PTPN1 and type 2 diabetes mellitus: Overall, a variety of mechanisms account for the hypoglycemic effects of apigenin as follows: inhibiting the expression of PTP1B, a negative modulator of the insulin and leptin signaling pathway; increasing the anti-oxidant enzymes and reducing ROS formation, DNA damage, and carbonylation of protein which are increased by T2DM; and preventing beta cell apoptosis in the pancreas.