Evaluation of antioxidative and antidiabetic activity of bark of holarrhena pubescens wall

The objectives of the study are to screen out various phytochemicals and to evaluate the antioxidant and antidiabetic potential of the stem bark of Holarrhena pubescens Wall (Holarrhena antidysenterica).

The antioxidant activity was determined by the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity where ascorbic acid was taken as positive control. The antioxidant property was later exploited and the methanolic extract of plant was tested for antihyperglycemic activity in glucose overloaded hyperglycemic mice. The extract was tested for its hypoglycemic activity at two-dose levels, 250 and 500 mg/kg respectively where Glipizide 5 mg/kg was taken as standard reference drug. All results are presented as mean ± SD (Standard Deviation). Significant differences between experimental groups were determined by Student's t-test.

The methanolic and water extract showed strong antioxidant activity with inhibition of more than 90% DPPH free radicals at the concentration of 100μg/mL. The hypoglycemic activity of methanolic extract on glucose tolerance test were significant (p <0.05) for the effects of 500 mg/kg after 120 min of treatment and (p <0.01) for 250 mg/kg of extract after half hour of treatment compared to control.

The presence of flavonoides, phenolic compounds suggested that they may be partially responsible for antioxidant and antidiabetic activity.