicals, oxidative stress and
antioxidants in human health and disease. J Am Oil Chem, 75:
199–212.
Atmani, D., Chaher, N., Berboucha, M., Ayouni, K., Lounis, H.,
Boudaoud, H., Debbache, N. and Atmani, D., 2009, Antioxidant
capacity and phenol content of selected Algerian medicinal
plants. Food Chem, 112: 303–309.
Baltrusaityte, V., Venskutonis, P.R. and Ceksteryte, V., 2007,
Radical scavenging activity of different floral origin honey and
beebread phenolic extracts. Food Chem, 101: 502–514.
Beauchamp, C. and Fridovich, I., 1971, Superoxide dismutase:
improved assay and an assay applicable to polyacrylamide
gels. Anal Biochem, 44: 276–287.
Benzie, I.F.F. and Strain, J.J., 1996, The ferric reducing ability of
plasma (FRAP) as a measure of antioxidant power: The FRAP
assay. Anal Biochem, 239: 70–76.
Benzie, I.F.F. and Szeto, Y.T., 1999, Total antioxidant capacity of
teas by the ferric reducing/antioxidant power assay. J Agric
Food Chem, 47: 633–636.
Bhatia, S., Shukla, R., Madhu, S.V., Gambhir, J.K. and Prabhu, K.M.,
2003, Antioxidant status, lipid peroxidation and NO end
products in patients of type 2 diabetes mellitus with
nephropathy. Clin Biochem, 36: 557–562.
Blois, M.S., 1958, Antioxidant determinations by the use of a
stable free radical. Nature, 181: 1199–1200.
Brand-Williams, W., Cuvelier, M.E. and Berset, C., 1995, Use of a
free radical method to evaluate antioxidant activity. J Food Sci
Technol, 28: 25–30.
Butler, L.G., Price, M.L. and Brotherton, J.E., 1982, Vanillin assay
for proanthocyanidins (condensed tannins): Modification of
the solvent for estimation of the degree of polymerization. J
Agric Food Chem, 30: 1087–1089.
Cai, Y., Luo, Q., Sun, M. and Corke, H., 2004, Antioxidant activity
and phenolic compounds of 112 traditional Chinese medicinal
plants associated with anticancer. Life Sci, 74: 2157–2184.
Campos, A. and Lissi, E., 1996, Kinetics of the reaction between
2,2-azinobis-3-ethyl benzthiazoline-sulfonic acid (ABTS)
derived radical cations and phenols. Inter J Chem Kinet, 29:
219–224.
Cervellati, R., Renzulli, C., Guerra, M.C. and Speroni, E., 2002,
Evaluation of antioxidant activity of some natural
polyphenolic compounds using the Briggs-Rauscher reaction
method. J Agric Food Chem, 50: 7504–7509.
Chiang, H., Lo, Y. and Lu, F., 1993, Xanthine oxidase inhibitors
from the leaves of Alsophila Spinulosa (Hook) Tryon. J Enzym
Inhib, 8(1): 61–71.
Chiang, Y., Chang, J., Kuo, C., Chang, C. and Kuo, Y., 2005,
Cytotoxic triterpenes from the aerial roots of Ficus microcarpa.
Phyto Chem, 66: 495–501.
Chiang, Y.M., Chaung, D.Y., Wang, S.Y., Kuo, Y.H., Tsai, P.W. and
Shyur, L.F., 2004, Metabolite profiling and chemopreventive
bioactivity of plant extracts from Bidens pilosa. J
Ethnopharmacol, 95: 409–419.
Chryssavgi, G., Vassiliki, P., Athanasios, M., Kibouris, T. and
Michael, K., 2008, Essential oil composition of Pistacia lentiscus
L. and Myrtus communis L.: Evaluation of antioxidant
capacity of methanolic extracts. Food Chem, 107: 1120–1130.
Chung, K.T., Wong, T.Y., Huang, Y.W. and Lin, Y., 1998, Tannins
and human health: A review. Crit Rev Food Sci Nutr, 38:
421–464.
