Abstract

This study was carried out to investigate the hypoglycemic effects of ethanol extract and its chloroform and ethyl acetate fractions of Rhaphidophora glauca (Wall.) Schottleaves in normal and glucose induced hyperglycemic mice (in vivo). Area under curve (AUC) was also calculated during oral glucose tolerance test (OGTT). Ethanol extract and its fractions of R. glauca leaves at 400 and 800 mg/kg doses significantly (P < 0.05-0.001) reduced fasting glucose level in normal mice as compared to standard drug glibenclamide (5 mg/kg). Ethanol extract of R. glauca (EERG) at 800 mg/kg dose showed the highest hypoglycemic effect among the extract and fractions and it decreased 25.13% of the blood glucose level after 2 h of administration in normal mice, where glibenclamide decreased to 49.30%. In oral glucose tolerance test, at 400 and 800 mg/kg dose of extract and fractions significantly reduced blood glucose level (P < 0.05) at 30 min, but at 60 and 90 min, blood glucose level reduction is not all properly significant as compared to the control. At 120 min, both doses of extract and fractions significantly (P < 0.01) reduced blood glucose level. Whereas glibenclamide (5 mg/kg) significantly reduced glucose level at every hour after administration. EERG at 800 mg/kg dose showed the highest hypoglycemic effect among the extract and fractions and it decreased to 13.28% of blood glucose level after 2 h of administration in glucose induced mice, where glibenclamide decreased to 41.18%. AUC during OGTT of extract and fractions are at the range of 12.713 to 13.188 h.mmol/L., and 14.573 and 9.835 h.mmol/L for control and glibenclamide, respectively. These findings suggest that the plant may be a potential source for the development of new oral hypoglycemic agent.

Key words: Rhaphidophora glauca, hypoglycemic activity, area under curve (AUC), ethanol extract, fractions, glucose induced.