Aliyu et al., Nig. Journ. Pharm. Sci., March, 2008, Vol. 7 No. 1, P.

1– 8

Nigerian Journal of Pharmaceutical Sciences

Vol. 7, No. 1, March, 2008, ISSN: 0189-823X
All Rights Reserved

ACTIVITY OF PLANT EXTRACTS USED IN NORTHERN NIGERIAN

TRADITIONAL MEDICINE AGAINST METHICILLIN-RESISTANT
STAPHYLOCOCCUS AUREUS (MRSA)
A. B. Aliyu,1* A. M. Musa,2 M. S. Abdullahi,3 A. O. Oyewale1, U. S.Gwarzo4
1
Department of Chemistry, Ahmadu Bello University, Zaria, Nigeria
2
Department of Pharmaceutical and Medicinal Chemistry, Ahmadu Bello University, Zaria, Nigeria
3
National Research Institute for Chemical Technology, Basawa, Zaria, Nigeria
4
Department of Chemistry, Federal College of Education, Kano, Nigeria

*Author for Correspondence: babandoaliyu@yahoo.com , +2348057371917

ABSTRACT
The crude alcohol extracts obtained from 12 medicinal plants used in Northern Nigerian traditional medicine for the
treatment of various infectious diseases, were evaluated for potential antibacterial activity against 25 hospital isolates of
methicillin resistant Staphylococcus aureus (MRSA) using disc diffusion and broth dilution assays. Six methanol and
two ethanol plant extracts demonstrated activity against the isolates, with zones of inhibition ranging from 10-30 mm,
minimum inhibitory concentration (MIC) ranging from 3-5 mgmL-1 and minimum bactericidal concentration (MBC)
ranging from 4-6 mgmL-1. The potency of these extracts based on the zones of inhibition, MIC and MBC values were
higher in Acacia albida, followed by Pavetta crassipes, Boscia senegalensis and Momordica basalmina. Phytochemical
screening showed that all the extracts contain flavonoids and tannins while saponins are present in all the extracts with
exception of Acacia albida and Pavetta crassipes. The results revealed great therapeutic potentials of these plants which
might be used as adjunct in the treatment of MRSA and associated infections. Further identification of the active
constituents is needed to exploit them in evaluating efficacy and safety in vivo against MRSA.

Key words: Plant extracts, traditional medicine, Methicillin-Resistant Staphylococcus aureus.

INTRODUCTION 1960’s (Chambers, 1997), MRSA strains and

Methicillin-resistance Staphylococcus aureus coagulase-negative Staphylococci had spread
(MRSA) has been emerging world wide as worldwide. Recent reports by European
one of the most important hospital and antimicrobial research surveillance system
community acquired pathogens (Kim et al., have indicated that MRSA strains account for
2005). It is responsible for a wide range of more than 40% of all S. aureus bacteremias in
diseases, including endocarditis, the United Kingdom (EARSS, 2002). In 1999,
osteomyelitis, toxic-shock syndrome, MRSA accounted for >50% of S. aureus
pneumonia, food poisoning and carbuncles. isolates from patients in intensive care units
These infections can occur in wounds or skin, (ICUs) in the National Nosocomial Infection
burns and other sites where tubes enter the Surveillance (NNIS) system (CDC&P, 2003);
body, as well as in the eyes, bones, heart or in 2004 the proportion of MRSA isolates had
blood (Chambers, 2003). Since its first increased from 59.5% to 64.4% in ICUs in the
outbreak in European hospitals in the early United States (CDC&P, 2004; Klevens et al.,