Chung, S., Osawa, T. and Kawakishi, S., 1997, Hydroxyl radical
scavenging effects of spices and scavengers from Brown
Mustard (Brassica nigra). Biosci Biotechnol Biochem, 61(1):
118–123.
Cotelle, N., Bernier, J.L., Catteau, J.P., Pommery, J., Wallet, J.C. and
Gaydou, E.M., 1996, Antioxidant properties of
hydroxy-flavones. Free Radical Biol Med, 20: 35–43.
Dai, G.H., Andary, C., Mondolot, L. and Boubals, D., 1995,
Involvement of phenolic compounds in the resistance of
grapewine callus to downy mildew (Plasmopara viticola). Eur J
Plant Pathol, 101: 541–547.
Dall’ Acqua, S., Cervellati, R., Loi, M.C. and Innocenti, G., 2008,
Evaluation of in vitro antioxidant properties of some
traditional Sardinian medicinal plants: Investigation of the
high antioxidant capacity of Rubus ulmifolius. Food Chem, 106:
745–749.
Dastmalchi, K., Dorman, H.J.D., Kosar, M. and Hiltunen, R., 2007,
Chemical composition and in vitro antioxidant evaluation of a
water soluble extract of Moldavian balm (Dracocephalum
moldavica L.) extract. Food Sci Technol, 40(2): 232–248.
Deba, F., Xuan, T.D., Yasuda, M. and Tawata, S., 2008, Chemical
composition and antioxidant, antibacterial and antifungal
activities of the essential oils from Bidens pilosa Linn. var.
Radiata. Food Control, 19: 346–352.
Del Bano, M.J., Lorente, J., Castillo, J., Benavente-garcia, O., Rio,
J.A., Ortuno, A., Quirin, K.W. and Gerard, D., 2003, Phenolic
diterpenes, flavones, and rosmarinic acid distribution during
the development of leaves, flowers, stems and roots of
Rosmarinus officinalis antioxidant activity. J Agric Food Chem,
51(15): 4247–4253.
Deschmarchelier, C., Mongolli, E., Coussio, J. and Ciccia, G., 1997,
Evaluation of the in vitro antioxidant activity in extracts of
Uncaria tomentosa (Willd.) DC. Phytother Res, 11:
254–256.
Di Matteo, V. and Esposito, E., 2003, Biochemical and therapeutic
effects of antioxidants in the treatment of Alzheimer’s
disease, Parkinson’s disease, and amyotrophic lateral
sclerosis. Curr Drug Targets CNS Neurol Disord, 2: 95–107.
Dimo, T., Rakotonirina, S.V., Tan, P.V., Azay, J., Dongo, E. and Cros,
G., 2002, Leaf methanol extract of Bidens pilosa prevents and
attenuates the hypertension induced by high-fructose diet in
Wistar rats. J Ethnopharmacol, 83: 183–191.
Djeridane, A., Yousfi, M., Nadjemi, B., Boutassouna, D., Stocker, P.
and Vidal, N., 2006, Antioxidant activity of some Algerian
medicinal plants extracts containing phenolic compounds.
Food Chem, 97(4): 654–660.
Dragland, S., Senoo, H., Wake, K., Holte, K. and Blomhoff, R., 2003,
Several culinary and medicinal herbs are important sources of
dietary antioxidants. J Nutr, 133: 1286–1290.
El Batran, S.A.E.S., El-Gengaihi, S.E. and El Shabrawya, O.A., 2006,
Some toxicological studies of Momordica charantia L. on albino
rats in normal and alloxan diabetic rats. J Ethnopharmacol,
108: 236–242.
Falkiewicz, B. and Lukasiak, J., 2001, Vilcacora (Uncaria tomentosa
(Willd.) DC. and Uncaria guianensis (Aublet) Gmell.)—A review of
published scientific literature. Case Rep Clin Pract Rev, 2:
305–316.
Garai, S. and Mahato, S.B., 1997, Isolation and structure
elucidation of three triterpenoid saponins from Acacia
auriculiformis. Phytochemistry, 44: 137–140.
