Effect of Pongamia Bark Extract on antihyperglycemic effect of glibenclamide for possible herb-drug interaction

Use of herbs or herbal medicines with prescription allopathic medicines may lead to beneficial or harmful herb-drug interaction, which needs a scientific substantiation. The present study was intended to determine the interaction between glibenclamide and methanolic extract of bark of Pongamia glabra Vent. (PBME), a herb with reported antidiabetic effect. The interaction was evaluated in normal and alloxan-induced diabetic rats using the parameters such as glucose tolerance test, acute and sub-acute levels of antidiabetic study and body weight estimations at various intervals. Glibenclamide was administered orally at two different doses of 300 μg/kg (low dose) and 600 μg/kg (high dose) and PBME was co-administered at the dose of 200 mg/kg. Individual treatments of above drugs were also carried out. Significant (P<0.001) hypoglycemic effect was observed with the combination therapy of glibenclamide and PBME compared to their individual treatments in the above studied parameters. The combination therapy showed more percentage increase in body weight than the individual treatments. The study indicates that the present herb-drug interaction was beneficial as PBME showed synergistic effect with glibenclamide. This could provide an opportunity to reduce the dose of glibenclamide to achieve an enhanced therapeutic effect with minimal side effects.