LAUSR

Abstract Rosemary extract (RE), a useful component isolated from Rosmarinus officinalis L., was recently reported to protect cells against the harmful effects of ROS. However, the underlying mechanisms of this action remained unknown. We investigated the defensive effect of RE on the oxidative stress injury resulted from high fat diet in hamsters and oleic acid (OA) in HepG2 cells respectively, and its underlying mechanisms. Treatment with RE alleviated liver steatosis and reduced plasma and liver content of TG and TC, as well as plasma content of AST and ALT. RE apparently increased the activity of SOD, GSH-Px, CAT and decreased MDA content. RE notably increased CuZn-SOD, Mn-SOD, CAT, GSH-Px, GCLC, GCLM and Nrf2 mRNA and protein expression level. Nrf2 shRNA knockdown in HepG2 cells increased OA-induced ROS generation, and effectively altered OA-induced cytotoxicity, suggesting that Nrf2 is a crucial mediator against high-fat induced oxidative damage.