Antidiabetic Effects of Some Tropical Fruit Extracts in Fructose Induced Insulin Resistant Wistar Rats

Aim: Fruit extracts of Apple (Malus domestica), coconut (Cocos nucifera) and cucumber (Cucumis sativus) were tested for their antidiabetic potential in rats with fructose-induced insulin resistance for 28 days. Study Design: In-vivo antidiabetic study using fructose-induced insulin resistant rats. Place and Duration of Study: Department of Biochemistry, Lagos State University, Ojo, Lagos, Nigeria, between March and May 2014. Methodology: Wistar rats were randomized into 5 groups comprising 5 animals each. Group A (control) was fed on standard rat chow and distilled water ad libitum while Groups B-E were fed standard rat chow and 10% w/v fructose. Groups C-E were also administered 500 mg/kg body weight of apple, coconut and cucumber extracts for 28 days. At the end of the experiment, all animals were sacrificed and the serum glucose, lipid profile and electrolytes were determined. Results: The fructose-fed rats had significantly decreased weight and increased blood glucose concentration (P < 0.05), when compared to the control rats. The fructose-fed rats also witnessed significant increase (P < 0.05) in total cholesterol and low density lipoprotein cholesterol (LDLC) concentration as well as significant decrease (P < 0.05) in the high density lipoprotein (HDLC) and serum electrolytes concentration compared to control. Administration of the aqueous extracts of apple, coconut and cucumber to the fructose-fed rats significantly increase (P < 0.05) their body weights, HDLC and serum electrolytes’ concentration in the rats while significantly reducing (P < 0.05) blood glucose, total cholesterol and LDLC. Conclusions: Aqueous extracts of apple, coconut and cucumber displayed antidiabetic effect, but apple exhibited the most potent effect as it ameliorates most of the derangements observed in insulin-resistant rats.