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Ethnobotanical Leaflets 12: 1172-75. 2008. Anti-hyperglycaemic and Insulin Release Effects of Coccinia grandis
(L.) Voigt Leaves in A.
Doss and R. Dhanabalan PG Department of Microbiology Corresponding author: dossandro@gmail.com Issued
ABSTRACT Coccinia grandis (L.) Voigt (Cucurbitaceae), occurs
throughout the world and has intensive popular use in the treatment of
infections. The main aim of the present work was to investigate the antidiabetic effects of aqueous extracts of leaves of C. grandis obtained
by Decoction method. Graded doses of the aqueous extract were administered to
normal and experimental diabetic rats for 10 days. Significant (p <
0.05) reduction in fasting blood glucose levels were observed in the normal
as well as in the treated diabetic animals. Serum insulin levels were not
stimulated in the animals treated with the extract. The changes in body
weight, serum lipid profiles, liver glycogen levels were assessed in the
extract treated diabetic rats and compared with diabetic control and normal
animals. Key words: Antidiabetic activity, alloxan
monohydrate, Gliben clamide,
Coccinia grandis. INTRODUCTION Diabetes mellitus (DM) is a serious
health problem with high rates of incidence and mortality. DM is
characterized by elevated plasma glucose concentrations resulting from
insufficient insulin, insulin resistance or both leading to metabolic
abnormalities in carbohydrates, lipids and proteins (Hernandez-galicia et
al., 2002). According to the World Health Organization, more than 70% of
the world’s population must use traditional medicine to satisfy their
principal health needs (Farnsworth et
al., 1985). A great number of medicinal plants used in the control of the
DM have been reported (Baily & Day 1989; Marles & Farnsworth, 1994). However these plants
represent alternatives to developing new oral hypoglycemic agents,
appropriate ethnobotanical information is scarce, obscure
and ambiguous. Coccinia grandis (L.) Voigt. (Family: Cucurbitaceae) is a climbing perennial herb distributed
almost all over the world. The leaves of the plant possess antidiabetic, anti-inflammatory, antipyretic, analgesic, antispasmodic,
antimicrobial, cathartic and expectorant activities (Asolkar
et al, 1992; Nadkami and Nadkami,
1992).The leaves contain Triterpenoids, alkaloids
and tannins (Rastogi. and Mehrota,
1990). The objective of the present work is to
make an analysis of the ethnobotanical information
on Coccinia grandis used in South Indian region for
diabetes mellitus control. MATERIAL Plant material
and decoction preparation The leaves of C. grandis were collected in December 2007 from About 150 g of dried powdered
leaves were boiled in 1 liter of water for 5 min, allowing the decoction to
stand for 30 min and filtered through Whatman no.1
filter paper which yielded a decoction with a 15% higher concentration than
that of produced by the method described by Teixeira
et al., (1990). Test animals The test animals used in the study
were procured from Karpagam Medical and Research
Foundation. Six Albino rats of wistar strain weighing 150 - 200 g bred in Animal Tissue
Culture Lab, Karpagam Arts and Induction of
Experimental Diabetes and Treatment Alloxan
monohydrate solution of 10 mg/ml was prepared in ice-cold citrate buffer 0.1
M, pH 4.5 and was administered to the rats within 5 min at a dose of 50 mg/kg
body weight intraperitonially. After 48 h of alloxan monohydrate administration, rats with moderate
diabetes having glycosuria and hyperglycemia were
taken for the experiment. Rats weighing 150 – 160 g, fasted
over night were used for induction of diabetes. Rats were divided into two
sets; diabetic and non-diabetic. Group I received normal diet and served as
normal control. Group II consists of alloxan-induced
rats receiving normal diet and serving as diabetic control. Group Blood samples were collected
through the tail vein just prior to and on days 10 after drug administration.
The blood glucose, urea, cholesterol, serum glutamate oxygenate transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT)
were determined for all the samples. Statistics The data were analyzed using
one-way ANOVA followed by Dunnett's test. The level
of significance was set at 0.05. RESULTS The extracts of C. grandis produced
significant changes in the alloxan-induced diabetic
rats (Table 1). The aqueous extracts of C.
grandis reduced the glucose levels
considerably. Treatment of the diabetic rats with Gliben
clamide (10 mg/kg) also reduced blood glucose
level. The prolonged treatment of C. grandis extracts
on alloxan-induced diabetes rats produced
consistent reduction in the blood glucose levels. The aqueous extract also
reduced urea, protein and cholesterol during the 10 days treatment period
(Tables 1 and 2). It is possible that the drug may be
acting by potentiating the pancreatic secreation or increasing the glucose uptake.
Hypercholesterolemia, hypertriglyceridemia and hyperurea have been reported to occur in alloxan diabetic rats (Resmi et al., 2001; Joy and Kuttan, 1999). Increase in glycogen in liver can be
brought about by an increase in glycogenesis and/or
decrease a glycogenolysis. Therefore, the C. grandis extract
could have stimulated glycogenesis and/or inhibited
glycogenolysis in diabetic rat liver. The plant
extracts treated animals showed non-toxicity of the extract, which indicates
that unlike insulin and other common hypoglycemic agents, overdose of the
drug may not result in hypoglycemia. The increase in total protein (Table 2)
may be due to changes in circulating amino acids levels, hepatic amino acids
uptake, and muscle output of amino acid concentrations (Felig
et al., 1977). The non-protein
nitrogen compound urea is found to be increased when compared to plant
extract treated rats. The level of SGPT and SGOT increased remarkably in the C. grandis extract-treated rats (Nagappa et al.,
2003). Our results support Ghosh et al., (2004) who reported that transaminase activity is increased in serum of diabetics.
In diabetic animals, the changes in level of serum enzymes are directly related
to changes in the metabolism (Felig et al., 1977). C. grandis leaf extract showed
significant anti-diabetic effect in diabetic rats after oral administration.
Thus, the claim made by the Indian systems of medicine regarding the use of
leaf extract of this plant in the treatment of diabetes is validated. Present
efforts are directed to isolate the active constituents and elucidation of
mechanism of action. ACKNOWLEDGEMENTS The authors express their sincere
gratitude to the management of RVS College of Arts and Science, REFERENCE 1. Asolkar LV, Kakkar KK, Chakre
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Drug in alloxan-diabetic rats. Indian Drugs. 38(6): 319-322. Table 1. Glucose and cholesterol content of serum of control
and experimental rat groups.
Table 2. The Concentrations of urea, total protein, SGOT and
SGPT in serum of control and experimental groups.
Values are taken as mean of
five individual’s experiments and expressed as Mean ± S.D. ***p< 0.001, **p< 0.01
and *p< 0.05. NS = Not Significant. Group I & II -
Group Group IV - Diabetic treated with Plant drug Group V -
Plant drug |