Abstract

Earlier we have reported the antidiabetic activity of fresh juice of rhizomes of Zingiber officinale and its correlation with 5-HT receptor antagonism. Since 6-gingerol the marker compound of Z. officinale is reported to posses 5-HT antgonistic activity, the present investigation was undertaken to find out the concentration of 6-gingerol present in methanolic extract and ethyl acetate extract of Z. officinale. We also evaluated these extracts for antidiabetic activity in streptozotocin-induced type 2 diabetic rats. Streptozotocin-induced type 2 diabetic rats showed a significant increase in fasting glucose levels that was associated with increase in insulin levels. Treatment with methanolic extract and ethyl acetate extract of Z. officinale produced a significant decrease in fasting glucose and insulin levels in type 2 diabetic rats. In oral glucose tolerance test, treatment with methanolic extract and ethyl acetate extract of Z. officinale was found to significantly decrease AUCglucose and AUClnsulin, values in type 2 diabetic rats. Treatment with methanolic extract produced greater reduction in elevated levels of glucose and AUCglucose compared to ethyl acetate extract. Treatment with methanolic extract and ethyl acetate extract of Z. officinale also produced decrease in serum cholesterol, triglyceride, LDL-cholesterol and VLDL-cholesterol levels in type 2 diabetc rats. The concentration of &ginger01 was found to be greater in methaolic extract (3.08%) and lower in ethyl acetate extract (1.64%). In conclusion our data suggest methanolic extract of Z. officinale to have better antidiabetic activity in type 2 diabetic rats as compared to ethyl acetate extract of Z. officinale. The extent of activity appears to be dependent on the concentration of 6-ginger01 present in the extracts.