RESUMO
Diabetes mellitus is a major and current epidemic disease of the human race implicated with numerous clinical manifestations. A number of protein-rich seeds such as that of Citrullus lanatus (watermelon) are commonly used in traditional medicine with increasing acclaimed efficacy against diabetes mellitus. In this study the effects of petroleum ether and ethanol extracts of the seeds of Citrullus lanatus on blood glucose levels in alloxan-induced diabetes in mice have been investigated. Hyperglycemia was induced by the injection of 150 mg/kg (i.p.) of alloxan monohydrate freshly dissolved in physiological saline. Doses (150, 200 and 250 mg/kg) per os, of the extracts were separately administered to a group of five diabetic mice in the study. The activity was compared with reference standard glibenclamide (2 mg/kg, p.o.) and negative control of physiological saline. Treatment of alloxan-induced diabetic mice with the crude extracts of C. lanatus seeds brought down the raised blood glucose levels significantly (P < 0.05) in a dose-dependent manner. The ethanol extract was found to have more antidiabetic effect than the petroleum ether extract. Phytochemical screening of the seed extracts of Citrullus lanatus indicated the presence of steroids, alkaloids, flavonoids, terpenoids, and saponins in both the ethanol and petroleum ether extracts. In addition, anthraquinones, tannins and reducing sugar were detected in the ethanol extract.