Policosanol has no antioxidant activity in human low-density lipoprotein but increases excretion of bile acids in hamsters.
Policosanol is a group of long chain primary alcohols and has been shown to reduce blood cholesterol levels and to inhibit the oxidation of low-density lipoprotein (LDL). The present study examined (i) the effect of policosanol supplementation in the diet on the fecal excretion of neutral and acidic sterols in hamsters and (ii) the antioxidant activity of policosanol in human LDL. Golden Syrian hamsters were divided into four groups (n = 12/each) fed one of the four diets containing 0 (control), 0.38, 0.75, and 1.50 g kg(-1) policosanol for 6 weeks. It was found that hamsters given 0.38-1.5 g kg(-1) diets had a serum total cholesterol level lowered by 15-25% and had a high-density lipoprotein cholesterol elevated by 7-16.8%. It was found that policosanol increased the excretion of acidic sterols by 25-73%. Contrary to that in previous reports, policosanol had no apparent anti-LDL oxidation activity when 1-tetracosanol, 1-hexacosanol, and 1-octacosanol were incubated in human LDL. Policosanol also possessed no scavenging activity on the free radical2,2-diphenyl-1-picrylhydrazyl. These data provide evidence that in addition to the effect of HMG-CoA reductase, the cholesterol-lowering activity of policosanol is partially mediated by its inhibition on the absorption of bile acids, but these data disprove the claim that policosanol is an antioxidant.
Ng
Chi Ho
CH
Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, China.
Leung
Ka Yiu
KY
Huang
Yu
Y
Chen
Zhen Yu
ZY
D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage*; D001647:Bile Acids and Salts / Q000032:analysis / Q000378:metabolism*; D002784:Cholesterol / Q000032:analysis / Q000097:blood; D006224:Cricetinae; D004032:Diet; D005233:Fatty Alcohols / Q000008:administration & dosage*; D005243:Feces / Q000737:chemistry; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects*; D008055:Lipids / Q000097:blood; D008077:Lipoproteins, LDL / Q000097:blood*; D008297:Male; D008647:Mesocricetus
D000975:Antioxidants; D001647:Bile Acids and Salts; D005233:Fatty Alcohols; D008055:Lipids; D008077:Lipoproteins, LDL; C080710:policosanol; D002784:Cholesterol