Hypocholesterolemic effects of curcumin via up-regulation of cholesterol 7a-hydroxylase in rats fed a high fat diet

There is an increasing interest in curcumin (Curcuma longa L.) as a cardiovascular disease (CVD) protective agent via decreased blood total cholesterol and low-density lipoprotein-cholesterol (LDL-cholesterol) level. The aim of this study was to investigate further the potential mechanism in the hypocholesterolemic effect of curcumin by measuring cholesterol 7a-hydroxylase (CYP7A1), a rate limiting enzyme in the biosynthesis of bile acid from cholesterol, at the mRNA level. Male Sprague-Dawley rats were fed a 45% high fat diet or same diet supplemented with curcumin (0.1% wt/wt) for 8 weeks. The curcumin diet significantly decreased serum triglyceride (TG) by 27%, total cholesterol (TC) by 33.8%, and LDL-cholesterol by 56%, respectively as compared to control group. The curcumin-supplemented diet also significantly lowered the atherogenic index (AI) by 48% as compared to control group. Hepatic TG level was significantly reduced by 41% in rats fed with curcumin-supplemented diet in comparison with control group (P < 0.05). Conversely, the curcumin diet significantly increased fecal TG and TC. The curcumin diet up-regulated hepatic CYP7A1 mRNA level by 2.16-fold, compared to control group p (P < 0.05). These findings suggested that the increases in the CYP7A1 gene expression may partially account for the hypocholesterolemic effect of curcumin.