Gerber, M., Boutron-Ruault, M.C., Hercberg, S., Riboli, E., Scalbert,
A. and Siess, M.H., 2002, Food and Cancer: state of the art
about the protective effect of fruits and vegetables. Bull
Cancer, 89: 293–312.
Ghosh, M., Babu, S.P.S. and Sukul, N.C., 1993, Antifilarial effect of
two triterpenoid saponins isolated from Acacia auriculiformis.
Indian J Exp Biol, 31: 604–606.
Grice, H.P., 1988, Enhanced tumour development by butylated
hydroxyanisole (BHA) from the prospective of effect on
forestomach and oesophageal squamous epithelium. Food
Chem Toxicol, 26: 717–723.
Gulcin, I., Kufrevioglu, O.I., Oktay, M. and Buyukokuroglu, M.E.,
2004, Antioxidant, antimicrobial, antiulcer and analgesic
food and bioproducts processing 8 9 ( 2 0 1 1 ) 217–233
activities of nettle (Urtica dioica L.). J Ethnopharmacol, 90:
205–215.
Hagerman, A.E. and Butler, L.G., 1978, Protein precipitation
method for the quantitative determination of tannins. J Agric
Food Chem, 26: 809–812.
Halliwell, B., Gutteridge, J.M. and Aruoma, O.I., 1987, The
deoxyribose method: a simple test tube assay for
determination of rate constants for reaction of hydroxyl
radicals. Anal Biochem, 165: 215–219.
Hasani, P., Yasa, N., Vosough-Ghanbari, S., Mohammadirad, A.,
Dehghan, G. and Abdollahi, M., 2007, In vivo antioxidant
potential of Teucrium polium as compared to ␣-tocopherol.
Acta Pharm, 57: 123–129.
Hatano, T., Kagawa, H., Yasuhara, T. and Okuda, T., 1988, Two new
flavonoids and other constituents in licorice root; their
relative astringency and radical scavenging effects. Chem
Pharm Bull, 36: 2090–2097.
Heitzman, M.E., Neto, C.C., Winiarz, E., Vaisberg, A.J. and
Hammond, G.B., 2005, Ethnobotany, Phytochemistry and
Pharmacology of Uncaria (Rubiaceae). Phytochemistry, 66:
5–29.
Huang, D., Ou, B., Hampsch-Woodill, M.F., Judith, A. and Prior,
R.L., 2002, High-throughput assay of oxygen radical
absorbance capacity (ORAC) using a multichannel liquid
handling system coupled with a microplate fluorescence
reader in 96-well format. J Agric Food Chem, 50: 4437–4444.
Ivancheva, S., Manolova, N., Serkedjieva, J., Dimov, V. and
Ivanovska, N., 1992, Polyphenols from Bulgarian medicinal
plants. Basic Life Sci, 59: 717–728.
Jodynis-Liebert, J., Murias, M. and Bolszyk, E., 1999, Effect of
several sesquiterpene lactons on lipid peroxidation and
glutathione level. Planta Med, 65: 320–324.
Kaur, K., Arora, S., Hawthorne, M.E., Kaur, S., Kumar, S. and
Mehta, R.G., 2002, Correlative study of antimutagenic and
chemopreventive activity of Acacia auriculiformis A. cunn. and
Acacia nilotica (L.) Willd Ex Del. Drug Chem Toxicol, 25: 39–63.
Kaur, K., Micheal, M., Arora, S., Harkonen, P. and Kumar, S., 2005,
In vitro bioactivity guided fractionation and characterization
of polyphenolic inhibitory fractions from Acacia nilotica (L)
Willd Ex Del. J Ethnopharmacol, 99: 353–360.
Keplinger, K., Laus, G., Wurm, M., Dierich, M.P. and Teppner, H.,
1999, Uncaria tomentosa (Willd.) DC.-ethnomedicinal use and
new pharmacological, toxicological and botanical results. J
Ethnopharmacol, 64: 23–24.
