Identification of bioactive heterocyclic compounds from mulberry and their protective effect against streptozotocin-induced apoptosis in INS-1 cells

A phytochemical investigation of the MeOH extracts from mulberries (the fruit of Morus alba L.) led to the identification of six heterocyclic compounds (1-6). These compounds were screened to detect whether they protected pancreatic INS-1 cells from streptozotocin (STZ)-induced cytotoxicity. Compound 3 was the most effective at preventing STZ-induced cytotoxicity and the production of reactive oxygen species (ROS) in INS-1 cells. In addition, compound 3 effectively prevented apoptosis induced by STZ in INS-1 cells. Compound 3 also prevented STZ-mediated cleavage of caspase-8, caspase-3 and poly (ADP-ribose) polymerase and increased the expression of B-cell lymphoma-2 (Bcl-2), an anti-apoptotic Bcl-2 family protein. In conclusion, the results of the present study indicate that compound 3 extracted from the fruit of M. alba was highly effective in preventing type 1 diabetes mellitus and may be a novel treatment option.