In vitro and in vivo antidiabetic effect of Andrographis lineata Wall. Ex.Nees and Andrographis serphyllifolia Wt.Ic leaf extracts

Andrographis lineata and Andrographis serphyllifolia are endemic potential medicinal plants of South India. The leaves of both the herbs have been used as ancient folklore medicine for curing diabetes, snakebite, inflammation and cancer. The present investigation deals with the study of in vitro and in vivo antidiabetic effect of the ethanolic leaf extract of A. lineata (EtALL) and ethanolic leaf extract of A. serphyllifolia (EtASL). Qualitative analysis of phytochemicals revealed the presence of alkaloids, tannins, terpenoids, steroids, flavanoids and polyphenol compounds, absence of saponins and steroids in both the extracts. The α-glucosidase inhibition results of EtALL (IC 50 value 10.12 µg/ml) and EtASL (IC 50 value 11.39 µg/ml) exhibited stronger inhibitory activity for α-glucosidase which was comparable with Acarbose. The 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay of the EtALL and EtASL extracts in 3T3-L1cell line confirmed that there was no toxicity effect for both the extracts from 6.5 to 50 µg/ml concentrations. The glucose uptake rate in 3T3-L1 cells revealed the fact that both the extracts showed increase in glucose uptake rate in dose dependent manner comparable to insulin. Further these extracts were evaluated in the in vivo model to prove the traditional claim of usage pertaining to antidiabetic property. The acute toxicity studies showed that there was no death or lethal effect observed in toxicity study. The acute treatment of fasting blood sugar and oral glucose tolerance test of EtALL and EtASL extract (400 mg/kg b.w.) treated normoglycemic rats showed hypoglycemic effect. When the streptozotocin induced diabetic rats was administered with EtALL and EtASL 400 mg/kg b.w. in chronic model (28 days) there was a significant reduction in plasma glucose, plasma insulin level, total cholesterol, low density lipoprotein (LDL)-C triglyceride, glucose-6phosphatase and fructose -1, 6- bisphosphatase levels. Glycogen content (liver and muscle), high density lipoprotein (HDL) cholesterol, hexokinase, was significantly increased compared with the diabetic control rats in both the extracts treated rats. The above findings showed the significant antidiabetic potential of the extracts in ameliorating the diabetic condition in the diabetic treated rats. Further studies are in progress to identify the active principle’s possible for the antidiabetic effect in EtALL and EtASL extracts.