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2006). Hospital surveillance data in 2001 has attention of phytochemists across the globe
shown that MRSA was the biggest threat in (Polombo and Semple, 2002;
China, where resistance among hospital- Voravuthikunchai and Kitpipit, 2005; Aqil, et
acquired infections reaches almost 90% al., 2006). In this study, we report the
(Zhang et al., 2006). In Nigeria, Kenya and screening of twelve (12) medicinal plants used
Cameroon, the rate of MRSA spread was in Northern Nigerian traditional medicine,
about 21-30% in 2003 (Kesah et al., 2003), against methicillin resistance Staphylococcus
however, prevalence rate of about 69% of aureus (MRSA).
MRSA isolates was obtained in a study among
healthy women in Zaria, Nigeria (Onanuga , et MATERIALS AND METHODS
al., 2005). The problem of microbial Plant materials
resistance to antibiotics is fast growing The twelve (12) medicinal plants were
particularly in the hospitals where methicillin- collected between February, 2006 and
resistant Staphylococcus aureus has become a September, 2007 at Dakace village in Zaria,
global threat to antimicrobial chemotherapy. Kaduna state, Rogo village in Kano state,
This situation seems to pose the outlook for Tsafe in Zamfara State and Funtua in Katsina
the use of antimicrobial drugs in future to be state, Northern Nigeria. The plants were
uncertain (Nascimento, et al., 2000); as a authenticated at the Herbarium unit,
result, the search for new ways to treat MRSA Department of Biological Sciences, Ahmadu
infections stimulates research into natural Bello University, Zaria. Voucher specimens
products from medicinal plants. In Northern were deposited there for future reference.
Nigerian traditional medicine, many Samples were air dried for two weeks and
indigenous plant are widely used in the pulverized to powder form using mortar and
treatment of various infectious diseases; such pestle.
plants includes Acacia albida, Anchomanes Preparation of extracts
difformis, Boscia senegalensis, Bridelia Fifty gramme of powdered sample of each
ferruginea, Ficus ingens, Indigofera arrecta, plant was extracted exhaustively (cold
Moringa oleifera, Mormodica basalmina, maceration) with methanol (and ethanol only
Pavetta crassipes, Phyllanthus amarus and on Moringa oleifera and Vernonia
Vernonia bluemoides. Many of these plants blumeoides) for 48 h. The extracts were
have records of widespread claims of filtered using Whatman filter paper no. 2, and
therapeutic effectiveness against infectious concentrated at reduced pressure to afford the
and non infectious diseases across Northern various crude extracts of the twelve plants
Nigeria, West Africa and beyond (Burkill, samples. The samples were kept in the
1995). Plants extracts or their active principles refrigerator at 5°C before use.
have enormous therapeutic potentials (Iwu et Phytochemical screening
al., 1999) and the continued investigation of The extract was subjected to various
their secondary metabolites has led to phytochemical tests to identify the chemical
important breakthrough in pharmacology and constituent present using standard methods as
has helped tremendously in the development described by Sofowora (1993) and Trease and
of modern pharmacotherapeutics in Africa and Evans (1989).
other part of the world (Doerge, et al., 1971; Bacterial culture
Nwaogu, et al., 2007). In recent times, The MRSA strains used in this study were
research interest for active chemical agents clinical isolates from urethral swab, seminal
against MRSA, especially from indigenous fluid, urine, high virginal swab, blood, skin
medicinal plants resources has received the and sputum of patients presenting with

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symptoms of S. aureus-associated diseases. growth of the broth. The minimum

