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SCIENTIFIC RESEARCH
Publications J. Sci. Res. 5 (1), 161-170 (2013) www.banglajol.info/index.php/JSR

Hypoglycemic and Hypolipidemic Effects of Cucumber, White Pumpkin and

Ridge Gourd in Alloxan Induced Diabetic Rats

R. Sharmin1, M. R. I. Khan2, Most. A. Akhter2*, A. Alim3, M. A. Islam2,

A. S. M. Anisuzzaman2, and M. Ahmed2
1
Department of Pharmacy, Jessore Science and Technology University, Jessore
2
Department of Pharmacy, Rajshahi University, Rajshahi-6505, Bangladesh
3
Square Pharmaceuticals Ltd., Kaliakoir, Gazipur-1750, Dhaka, Bangladesh

Received 2 April 2012, accepted in final revised form 20 December 2012

Abstract
Ethanolic extracts of some fruits of Cucurbitaceae family such as Cucumis sativus
(cucumber), Lagenaria siceraria (white pumpkin), Luffa acutangula (ridge gourd),
Benincasa hispida (ash gourd), Citrullus lanatus (sweet melon) and Cucarbita maxima
(pumpkin) have been studied for their hypoglycemic effects on alloxan induced diabetic rats
(AIDRs). Screening results suggested that among the tested fruits the hypoglycemic potency
follows: cucumber > white pumpkin > ridge gourd. These three fruit-extracts were further
investigated for their hypoglycemic, hypolipidemic and glycogenesis effects. Cucumber,
white pumpkin and ridge gourd extracts reduced blood glucose level by 67, 65 and 51%,
respectively at 12 hours after single intraperitoneal injection; while reduced the low density
lipoprotein (LDL) level to 13, 28 and 86%, respectively in AIDRs. The maximum reduction
87% was observed by cucumber extract. Cucumber, white pumpkin and ridge gourd
extracts reduced total cholesterol level to 29, 15 and 38%, respectively comparing with the
diabetic control group. Here the maximum reduction of 85% was observed by white
pumpkin extract. Cucumber, white pumpkin and ridge gourd also reduced triglyceride
levels to 72, 68 and 80%, respectively. Maximum reduction of 32% was observed by white
pumpkin. Significant improvement of glycogenesis was also observed by ridge gourd
extracts in AIDRs.
Keywords: Blood glucose; Hypoglycemic; Hypolipidemic; Diabetic rats.
© 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.
doi: http://dx.doi.org/10.3329/jsr.v5i1.10252 J. Sci. Res. 5 (1), 161-170 (2013)

1. Introduction

Diabetes is a growing health problem in the world today. Almost 1.3% of the population
suffers from this disease throughout the world [1] and number of diabetics is increasing by
6% per year [2].

*
Corresponding author: afia2441139@yahoo.com, aashuva@yahoo.com
162 Hypoglycemic and Hypolipidemic

