Abstract
The main objective of the current study was to investigate the in vitro and in vivo antidiabetic activity of methanol extracts Carthamus oxyacantha leaves and corollas. In vitro antidiabetic assays such as inhibition of a-amylase enzyme, non-enzymatic glycosylation of hemoglobin and glucose uptake in yeast cells were carried out. The results of a-amylase inhibition assay revealed that the IC50 of methanol extracts of leaf and corolla were almost same (58.5 and 57.1 mu g/ml, respectively) when compared with positive control acarbose (45.3 mu g/ml). Glycosylation of hemoglobin was inhibited and the methanol extract of corolla showed an IC50 value of 61.7 mu g/ml, while methanol extract of the leaf showed 93.9 mu g/ml when compared to the positive control, a-tocopherol (35.4 mu g/ml). On the other hand, the percent glucose uptake in yeast cells caused by methanol extracts of leaf and corolla was distinctly greater when compared to that of metformin. In vivo antidiabetic study revealed that the two methanol extracts at a dose of 200 mg/kg reduced the fasting plasma glucose level (94.6 +/- 4.4 and 102.1 +/- 5.5 mg/dl, respectively) when compared to that of glibenclamide (79.4 +/- 3.4 mg/dl, p<0.001). The results from this study indicated that Carthamus oxyacantha leaf and corolla methanol extracts exhibited considerable in vitro and in vivo antidiabetic activities, which would make Carthamus oxyacantha a potential antidiabetic agent.