The isolates were identified by standard bactericidal concentration (MBC) was
method (Cowan and Steel, 1993). All S. however, determined by aseptically
aureus isolates were tested for methicillin inoculating aliquots of culture from all MIC
resistance. The disc diffusion method outlined tubes on sterile nutrient agar plates and
by the National Committee of Clinical incubating at 37°C for 48 h. MBCs were
laboratory standard (NCCLS) (1993) was used recorded as the lowest concentration of
with 1 µg oxacillin disk (Oxoid). The zones of extracts showing no bacterial growth.
inhibition were measured after incubation at
35°C for 24 h. Isolates with zones diameter ≤ RESULTS
10 mm were considered methicillin resistant. Phytochemical screening
The standard strain used was S. aureus ATCC The profile of the twelve plants material used
13909. The organisms were maintained on in this study is shown in Table 1. The results
agar slope at 4°C and sub cultured for 24 h of phytochemical screening revealed the
before use. presence of flavonoids and tannins in all the
Antibacterial activity extracts, saponins was found in all the extracts
The disc diffusion assay (Lennette, 1985) was with exception of Acacia albida and Pavetta
used to screen for antibacterial activity. crassipes while anthraquinone was only found
Standard inoculum (0.5 McFarland standards) in Acacia albida and Pavetta crassipes (Table
was introduced onto the surface of the sterile 2).
Mueller Hinton Agar (MHA) plates and a Antibacterial activity
sterile glass spreader was used for even The results of the antibacterial activity
distribution over the media. Blank sterile revealed that only eight of the twelve plants
paper discs (6 mm) were placed on the extract have demonstrated activity against the
inoculated MHA surface and impregnated 25 hospital isolates of MRSA used. The
with 15µL of the extracts; this gave a activity of methanol extracts of Acacia albida
concentration 150µg disc-1. The procedure (30mm), Pavetta crassipes (22mm) and
was repeated for all the MRSA strains used. Boscia senegalensis (19mm), Mormodica
The plates were incubated at 37°C for 24 h. basalmina (15mm) were significant against
All tests were performed in duplicate and the the MRSA, Anchomanes difformis and
antibacterial activity was expressed as the Phyllantus amarus exhibited activity at
mean diameter of inhibition zones (mm) 13mm, whereas ethanol extracts of Moringa
produced by the extracts. The minimum oleifera (10mm) and Vernonia blumeoides
inhibitory concentration (MIC) was (11mm) were weakly active against the
determined using micro-broth dilution MRSA as shown in Table 3. The MIC and
methods (NCCLS, 2000). Concentrations of MBC values obtained showed that methanol
extracts (1-9 mgmL-1) dilutions were prepared extract of Acacia albida was most potent
using tubes containing 9 ml of double strength against the MRSA isolates (MIC, 3 mgmL-1
broth. The tubes were inoculated with the and MBC, 4 mgmL-1) (Table 3). The other
suspension of standardized inocula (0.5 plants extracts exhibited MIC 4 mgmL-1 and
McFarland standard) and incubated at 37°C MBC 5 mgmL-1 except Boscia senegalensis
for 24 h. MICs were recorded as the lowest which rather displayed high MIC, 5 mgmL-1
concentration of extract showing no visible and MBC, 6 mgmL-1.

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Table 1: Profile of the medicinal plants used

Botanical Name Family Local Name Part used Voucher Medicinal uses
number
Acacia albida Del. Leguminosae Gawo Stem bark 900334 Skin infections
Anchomanes Araceae Chakara Roots 900283 Cough and respiratory
difformis Engl. diseases.
Boscia senegalensis Capparidaceae Anza Roots 6921 Cancer, ulcer and
(PERS) Lam. swellings
Bridelia ferruginea Euphorbiaceae Kirni Stem bark 1750 Antibiotic, skin
Benth. infection, diuretic,
febrifuge and urethral
discharge.
Ficus ingens (Miq.) Moraceae Kawuri Stem bark 1504 Piles,diarrhea, laxative
Miq. and diuretic.
Indigofera arrecta Papilionoideae Ba-ba Aerial part 663 Infections, stomach pain,
Hochst snake bite and epilepsy.
Indigofera pulchraI Papilionoideae Bakin bunu Aerial part 409 Infected wound,malaria,
Willd dysentery and fever.
Moringa oleifera Moringacceae Zogale Leaf 571 Asthma, eye infection,
Lam. migraine headache,
febrifuge, abortifacient.
Mormodica Cucurbitaceae Garahuni Whole 3272 Laxative, antibiotic,
basalmina Linn plant antitumour, hypotensive,
purgative.
Pavetta crassipes K. Rubiaceae Gadau Leaf 3115 Respiratory diseases,
Schum. hypertension.
Phyllanthus amarus Euphorbiaceae Geron Whole 3073 Fever, diarrhea, kidney
Schumach & Thonn. tsuntsaye plant ailments, ringworm,
urinary tract infections,
hemorrhoids and
gonorrhea.
Vernonia Asteraceae Bagashi Aerial part 1784 Stomach or intestinal
blumeoides Hook. f. pain.