Diabetes mellitus is a metabolic disorder characterized by chronic hyperglycemia

resulting from defects in insulin secretion, insulin action, or both. It is associated with
reduced life expectancy, significant morbidity due to specific diabetes related micro
vascular complications (retinopathy, nephropathy and neuropathy), increased risk of
macrovascular complications (ischemic heart disease, stroke and peripheral vascular
disease) and diminished quality of life [3]. The major mode of controlling diabetes can be
achieved by diet, exercise, and insulin replacement therapy and/or by different oral
hypoglycemic drugs. In modern medical system, managing diabetes without side effects is
still a challenge.
Unfortunately, after the introduction of sulfonylurea and metformin about 50 years
back no major lead has been obtained in this direction of finding a proper drug for
diabetes. Plant materials, which are being used as traditional medicine for the treatment of
diabetes, are considered one of the good sources for a new drug or a lead to make a new
drug. Plant extract or different folk plant preparations are being prescribed by the
traditional practitioners and also accepted by the users for diabetes in many countries
especially in third world countries. Now-a days more than 400 plants are being used in
different forms for hypoglycemic effects all the claims practitioners or users are neither
baseless nor absolutely. Therefore, a proper scientific evaluation, a screening of plant by
pharmacological tests followed by chemical investigations is necessary [4]. Now a days,
scientists and researchers are very much interested on research of natural plant products
all over the world and a large amount of substantiation have shown the immense potential
of medicinal plants used traditionally [5]. In the last few years there has been an
exponential growth in the field of herbal medicine and these drugs are gaining popularity
both in developing and developed countries because of their natural origin and less side
effects [6]. Cucurbits (Cucurbitaceae) are among the most important plant families
supplying humans with edible products and useful fibers. There are several plants of
Cucurbitaceae family, which are established for their antidiabetic properties such as
Momordica charantia [7], and Coccinia indica [8]. Our preliminary screening results
suggested that Cucumis sativus (cucumber), Luffa acutangula (ridge gourd) and
Lagenaria siceraria (white pumpkin) had more potent antidiabetic effects. Therefore, in
this work, we tried to investigate the antidiabetic and hypolipidemic effects of these three
fruits extracts of Cucurbitaceae family in chemically induced diabetic rats model.
Cucumber (Cucumis sativus) originated in India but soon cultivated in different parts
of the world. In Mexico, cucumber is one of the edible plants with hypoglycemic activity.
Antihyperglycemic effect of this plant was studied in healthy rabbits, which significantly
decreased the area under the glucose tolerance curve and the hyperglycemic peak [9].
Ridge gourd (Luffa acutangula) is believed to have originated in India, but has now
spread pantropically to all areas with a high rainfall. In southern and eastern Asia it is a
widely cultivated vegetable. Ridge gourd is a demulcent and diuretic and seeds are emetic
and purgative [10]. The analgesic and hypoglycemic activities of ridge gourd was
evaluated in Swiss Webster mice where methanol extracts of ridge gourd showed
significant hypoglycemic activities when administered 15 min after glucose load using a
modified oral glucose tolerance test [11]. However, hypolipidemic and hepatoprotective
 R. Sharmin et al. J. Sci. Res. 5 (1), 161-170 (2013) 163

activities of cucumber (Cucumis sativus) and ridge gourd (Luffa acutangula) have not
been investigated so far.
White pumpkin (Lagenaria siceraria) is indigenous to Africa and that it reached
temperate and tropical areas in Asia and the Americas. It is a fruit vegetable used
throughout Bangladesh and India. Petroleum ether fraction of white pumpkin is reported
to possess antioxidant activity and hypolipidemic activity [12]. However there is a lacking
of enough evidence about the hypoglycemic activity of white pumpkin and its
hepatoprotective activities have not yet been investigated.

2. Materials and Methods

2.1. Plant materials

The fresh fruits of cucumber, white pumpkin, ridge gourd, ash gourd, sweet melon and
pumpkin were collected from the local market and authenticated by botanist Dr. A. H. M.
Mahbubur Rahman (Department of Botany, University of Rajshahi). They were cut into
small pieces, dried completely under the mild sun and ground with an electric grinder into
coarse powder. The powder was used for cold extraction.

2.2. Preparation of crude extracts

The coarse powders from different fruits were soaked in 95% ethanol for 7 days and were
kept at room temperature with occasional shaking and stirring. When the solvent became
concentrated, the liquid alcohol contents were filtered through cotton and then through
filter paper (Whatman filter paper no. 1). The ethanolic solution was allowed to evaporate
using rotary evaporator. Thus the highly concentrated ethanol extracts were obtained
which were further dried completely under mild sun and by freeze-drying. The dried
extracts were then preserved in the refrigerator for the experimental use.

