Insulin Secretion and Glucose Uptake Enhancement by Mimosa pudica and Abutilon indicum: Potential Antidiabetic Therapy

Mimosa pudica (M) and Abutilon indicum (A) are used as an antidiabetic mixture at a ratio of 1:1 (MA11)in traditional Thai medicine. However, the mechanisms by which these plants exhibit antidiabetic effects have not been clearly elucidated. In this study, RINm5F insulinoma cells were treated with 6 mM streptozotocin (STZ) for 1 h to induce cellular damage and generate an in vitro model of diabetes. Extracts from M and A and mixtures of M and A extracts contain several phytochemicals, including flavonoids, tannins and saponins. All the extract samples at a concentration of 1,000 µg/mL exhibited antioxidant activity without cytotoxicity to RINm5F and L6 myotube cells. Pretreatment with M or A or with a mixture of the two prevented STZ-induced RINm5F cell death in a concentration-dependent manner. The greatest recovery effect was found in MA12, followed by MA11 and MA21. In addition, the M and A extracts and the mixtures of M and A extracts (100,000 mg/mL) exhibited insulin secretory activity in RINm5F cells that was similar to that of glibenclamide. Furthermore, all the plant extracts induced glucose uptake in L6 myotube cells. The induction of glucose uptake by M, A, and mixtures of M and A was derived from the upregulation of GLUT1 and GLUT4 synthesis in L6 myotube cells. These results indicate that M. pudica and A. indicum are potential sources of antidiabetic agents. In conclusion, the antidiabetic formula of M and A at a ratio of 2:1 (MA21) has the greatest potential for therapeutic use as an antidiabetic herbal mixture.