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Table 2: Phytochemical screening of extracts

Plants Phytochemicals
Alkaloids Flavonoids Saponins Tannins Cardiac Anthraquinone
Glycosides
Acacia albida Del. - + - + - +
Anchomanes - + + + - -
difformis Engl.
Boscia senegalensis + + + + + -
(PERS) Lam.
Bridelia ferruginea + + + + + -
Benth.
Ficus ingens (Miq.) + + + + + -
Miq.
Indigofera arrecta + + + + + -
Indigofera pulchra + + + + + -
Moringa oleifera + + + + - -
Lam.
Mormodica + + + + + -
basalmina L.
Pavetta crassipes K. + + - + + +
Schum.
Phyllanthus amarus + + + + + -
Schumach & Thonn.
Vernonia + + + + + -
blumeoides Hook. f.
Key: + = present - = absent

Table 3: Antibacterial activity, MIC and MBC of extracts

MRSA (n=25)
Plants Zone of inhibition (mm) MIC (mgmL-1) MBC (mgmL-1)
Acacia albida 30 3 4
Anchomanes difformis 13 4 5
Boscia senegalensis 19 5 6
Bridelia ferruginea 0 - -
Ficus ingens 0 - -
Indigofera errecta 0 - -
Indigofera pulchra 0 - -
Moringa oleifera* 10 4 5
Mormodica basalmina 15 4 5
Pavetta crassipes 22 4 5
Phyllanthus amarus 13 4 5
Vernonia blumeoides* 11 4 5

MIC: minimum inhibitory concentration,

MBC: minimum bactericidal concentration,
*: Plant sample extracted with ethanol

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DISCUSSION extracts are lower than the MBC, suggesting

The result of phytochemical screening that the plant extracts were bacteriostatic at
revealed the presence of flavonoids and lower concentration and bactericidal at higher
tannins in all extracts. Flavonoids and tannins concentration. Thus our findings support that
have been reported to posses antimicrobial of Abu-Shanab et al., (2006) where he
activity, the antimicrobial activity of evaluated the antibacterial activity of four
flavonoids is due to their ability to complex plant extracts used in Palestine folkloric
with extracellular and soluble protein and to medicine against MRSA. The inhibitory
complex with bacterial cell wall while that of activity found in this study was more
tannins may be related to their ability to pronounced than that reported by Akinyemi,
inactivate microbial adhesions, enzymes and et al., (2005) where he evaluated certain plant
cell envelop proteins (Cowan, 1999). The extracts used in South-Western Nigerian
results of antibacterial activity against 25 unorthodox medicine against MRSA. This
hospital isolates of MRSA have indicated that may probably be due to solvents and or
methanol extract of Acacia albida was found method of extraction used (Rios and Recio,
to be significantly active exhibiting the 2005). In addition, the greater potency against
highest potency with MIC of 3 mgmL-1 and MRSA was observed in methanol extracts due
MBC of 4mgmL-1. This activity may be to its ability to solubilize more antimicrobials
attributed to the rich tannins contents of bark from plants than ethanol and water (Eloff,
of the plant. Pavetta crassipes extract was 1998).Our investigation further revealed that
found to exhibit activity against the MRSA even though the leaves extract of Bridelia
with 22mm zone of inhibition. Similarly, ferruginea was reported to have significant
interesting activity was demonstrated against antibacterial activity (Talla, et al., 2002), the
the MRSA by Phyllantus amarus extract with methanol extract of the stem bark was found
zone of inhibition 13mm. Previously, the plant to be inactive against MRSA. The results of
has been reported to have promising our study revealed great therapeutic potentials
antibacterial and antifungal activity (Onocha, of these plants such as Acacia albida, Pavetta
et al., 2003; Kloucek, et al., 2005).This is an crassipes, Boscia senegalensis and
indicative that pharmacologically active Mormodica basalmina which might be used as
compounds are responsible for the recorded adjunct in the treatment of MRSA and
activity. The inhibitory activity exhibited by associated infections. Further identification of
Boscia senegalensis was 19mm but the MIC the active constituents is needed to exploit
and MBC were however found to be 5 mgmL- them in evaluating efficacy and safety in vivo
1
and 6 mgmL-1 respectively. In this study it against MRSA.
was observed that the MIC of the active plants