2.3. Drugs and chemicals

Compounds were purchased from commercial sources as follows: Alloxan monohydrate;

Loba Chemiie, Mumbai, India. Total cholesterol (TC) and triglyceride (TG) kits;
Boehringer Mannheim, GmbH, Germany. Serum LDL diagnostic kits; Crescent
Diagnostics, Jeddah. Glycogen test diagnostic kit was o-toluidine reagent. The active
drug, metformin hydrochloride was the generous gift from Square Pharmaceuticals Ltd.
Pabna Bangladesh.

2.4. Induction of diabetes

Long-Evans female rats weighing about 110 –120 g were purchased from Animal House
of International Centre for Diarrheal Disease Research, Bangladesh (ICDDR, B). Prior to
the commencement of experiment, the rats were acclimatized in a well-ventilated animal
o
house at 25 C for a period of one week with adequate food and water ad libitum. For the
164 Hypoglycemic and Hypolipidemic

development of diabetic model, rats were grouped into six groups. Each group contains
three rats. After overnight fasting, a freshly prepared solution of alloxan monohydrate
(120 mg/kg body weight in normal saline) was administered intraperitoneally into group
II-VI. Group I kept as normal control group that did not receive the chemical. After 48
hours their blood glucose content was measured by glucometer (Clever Check, Germany)
according to the manufacturer’s protocol. Rats with blood glucose levels above 11.1
mM/L were selected for the study [13]. Their base line blood glucose level was also
measured just prior to the administration of alloxan.

2.5. Treatment of the animal

Group I and II served as non-diabetic and diabetic control group, respectively. Group III
stands for metformin control group in which metformin was administered as a single
intraperitoneal dose of 150mg/ kg body weight. Group IV, V and VI received cucumber,
white pumpkin and ridge gourd extracts, respectively as a single intraperitoneal dose of
200 mg/kg body weight. The blood samples were analyzed for blood glucose content at 0,
4, 8, and 12 hours, respectively.

2.6. Determination of serum total cholesterol (TC), serum triglyceride (TG) and serum
low density lipoprotein (LDL) levels

After completion of 12 hours experimental period rats were sacrificed and approximately
3-5 ml of blood samples were collected directly from heart by syringes. The collected
blood samples were centrifuged at 4000 rpm for 10 minutes and the resulting supernatant
was obtained as serum. Serum TC, TG and LDL concentrations were analyzed by UV
spectrophotometric method (Shimadzu UV-1200, Tokyo, Japan) using wet reagent
diagnostic kits according to the manufacturer’s protocol.

2.7. Estimation of glycogen content in liver

The liver tissues collected from sacrificed rats were analyzed for glycogen content by UV
spectrophotometric method using o-toluidine reagent diagnostic kits as we have reported
previously [14]. Briefly, this test utilizes the o-toluidine–glucose-coupling reaction for the
estimation of glycogen after trichloroacetic acid (TCA) extraction, precipitation by
alcohol and hydrolysis.

2.8. Statistical analysis

Data were expressed as mean ± standard error of mean (SEM). Statistical comparisons
were performed by one-way analysis of variance (ANOVA), or students paired or
unpaired t-test where appropriate. Results are considered to be significant when p values
 R. Sharmin et al. J. Sci. Res. 5 (1), 161-170 (2013) 165

were less than 0.05 (p<0.05). Statistical calculations and the graphs were prepared using
Graph Pad Prism version 5.00 for Windows (Graph Pad Software, San Diego, CA, USA).

3. Results

3.1. Effect of cucumber, white pumpkin, and ridge gourd extracts on fasting blood
glucose (FBG) level in alloxan induced diabetic rats (AIDRs)

After single intraperitoneal injection of cucumber, white pumpkin, and ridge gourd
extracts (200 mg/kg body weight), their fasting blood glucose (FBG) levels were
measured at 0, 4, 8, and 12 hrs, respectively. The cucumber extracts reduced FBG level to
81.02, 58.65 and 32.61% at 4, 8 and 12 hrs, respectively. Whereas, white pumpkin
reduced FBG level to 85.12, 58.82 and 34.60%; ridge gourd 85.73, 67.75 and 48.89% and
metformin HCl to 69.20, 44.95 and 25.44% at 4, 8 and 12 hrs, respectively. In each case
the effects were significantly different (P< 0.05) at 8 and 12 hrs from the diabetic control
group and maximum reduction of FBG level was achieved at 12 hr by 67.38, 65.39, 51.10
and 69.20% for cucumber, white pumpkin, ridge gourd and metformin HCl, respectively.
The results are shown in Fig. 1.