Kirby, A.J. and Schmidt, R.J., 1997, The antioxidant activity of
Chinese herbs for eczema and of placebo herbs. J
Ethnopharmacol, 56: 103–108.
Knekt, P., Jarvinen, R., Reunanen, A. and Maatela, J., 1996,
Flavonoid intake and coronary mortality in Finland: A cohort
study. Brit Med J, 312: 478–481.
Koleva, I.I., Van Beek, T.A., Linssen, J.P.H., de Groot, A. and
Evstatieva, L.N., 2002, Screening of plant extracts for
antioxidant activity: A comparative study on three testing
methods. Phytochem Anal, 13(1): 8–17.
Krasowska, A., Rosiak, D., Szkapiak, K., Oswiecimska, M., Witek,
S. and Lukaszewicz, M., 2001, The antioxidant activity of BHT
and new phenolic compounds PYA and PPA measured by
chemiluminescence. Cell Mol Biol Lett, 6: 71–81.
Kubola, J. and Siriamornpun, S., 2008, Phenolic contents and
antioxidant activities of bitter gourd (Momordica charantia L.)
leaf, stem and fruit extracts in vitro. Food Chem, 110: 881–890.
Kumari, A. and Kakkar, P., 2008, Screening of antioxidant
potential of selected barks of Indian medicinal plants by
multiple in vitro assays. Biomed Environ Sci, 21(1):
24–29.
Kuo, Y.H. and Li, Y.C., 1997, Constituents of the bark of Ficus
microcarpa L.f. J Chin Chem Soc, 44: 321–325.
Lamaison, J.L., Petitjean-Freytet, C. and Carnat, A., 1991,
Medicinal Lamiaceae with antioxidant properties, a potential
source of rosamarinic acid. Pharm Acta Helv, 66: 185–188.
Lattif, A.G., Omar, I.M., Said, I.M. and Kadri, A., 1984, A
multi-variate approach to the study of medicinal plants in
Malaysia. J Sing Nat Acad Sci, 13: 101–105.
231
Lau, K.M., He, Z.D., Dong, H., Fung, K.P. and But, P.P.H., 2002,
Antioxidative, anti-inflammatory and hepato-protective
effects of Ligustrum robustum. J Ethnopharmacol, 83: 63–71.
Lefer, D.J. and Granger, D.N., 2000, Oxidative stress and cardiac
disease. Am J Med, 109: 315–323.
Leontowicz, H., Gorinstein, S., Lojek, A., Leontowicz, M., Ciz, M.
and Soliva-Fortuny, R., 2002, Comparative content of some
bioactive compounds in apples, peaches and pears and their
influence on lipids and antioxidant capacity in rats. J Nutr
Biochem, 13: 603–610.
Li, H., Wong, C., Cheng, K. and Chen, F., 2008, Antioxidant
properties in vitro and total phenolic contents in methanol
extracts from medicinal plants. Swiss Soc Food Sci Technol,
41: 385–390.
Lima, C.F., Andrade, P.B., Seabra, R.M., Fernandes-Ferreira, M. and
Pereira-Wilson, C., 2005, The drinking of a Salvia officinalis
infusion improves liver antioxidant status in mice and rats. J
Ethnopharmacol, 97(2): 383–389.
Lima, C.F., Valentao, P.C.R., Andrade, P.B., Seabra, R.M.,
Fernandes-Ferreira, M. and Pereira-Wilson, C., 2007, Water
and methanolic extracts of Salvia officinalis protect HepG2 cells
from t-BHP induced oxidative damage. Chem Biol Interact,
167: 107–115.
Lissi, E., Pascual, C. and del Castillo, M., 1992, Luminol
luminescence induced by 2,2′ -azo-bis(2-amidinopropane)
thermolysis. Free Radic Res Commun, 17: 299–311.
Ljubuncic, P., Dakwar, S., Portnaya, I., Cogan, U., Azaizeh, H. and
Bomzon, A., 2006, Aqueous extracts of Teucrium polium possess
remarkable antioxidant activity in vitro. Evid based
Complement Alternat Med, 3(3): 329–338.
