Hypoglycemic and anti-hyperglycemic study of Gynura procumbens leaf extracts

Objective:To study the antidiabetic activity of Gynura procumbens(G.procumbens)used in the traditional management of diabetes in Southern Asia.Methods:G.procumbens leaves were extracted sequentially with graded percentage of ethanol in water(95%,75%,50%,25%and 0%),and the extracts were tested for antidiabetic activity using acute(7 h),subcutaneous glucose tolerance test and sub-chronic(14 d)test in non-diabetic and streptozotocin-induced diabetic rats.The extracts were further subjected to phytochemical studies.Results:In acute dose(1 g/kg),the extracts significantly lowered fasting blood glucose(FBG)in streptozotocin-induced diabetic rats(P<0.05).However,the FBG-lowering effect of the 25%extract compared to the other extracts,was rapid(47%after 2 h)and the highest:53%,53%and 60%in the 3rd,5th,and 7th h,respectively(P<0.05),comparable only to the effect of metformin.Furthermore,the extracts suppressed peak FBG in subcutaneous glucose tolerance test,but only the 0%and 25%extracts,and metformin sustained the decrease until the 90th min(P<0.05).Moreover,in the 14 days study,the 25%extract exerted the highest FBG-lowering effect,namely 49.38%and 65.43%on days 7 and 14,respectively(P<0.05),similar to the effect of metformin(46.26%and 65.42%).Total flavanoid and phenolic contents in the extracts were found to decrease with increase in polarity of extraction solvents.The composition of reference compounds(chlorogenic acid,rutin,astragalin and kaempferol-3-O-nrtinoside)followed a similar trend.Conclusions:G.procumbens contains antidiabetic principles,most extracted in 25%ethanol.Interaction among active components appears to determine the antidiabetic efficacy,achieved likely by a metformin-like mechanism.