Fig. 1. Effect of cucumber, white pumpkin, and ridge gourd on FBG levels in AIDRs. # indicates
significant changes (increase) of blood glucose level compared with normal control group. *
indicates significant changes (decrease) of FBG level in diabetic rats after treatment compared with
zero hr treatment group. The results are expressed as means ± SEM.

3.2. Effect of cucumber, white pumpkin and ridge gourd on total cholesterol (TC),
triglyceride (TG) and low-density lipoprotein (LDL) levels in AIDRs

After induction of diabetes, the TC, TG and LDL levels were increased significantly in
AIDRs. Cucumber, white pumpkin, ridge gourd and metformin HCl decreased the
166 Hypoglycemic and Hypolipidemic

elevated serum TC levels to 28.83, 14.91, 38.38 and 14.50%, respectively. The maximum
reduction of 85.08% was observed by white pumpkin extract. The elevated serum TG
levels were reduced to 70.64, 68.24, 79.64 and 60.48%, by cucumber, white pumpkin,
ridge gourd and metformin HCl, respectively. The maximum reduction of 31.76% was
observed by white pumpkin. On the other hand, serum LDL level was reduced to 13.07,
27.67, 85.66 and 16.05% when treated with cucumber, white pumpkin, ridge gourd and
metformin HCl, respectively. A maximum reduction of 86.92% was observed by
cucumber ethanol extract. The summarized results are shown in the Figs. 2, 3 and 4 for
TC, TG, and LDL levels, respectively.

Fig. 2. Effect of cucumber, white pumpkin and ridge gourd on TC levels in AIDRs. # indicates
significant difference from normal control after diabetes induction. * indicates significant change
from diabetic control group after treatment with different extracts.

Fig. 3. Effect of cucumber, white pumpkin and ridge gourd on TG levels in AIDRs. After treatment
with the extracts of cucumber, white pumpkin and ridge gourd, there was a tendency of the decrease
of elevated TG levels. However, the reduction was not significantly different.
 R. Sharmin et al. J. Sci. Res. 5 (1), 161-170 (2013) 167

Fig. 4. Effect of cucumber, white pumpkin and ridge gourd on LDL levels in AIDRs. # indicates
significant difference from normal control after diabetes induction. * indicates significant change
from diabetic control group after treatment with different extracts.

3.3. Effect of cucumber, white pumpkin, and ridge gourd on glycogen synthesis in
AIDRs

In this study it was found that the level of glycogen content in liver was reduced to
75.32% in diabetic rats as compared to the normal control group. Treatment of diabetic
rats with metformin standard, cucumber, and ridge gourd extracts improved the glycogen
levels to 196.10%, 107.79% and 149.35%, respectively as shown in the Fig. 5 and Table
1.

Fig. 5. Effect of cucumber, white pumpkin, and ridge gourd on glycogen synthesis in AIDRs. ‘ *’
indicates significant improvement of glycogen levels after treatment compared with diabetic control
group.
168 Hypoglycemic and Hypolipidemic

Table 1. Effect of cucumber, white pumpkin, and ridge gourd on glycogen synthesis in AIDRs. ‘*’
indicates significant improvement of glycogen levels after treatment compared with diabetic control
group.

Treatment 12 hr

Normal control 7.7 ± 0.01

Diabetic control 5.8 ± 0.01

D+metformin 15.1 ± 0.04*

D+cucumber 8.3 ± 0.02

D+white pumpkin 5.6 ± 0.03

D+ridge gourd 11.5 ± 0.05*

Values are expressed as mean ± SEM of 3 experiments.

