Antihyperglycemic activity of agarwood leaf extracts in STZ-induced diabetic rats and glucose uptake enhancement activity in rat adipocytes

Agarwood leaf extract was found to possess antipyretic, laxative and antimicrobial activities. A trial of one diabetic patient taking long term agarwood leaf tea was found to have blood glucose returned to normal. In this work, the effects of methanol, water and hexane crude extracts of agarwood leaf on hyperglycemia in streptozotocin-induced diabetic rats were investigated. Only methanol and water extracts at the dose of 1 g/kg body weight lowered the fasting blood glucose levels, 54 and 40%, respectively. The results were comparable to 4 U/kg body weight of insulin (73%). In in vitro experiment, the effect of the methanol and water extracts at the concentration of 10 g/mL enhanced glucose uptake activity on rat adipocytes by 172±10 and 176±21% of the control, respectively. The glucose uptake enhancement activity is comparable to 1.5 nM insulin (166±16%). The thin-layer chromatographic characteristics of all extracts were documented. The findings suggest that agarwood leaf is a promising potential antidiabetic agent.