Protective effects of madecassoside, a triterpenoid from Centella asiatica, against oxidative stress in INS-1E cells

Progressive decline in beta cell function and reduction in the beta cell mass is important in type 2 diabetes. Here, we tested the hypothesis that madecassoside's previously demonstrated in vivo protective effects on the beta cell in experimental diabetes were exerted directly. We investigated the effects of madecassoside in protecting a beta cell line (INS-1E) against a variety of agents. INS-1E cells were treated with madecassoside in the presence of high glucose (HG), a cytokine mixture, hydrogen peroxide (H2O2), or streptozotocin (STZ). HG, the cytokine mixture, H2O2 and STZ each produced a significant decrease in cell viability; this was significantly reversed by madecassoside. Pre-treatment with madecassoside reduced the number of apoptotic cells induced by HG, the cytokine mixture, H2O2, and STZ, and concentration-dependently reduced ROS production. Madecassoside also significantly enhanced glucose-induced insulin secretion. The results suggest that madecassoside's in vivo effects are exerted directly on the beta cell.