Insulin sensitizing property of Indigofera mysorensis extract

Indigofera mysorens is a shrub used for its antidiabetic activity in rural India. Here, we elucidate the antidiabetic potential of Indigofera mysorensis extract. Ethanolic extract of the whole shrub of Indigofera (EEI) at 300 mg/kg for 10 days, produced a 63% reduction in plasma glucose, 41% reduction in plasma triglyceride and 77% reduction in plasma insulin levels in insulin resistant db/db mice, which is better than insulin sensitizer, troglitazone (400 mg/kg). EEI unlike sulphonylureas failed to show any acute hypoglycemic effect in normoglycemic Swiss albino mice (SAM). Even in a chronic study (10 days) in SAM, EEI (300 mg/kg) like insulin sensitizers showed no effect on plasma glucose, but an 81% reduction in plasma insulin levels. When challenged with 3 gm/kg sucrose, SAM treated with EEI (300 mg/kg, 7 days) failed to show any effect on the absorption of sugar, whereas standard drug, acarbose (10 mg/kg) showed 52% reduction in the area under the plasma glucose curve. EEI failed to show any significant transactivation of PPARγ, a proposed target of synthetic insulin sensitizers. Taken together, our data indicate that the antidiabetic effect of the ethanolic extract of Indigofera is due to its insulin sensitizing property and is clearly different from that of sulfonylurea or acarbose.