ACKNOWLEDGEMENTS Shehu Gallah of the Herbarium of Biological

To the authority of Ahmadu Bello University, Sciences Department, Ahmadu Bello
Zaria, for providing the facilities for University, Zaria; for identifying the plants.
conducting the research and Mallam Umar

REFERENCES
Abu-Shanab, B., Adwan, G., Jarrar, N., Abu-hijleh, A., Akinyemi, K.O., Oladipo, O., Okwara, C.E., Ibe, C. C.,
Adwan, K. (2006). Antibacterial activity of four plants Fasure, A.A. (2005). Screening of crude extracts of six
extracts used in Palestine in folk medicine against medicinal plants used in South-Western Nigerian
Methicillin-Resistant Staphylococcus aureus. Turk. J. unorthodox medicine for anti-methicillin resistant
Biol., (30), 195-198. Staphylococcus aureus activity. BMC. Comp. Altern.
Med., 5:6

6
Aliyu et al., Nig. Journ. Pharm. Sci., March, 2008, Vol. 7 No. 1, P. 1– 8

aureus in eight African hospitals and Malta. Clin.

Aqil, F., Ahmad, I., Owais, M. (2006). Evaluation of Microb. Infect. 9(2),153-156.
anti-methicillin resistant Staphylococcus aureus
(MRSA) activity and synergy of some bioactive plant Kim, K.J., Yu, H.H., Cha, J.D., Seo, S.J., Choi, N.Y.,
extracts. Biotech. J., 1(10), 1093-1102. You Y.O. (2005). Antibacterial activity of Curcuma
longa L. against Methicillin-resistance Staphylococcus
Burkill, H.M. (1995).The Useful Plants of West aureus. Phytother. Res. 19(7), 599-604.
Tropical Africa. Royal botanic garden Kew, 3,361-670.
Klevens, R.M. Edward, J.R., Tenover, F.C., McDonald,
Centre for Disease Control and Prevention, National L.C., Horan, T., Gaynes, R. (2006). Changes in the
Nosocomial Infections Surveillance (NNIS) System epidemiology of methicillin resistance Staphylococcus
report (2003). Am. J. Infect. Contr., 31, 481-498 aureus in intensive care units in US hospitals, 1992-
2003. Clin. Infect. Dis. 42, 389-391.
Centre for Disease Control and Prevention, National
Nosocomial Infections Surveillance (NNIS) System Kloucek, P., Polesny, Z., Svobodova, B., Vlkova, E.,
report (2004). Data summary from January 1992 Kokoska, L. (2005). Antibacterial screening of some
through June 2004. Am. J. Infect. Contr., 32, 470-485. Peruvian medicinal plants used in Callería District. J.
Ethnopharmacol. 99(2), 309-312.
Chambers, H.F. (1997). Methicillin Resistance in
Staphylococci: Molecular and Biochemical basis and Lennette, E.H. (1985). Manual of clinical
Clinical implications. Clin Microb Rev., 10(4),781-791. Microbiology. Fourth Edition. American Association of
Microbiology, Washington DC p.1149.
Chambers, H.F. (2003). Tracking the spread of
CMRSA. APUA Newsletter, 21(2): 1-5 Nascimento, G.G.F., Locatelli, J., Freitas, P.C., Silva,
G.L. (2000). Antibacterial activity of plant extracts and
Cowan, S.T., Steel, S. (1993). Manual for the phytochemicals on antibiotic resistant bacteria. Braz. J.
identification of Medical Bacteria. In Barrow GI, Microbiol. 31,247-256.
Feltham RKA (Ed.) Cambridge University Press. P. 32.
NCCLS, (2000). Methods for Dilution Antimicrobial
Cowan.M.M. (1999) Plant products as antimicrobial Susceptibility Tests for Bacteria That Grow
agents. Clin. Micr. Rev., 12(4), 564-582. Aerobically; Approved Standard Fifth Edition. NCCLS
Doerge, R.F., Wilson, C.O., Grivol, O. (1971). Document M7-A5, NCCLS: Wayne, PA, USA.
Textbook of Organic medicine and Pharmaceutical
Chemistry. 6th edition, Lippinncot Company, NCCLS, (1993). Performance Standards Antimicrobial
Philadelphia. Pp. 34-37. Disc Susceptibility Tests. Approved Standard Fifth
Edition. NCCLS Document M2-A5, Villanova, PA,
Eloff, J.N. (1998). Which extractant should be used for USA.
the screening and isolation of antimicrobials
components from plants? J. Ethnopharmacol., 60, 1-8 Nwaogu, L.A., Alis, C.S., Ibegbulem, C.O., Igwe, C.U.
(2007). Phytochemical and antimicrobial activity of
European Antimicrobial Research Surveillance System. ethanolic extract of Landolphia owariensis leaf. Afr. J.
EARSS annual report 2002 [Online] [cited 2004, Feb, Biotech. 6(7), 890-893.
24] Available from
http://www.earss.rivm.nl/PAGINA/DOC/rep2002/annu Onanuga, A., Oyi, A.R., Onaolapo, J.A. (2005).
al-report-2002.pdf Prevalence and susceptibility pattern of methicillin
resistant Staphylococcus aureus isolates among healthy
Iwu, M.M., Duncan, A.R., Okunji, C.O. (1999). New women in Zaria, Nigeria. Afr. J. Biotech. 4(11), 1321-
Antimicrobials of Plant Origin. In: Janick J (ed.) 1324.
Perspectives On new Crops and uses. ASHS Press,
Alexandria, V. A. pp. 457-462. Onocha, P.A., Opegbemi, A.O., Kadri, A.O., Ajayi,
K.M., Okorie, D.A. (2003). Antimicrobial evaluation of
Kesah, C., Ben-Redjeb, S., Odugbemi, T.O., Boye, Nigerian Euphorbiaceae plants 1: Phyllantus amarus
C.S.B., Dosso, M., Ndinya-Achola, J.O., Koulla-Shiro, and Phyllantus muellerantus leaf extracts. Nig. J. Nat.
S., Benbachir, M., Rahal, K., Borg, M. (2003). Prod. Med. 7, 9-12
Prevalence of methicillin resistant Staphylococcus