Lyckander, I.M. and Malterud, K.E., 1992, Lipophilic flavonoids
from Orthosiphon spicatus as inhibitors of 15-lipoxygenase.
Acta Pharm Nordica, 4: 159–166.
Mackeen, M.M., Ali, A.M., Lajis, N.H., Kawazu, K., Hassan, Z.,
Amran, M., Habsah, M., Mooi, L.Y. and Mohamed, S.M., 2000,
Antimicrobial, antioxidant, antitumour-promoting and
cytotoxic activities of different plant part extracts of Garcinia
atroviridis Griff. ex. T. Anders. J Ethnopharmacol, 72:
395–402.
Maiga, A., Malterud, K.E., Diallo, D. and Paulsen, B.S., 2006,
Antioxidant and 15-lipoxygenase inhibitory activities of the
Malian medicinal plants Diospyros abyssinica (Hiern) F. White
(Ebenaceae), Lannea Velutina A. Rich (Anacardiaceae) and
Crossopteryx febrifuga (Afzel) Benth. (Rubiaceae). J
Ethnopharmacol, 104: 132–137.
Mallavadhani, U.V., Panda, A.K. and Rao, Y.R., 1998, Pharmacology
and chemotaxonomy of Diospyros. Phytochemistry, 49:
901–951.
Mantle, D., Eddeb, F. and Pickering, A.T., 2000, Comparison of
relative antioxidant activities of British medicinal plant
species in vitro. J Ethnopharmacol, 72: 47–51.
Masude, T., Isibe, D., Jitoe, A. and Naramati, N., 1992, Antioxidant
curcuminoids from rhizomes of Curcuma zanthorrhiza.
Phytochemistry, 33: 3645–3647.
Matkowski, A. and Piotrowska, M., 2006, Antioxidant and free
radical scavenging activities of some medicinal plants from
the Lamiaceae. Fitoterapia, 77: 346–353.
Matkowski, A., 2008, Plant in vitro culture for the production of
antioxidants - A Review. Biotechnol Adv, 26(6): 548–560.
Maulik, G., Maulik, N., Bhandarp, V., Kagan, V., Pakrashi, S. and
Das, D.K., 1997, Evaluation of antioxidant effectiveness of a
few herbal plants. Free Radical Res, 27: 221–228.
Miller, H.M., 1971, A simplified method for the evaluation of
antioxidants. J Am Oil Chem Soc, 45: 91.
Moreno, M.I.N., Isla, M.I., Sampietro, A.R. and Vattuone, M.A.,
2000, Comparison of the free radical scavenging activity of
propolis from several regions of Argentina. J Ethnopharmacol,
71: 109–114.
Murzakhmetova, M., Moldakarimov, S., Tancheva, L., Abarova, S.
and Serkedjieva, J., 2008, Antioxidant and prooxidant
properties of a polyphenol-rich extract from Geranium
sanguineum L. in vitro and in vivo. Phytother Res, 22(6):
746–751.
232
food and bioproducts processing 8 9 ( 2 0 1 1 ) 217–233
Navarro, M.C., Montilla, M.P., Martin, A., Jimenez, J. and Utrilla,
M.P., 1992, Free radicals and hypototoxic activity of
Rosemarinus tomentosus. Planta Med, 59: 312–314.
Nishimiki, M., Appaji, N. and Yagi, K., 1972, The occurrence of
superoxide anion in the reaction of reduced phenazine
mehosulphate and molecular oxygen. Biochem Biophys, 46:
849–854.
Ohkawa, H., Ohishi, N. and Yagi, K., 1979, Assay for lipid peroxide
in animal tissues by thiobarbituric acid reaction. Anal
Biochem, 95: 351–358.
Osawa, T. and Namiki, M., 1981, A novel type of antioxidant
isolated from leaf wax of Eucalyptus leaves. Agric Biol Chem,
45(3): 735–739.