4. Discussion

Numerous oral hypoglycemic drugs exist alongside insulin; still there is no promising
therapy to cure diabetes [15]. In recent years, many traditional medicinal plants were
tested for their antidiabetic potential in the experimental animals [16]. Although some of
these plants have great reputation in the indigenous system of medicine for their
antidiabetic activities, many remain to be scientifically established.
In the light of the literature of the Cucurbitaceae family, we made an attempt to study
the effect of cucumber (Cucumis sativus), white pumpkin (Lagenaria siceraria) and ridge
gourd (Luffa acutangula) ethanolic extracts in AIDRs to evaluate their hypoglycemic,
hypolipidemic and glycogenesis effect.
In this work we have shown that cucumber, white pumpkin and ridge gourd has
significantly decreased the elevated blood glucose levels in AIDRs (Fig. 1). The possible
mechanism by which these fruits extracts bring about their antidiabetic action may be by
potentiating the insulin effect of plasma by stimulating insulin release from the remnant
pancreatic β-cells or its release from the bound form [17]. Beside this, it might involve an
extra-pancreatic action in these alloxan-diabetic rats, which might include the stimulation
of peripheral glucose utilization or enhancing glycolytic and glycogenic processes with
concomitant decrease in glycogenolysis and gluconeogenesis [18]. The antihyperglycemic
activity of cucumber, white pumpkin and ridge gourd may also be due to the presence of
hypoglycemic saponins, tannins, triterpines, alkaloids, flavonoids etc [19].
Hypercholesterolemia and hypertriglyceridemia have been reported to occur in
diabetic rats [20-22]. Our previous work also reported hypertriglyceridemia and
hyperlipidemia in AIDRs [14]. The ethanol extracts from cucumber, white pumpkin and
ridge gourd significantly decreased serum cholesterol level in AIDRs (Fig. 2). Again
cucumber and white pumpkin significantly decreased serum LDL level (Fig. 4). The
 R. Sharmin et al. J. Sci. Res. 5 (1), 161-170 (2013) 169

mechanism of hypocholesterolemic action of cucumber, white pumpkin and ridge gourd

and LDL lowering action of these extracts are not known; it could be mediated through
the control of tissue metabolism and improved insulin secretion and action.
In the present study, we have also showed that the fruits extracts restored the
depressed hepatic glycogen levels (Fig. 5 and Table 1). Our results showed that
supplementation of diabetic rats with ethanol extracts of cucumber and ridge gourd
resulted in significant elevation in hepatic glycogen content. Decreased activities of
enzymes like glucose-6-phosphate and hexokinase are involved in glucose homeostasis in
liver and kidney resulting in depletion of liver and muscle glycogen content [23].
Treatment with these fruits extract might increase the activity of the said enzymes to the
control level indicating an overall increase in glucose influx. The exact mechanism of
action needs further investigation.

5. Conclusions

From the current study, it is concluded that the ethanol extracts of Cucurbitaceae family
fruits, cucumber, white pumpkin and ridge gourd has significant antihyperglycemic
effects in AIDRs. They also have the capacity to reduce the elevated lipid profiles in
AIDRs. Ridge gourd has also significant effects to restore the depressed hepatic glycogen
levels in AIDRs. Therefore, we believe that these fruits extracts can be useful, at least as
an adjunct, in the therapy of diabetes, a condition in which hyperglycemia and
hyperlipidemia coexist quite often. However, further study is necessary for the screening
of chemical compounds and the structure elucidation of the respective antidiabetic leads
as well as their exact mechanism.

Acknowledgements

We thank Pharmacy Department of Rajshahi University for providing necessary facilities

to carry out this research work. The present work was supported by the National Science
and Information and Communication Technology (NSICT), Dhaka, Bangladesh for
financial assistance to the first author and the authors would like to extend their gratitude
to the Director, Animal Research Centre, ICDDR,B for providing necessary facilities.

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