7
Aliyu et al., Nig. Journ. Pharm. Sci., March, 2008, Vol. 7 No. 1, P. 1– 8

Polombo, E.A., Semple, S.J. (2002). Antibacterial Antimicrobial activity of Bridelia ferruginea leaves
activity of Australian plants extracts against extracts. Fitoter. 73(4),343-345.
methicillin-resistant Staphylococcus aureus (MRSA)
and vancomycin-reisitant enterococci (VRE). J. Bas. Trease, G.E. and Evans, W.C. (1989). Pharmacognosy,
Microbio.l 42(6),444-448. 13th edition; ELBS Oxford University Press, London,
UK, Pp. 245-263.
Rios, J.L., Recio, M.C. (2005). Medicinal plants and
antimicrobial activity. J. Ethnopharmacol. 100, 80-81. Voravuthikunchai, S.P., Kitpipit, L. (2005). Activity of
medicinal plant extracts against hospital isolates of
Sofowora, A. (1993). Medicinal Plants and Traditional methicillin resistant Staphylococcus aureus. Clin.
Medicine in Africa. 2nd edition; Spectrum Books Ltd, Microbiol. Infect. 11(6), 510-512.
Ibadan, Nigeria. p. 289.
Zhang, R., Eggleston, K., Rotimi, V., Zeckhauser, R.J.
Talla, E., Djamen, D., Djouldé, D., Tatsadjeu, L., (2006). Antibiotic resistance as a global threat:
Tantoh, D., Mbafor, J.T., Fomum, Z.T. (2002). Evidence from China, Kuwait and the United States.
Globalization and Health 2(6), 1-14.