Ou, B., Hampsch-Woodill, M. and Prior, R.L., 2001, Development
and validation of an improved oxygen radical absorbance
capacity assay using fluorescein as the fluorescent probe. J
Agric Food Chem, 49: 4619–4626.
Oyaizu, M., 1986, Studies on product of browing effect reaction
prepared from glucose amine. J Nutr, 44: 307–315.
Ozturk, M., Aydogmus-Ozturk, F., Duru, M.E. and Topcu, G., 2007,
Antioxidant activity of stem and root extracts of Rhubarb
(Rheum ribes); An edible medicinal plant. Food Chem, 103:
623–630.
Parkashi, A., Ray, H., Pal, B.C. and Mahato, S.B., 1991, Sperm
immobilizing effect of triterpene saponins from Acacia
auriculiformis. Contraception, 43: 475–483.
Peuchant, E., Brun, J., Rigalleau, V., Dubourg, L., Thomas, M. and
Daniel, J., 2004, Oxidative and antioxidative status in pregnant
women with either gestational or type 1 Diabetes. Clin
Biochem, 37: 293–298.
Pilarski, R., Zielinski, H., Ciesiolka, D. and Gulewicz, K., 2006,
Antioxidant activity of ethanolic and aqueous extracts of
Uncaria tommentosa (Willd.) DC. J Ethnopharmacol, 104:
18–23.
Povilaityte, V. and Venskutonis, P.R., 2000, Investigation of
antioxidative activity of purple peril (Perilla frutescens L.),
Moldavian dragonhead (Dracocephalum moldavica L.) and
Roman chamomile (Anthemis nobilis L.) extracts in rapeseed oil. J
Am oil Chem Soc, 77(7): 951–956.
Povilaityte, V., Cuvelier, M.E. and Berset, C., 2001, Antioxidant
properties of Moldavian dragonhead (Dracocephalum moldavica
L.). J Food Lipids, 8(1): 45–64.
Ramos, A., Rivero, R., Victoria, M.C., Visozo, A., Piloto, J. and
Garcia, A., 2001, Assessment of mutagenicity in Parthenium
hysterophorus L. J Ethnopharmacol, 77: 25–30.
Ravikumar, Y.S., Mahadevan, K.M., Kumaraswmay, M.N., Vaidya,
V.P., Manjunatha, H., Kumar, V. and Satyanarayana, N.D., 2008,
Antioxidant cytotoxic and genotoxic evaluation of alcoholic
extract of Polyalthia cerasoides (Roxb.) Bedd. Environ Toxicol
Pharmacol, 26: 142–146.
Re, R., Pelligrini, N., Proteggente, A., Pannala, A., Yang, M. and
Rice-Evans, C.A., 1999, Antioxidant activity applying an
improved ABTS radical cation decolorization assay. Free
Radical Biol Med, 26: 1231–1237.
Rechinger, H., (1986). Flora Iranica Labiatae (Graz, Akademische
Druck Verlagsantalt, Austria), pp. 218–230
Recio, M.C., Giner, R.M., Manez, S., Gueho, J., Julien, H.R.,
Hostettmann, K. and Rios, J.L., 1995, Investigations on the
steroidal anti-inflammatory activity of triterpenoids from
Diospyros leucomelas. Planta Med, 61: 9–12.
Rice-Evans, C. and Miller, N.J., 1994, Total antioxidant status in
plasma and body fluids. Methods Enzymol, 234: 279–293.
Rice-Evans, C., Miller, N.J. and Paganga, G., 1996, Structure
antioxidant activity relationship of flavonoids and phenolic
acids. Free Radical Biol Med, 20: 933–956.
Ruch, R.J., Cheng, S.J. and Klaunig, J.E., 1989, Prevention of
cytotoxicity and inhibition of intercellular communication by
antioxidant catechins isolated from Chinese green tea.
Carcinogen, 10: 1003–1008.
