Downregulation of hepatic lipoprotein assembly in rats by fermented products of Monascus pilosus.

OBJECTIVE

Hypercholesterolemia is a major risk factor for atherosclerosis. The fermented products of Monascus sp. have been known for their antihypercholesterolemic effect; however, the studies mostly have focused on the inhibition of cholesterol biosynthesis in liver. In this study, we examined whether fermented products of Monascus pilosus have regulatory effects on the hepatic lipoprotein assembly.

METHODS

Male Wistar rats were fed 1% cholesterol diet for 2 wk. After hypercholesterolemia was induced, the animals were maintained on this cholesterol diet supplemented with M. pilosus-fermented products grown in regular medium/garlic-containing medium or garlic powder for another 6 wk. The concentration of blood lipids and the expression of proteins involved in lipoprotein assembly and hepatic antioxidation were assayed.

RESULTS

Maintenance on a 1% cholesterol diet for 2 wk significantly (P < 0.05) raised animals' blood lipid levels and increased the expression of intestinal microsomal triacylglycerol transfer protein, hepatic apolipoprotein B-100, and acyl-coenzyme A:cholesterol acyltransferase. Supplementation of M. pilosus-fermented products or garlic powder significantly (P < 0.05) lowered animals' blood lipid levels and inhibited the expression of intestinal microsomal triacylglycerol transfer protein and hepatic apolipoprotein B-100. The 3-hydroxy-3-methylglutaryl-coenzyme A reductase was downregulated by the M. pilosus-fermented product grown in regular medium but not in garlic-containing medium. The expression of antioxidant enzymes was significantly upregulated by the M. pilosus-fermented product grown in garlic-containing medium.

CONCLUSION

Monascus sp.-fermented products exert the hypocholesterolemic effect by mechanisms other than the inhibition of cholesterol biosynthesis.