OP alleviated the T2DM characteristics through the activation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/glycogen synthase kinase 3 beta (GSK3β) pathway, and enhanced the nuclear factor erythroid-2 (Nrf2) expression and promoted Nrf2-medicated heme oxygenase-1(HO-1) and superoxide dismutase 2 (SOD2) expression. This evidence concerns the gene HMOX1 and type 2 diabetes mellitus.