Saha, K., Lajis, N.H., Israf, D.A., Hamzah, A.S., Khozira, S.,
Khamis, S. and Syahida, A., 2004, Evaluation of antioxidant
and nitric oxide inhibitory activities of selected Malaysian
medicinal plants. J Ethnopharmacol, 92: 263–267.
Sakanaka, S., Tachibana, Y. and Okada, Y., 2005, Preparation and
antioxidant properties of extracts of Japanese persimmon leaf
tea (kakinoha-cha). Food Chem, 89: 569–575.
Salah, N., Miller, N.J., Paganga, G., Tijburg, L., Bolwell, G.P. and
Rice-Evans, C.A., 1995, Polyphenolic flavanols of aqueous
phase radicals and as chain-breaking antioxidants. Arch
Biochem Biophys, 322: 339–345.
Semiz, A. and Sen, A., 2007, Antioxidant and chemoprotective
properties of Momordica charantia L. (bitter melon) fruit extract.
Afr J Biotechnol, 6(3): 273–277.
Serkedjieva, J. and Manolova, N., 1992, Plant polyphenol complex
inhibits the reproduction of influenza and herpes simplex
viruses. Basic Life Sci, 59: 705–715.
Shahidi, F., Janitha, P.K. and Wanasundara, P.D., 1992, Phenolic
antioxidants. Crit Rev Food Sci Nutr, 32: 67–103.
Sharififar, F., Dehghn-Nudeh, G. and Mirtajaldini, M., 2009, Major
flavonoids with antioxidant activity from Teucrium polium L.
Food Chem, 112: 885–888.
Shokravi, A. and Agha Nasiri, K., 1997, Synthesis of 1,2,3,4,5,6,7,8octahydro-9-ethoxy-10-hydroxy-1-anthracenone (OEHA). Iran
J Chem Chem Eng, 16: 10–15.
Siddhuraju, P. and Becker, K., 2003, Studies on antioxidant
activities of mucana seed (Mucuna pruriens var utilis) extract
and various nonprotein amino/imino acids through in vitro
models. J Food Sci Agric, 83: 1517–1524.
Sies, H., 1993, Strategies of antioxidant defense. Eur J Biochem,
215: 213–219.
Silva, E.M., Souza, J.N.S., Rogez, H., Rees, J.F. and Larondelle, Y.,
2007, Antioxidant activities and polyphenolic contents of
fifteen selected plant species from the Amazonian region.
Food Chem, 101: 1012–1018.
Singh, R., Singh, S., Kumar, S. and Arora, S., 2004, Hydroxyl
radical scavenging potential of acetone extract/fractions of
Acacia nilotica (L.). Willd Ex Del. Int J Biosci Rep, 2: 440–446.
Singh, R., Singh, S., Kumar, S. and Arora, S., 2007, Evaluation of
antioxidant potential of ethyl acetate extract/fractions of
Acacia auriculiformis A. Cunn. Food Chem Technol, 45:
1216–1223.
Singleton, V.L. and Rossi, J.A., 1965, Colorimetry of total phenolics
with phosphomolybdic-phosphotungstic acid reagents. Am J
Enol Viticult, 16: 144–158.
Singleton, V.L., Orthofer, R. and Lamuela-Raventos, R.M., 1999,
Analysis of total phenols and other oxidation substrates and
antioxidants by means of Folin-Ciocalteu reagent. Oxid
Antioxid, 299: 152–178.
Slinkard, K. and Singleton, V.L., 1977, Total phenol analyses:
automation and comparison with manual methods. Am J Enol
Viticult, 28: 49–55.
Smith, M.A., Rottkamp, C.A., Nunomura, A., Raina, A.K. and Perry,
G., 2000, Oxidative stress in Alzheimer’s disease. Biochem
Biophys Acta, 1502: 139–144.
Sokmen, M., Angelova, M., Krumova, E., Pashova, S., Ivancheva,
S., Sokmen, A. and Serkedjieva, J., 2005, In vitro antioxidant
acitivity of polyphenol extracts with antiviral properties from
Geranium sanguineum L. Life Sci, 76: 2981–2993.
