Influence of the methanolic extract from Abutilon indicum leaves in normal and streptozotocin-induced diabetic rats

The methanolic leaf extract of Abutilon Indicum (AI) was investigated for hypoglycemic effect in normal and streptozotocin-induced diabetic rats. The chemical screening of the extract showed that phenolic compounds and flavonoid contents were 1.04 +/- 0.01 mg/g and 59.92 +/- 3.88 mu g/g extract, respectively. A single oral administration of the extract at a dose of 500 mg/kg significantly decreased the blood glucose concentrations in both normal and diabetic rats after 2 h administration. Metformin was used as the reference drug and reduced the blood glucose only in diabetic rats. To clarify the involved mechanism, normal rats were orally administered with sucrose and maltose at a dose of 3 g/kg with or without AI extract. The postprandial elevation in the blood glucose concentrations at 30 min after the administration of sucrose with the extract was significantly suppressed when compared with the control group. No significant change in blood glucose concentrations was observed in maltose-loading rats. An in vitro study indicated that AI extract inhibited alpha-glucosidases, the disaccharide-digesting enzyme in the small intestine. The extract showed a potent sucrase inhibitory activity with IC50 of 2.45 +/- 0.13 mg/ml while the extract was less potent on the maltase inhibition. The results suggested that the extract from AI extract would be effective for lowering and suppressing elevation of blood glucose.