Abstract

To study the potential mechanisms underlying cholesterol metabolism regulation and the antioxidant of platycodin D derived from Platycodon grandiflorum A.DC (PD), the male Wistar rats treated with hyperlipidemic emulsion diet for 2 weeks were fed with PD (10, 20 and 30 mg/kg body weight/d) and simvastatin (25 mg/kg body weight/d), respectively by gavage for 28 days. Different doses of PD depressed the serum and hepatic cholesterol, triglyceride and low-density lipoprotein cholesterol concentration, thereby increasing the liver low-density lipoprotein cholesterol receptor (LDL-r) protein content by immunohistochemical analysis and decreasing liver 3-Hydroxy-3-methyl glutaryl-CoA reductase (HMG-CoA-r) mRNA levels of hyperlipidemic emulsion induced rats. Cytochrome P450 7A1 (CYP7A1) mRNA expression and fecal bile acid levels were significantly higher in the PD groups as compared to the groups that have only hyperlipidemic emulsion. Simultaneously, treatment with PD also improved the serum and hepatic homogenate metabolic antioxidant status of hyperlipidemic emulsion induced rats. These findings suggested that metabolism regulation of PD on hyperlipidemic rats was caused, in part, by regulation of synthesis, influx and efflux of hepatic intracellular cholesterol via the key points LDL-r, HMG-CoA-r and CYP7A1, which consequently changed the organismal oxidation state. The study revealed that PD may offer a therapeutic potential for the treatment of hyperlipidemic via regulation of cholesterol metabolism.

Key words: Platycodon grandiflorum, platycodin D cholesterol metabolism, antioxidation.