Speroni, E. and Scartezzini, P., 2000, Review on some plants of
Indian traditional medicine with antioxidant activity. J
Ethnopharmacol, 71: 23–43.
Sreejayan, N. and Rao, M., 1996, Free radical scavenging activity
of Curcuminoids. Drug Res, 46: 169–171.
Srinivasan, G.V., Ranjith, C. and Vijayan, K.K., 2008, Identification
of chemical compounds from the leaves of Leea indica. Acta
Pharm, 58(2): 207–214.
Steer, P., Milligard, J., Sarabi, D.M., Wessby, B. and Kahan, T., 2002,
Cardiac and vascular structure and function are related to
lipid peroxidation and metabolism. Lipids, 37: 231–236.
Tabata, M., Sezik, E., Honda, G., Yesilada, E., Fuki, H. and Goto, K.,
1994, Traditional medicine in Turkey III. Folk medicine in East
Anatolia, van and Bitlis provinces. Int J Pharmacogn, 32: 3–12.
Tepe, B., Sokmen, M., Akpulat, H.A., Yumrutas, O. and Sokmen,
A., 2006, Screening of antioxidative properties of the
methanolic extracts of Pelargonium endlicherianum Fenzl.,
Verbascum wiedemannianum Fisch. and Mey., Sideritis libanotica
food and bioproducts processing 8 9 ( 2 0 1 1 ) 217–233
Labill. Subsp. lineraris (Bentham) Borm., Centaurea mucronifera
DC. and Hieracium cappadocicum Freyn from Turkish flora. Food
Chem, 98: 9–13.
Trouillas, P., Calliste, C.A., Allais, D.P., Simon, A., Marfak, A.,
Delage, C., et al., 2003, Antioxidant, anti-inflammatory and
antiproliferative properties of sixteen water plant extracts
used in the Limousin countryside as herbal teas. Food Chem,
80: 399–407.
Uchida, K., 2000, Role of reactive aldehyde in cardiovascular
diseases. Free Radical Biol Med, 28: 1685–1696.
Vander Jagt, T.J., Ghattas, R., Vander Jagt, D.J., Crossey, M. and
Glew, R.H., 2002, Comparison of the total antioxidant content
of 30 widely used medicinal plants of New Mexico. Life Sci, 70:
1035–1040.
Vinson, J.A., Hao, J., Su, X. and Zubik, L., 1998, Phenol antioxidant
quantity and quality in foods: vegetables. J Agric Food Chem,
46: 3630–3634.
Virdi, J., Sivakami, S., Shahani, S., Suthar, A.C., Banavalikar, M.M.
and Biyani, M.K., 2003, Antihyperglycemic effects of three
extracts from Momordica charantia. J Ethnopharmacol, 88:
107–111.
233
Wang, S.Y. and Lin, H.S., 2000, Antioxidant activity in fruits and
leaves of blackberry, raspberry, and strawberry varies with
cultivar and developmental stage. J Agric Food Chem, 48:
140–146.
Wichi, H.C., 1986, Safety evaluation of butylated hydroxytoluene
(BHT) in the liver, lung and gastrointestinal tract. Food Chem
Toxicol, 24: 1127–1130.
Winston, J.C., 1999, Health-promoting properties of common
herbs. Am J Clin Nutr, 70: 491–499.
Yang, H., Chen, S., Chang, N., Chang, J., Lee, M. and Tsai, P., 2006,
Protection from oxidative damage using Bidens pilosa extracts
in normal human erythrocytes. Food Chem Toxicol, 44:
1513–1521.
Yesilada, E., Honda, G., Sezik, E., Tabata, M., Goto, K. and Ikeshiro,
Y., 1993, Traditional medicine in Turkey IV. Folk medicine in
the Mediterranean subdivision. J Ethnopharmacol, 39: 31–38.
Zhong, S.M., Waterman, P.G. and Jeffreys, J.A.D., 1984,
Naphtoquinones and triterpenes from African Diospyros
species. Phytochemistry, 23: 1067–1072.