Apple polyphenols inhibit plasma CETP activity and reduce the ratio of non-HDL to HDL cholesterol.
Previous reports demonstrated that hypocholesterolemic activity of apple was associated with its pectin and fiber. This report was to investigate the effect of apple polyphenols (AP) on blood cholesterol level and gene expression of cholesterol-regulating enzymes in Golden Syrian hamsters maintained on a 0.1% cholesterol diet. It was found that dietary supplementation of 0.3 or 0.6% of AP did not affect plasma total cholesterol (TC), but it increased HDL cholesterol (HDL-C) and decreased non-HDL-C, thus leading to a lower ratio of non-HDL-C to HDL-C. Plasma total triacylglycerol (TG) level was also significantly reduced when hamsters were fed a diet supplemented with 0.6% AP. Western blot analysis did not find any effect of AP on sterol regulatory element-binding protein 2 (SREBP-2), LDL receptor (LDLR), 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), and cholesterol-7alpha-hydroxylase (CYP7A). Most interesting was that supplementation of AP had no effect on protein abundance of plasma cholesteryl ester transport protein (CETP), but it suppressed plasma CETP activity. A series of in vitro assays confirmed that AP inhibited CETP in a dose dependent manner. It was concluded that AP favorably improved distribution of cholesterol in lipoproteins, most likely, by its inhibition on CETP activity.
Lam
Cheuk Kai
CK
Food and Nutritional Sciences Programme, Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, China.
Zhang
Zesheng
Z
Yu
Hongjian
H
Tsang
Suk-Ying
SY
Huang
Yu
Y
Chen
Zhen Yu
ZY
D000818:Animals; D015153:Blotting, Western; D002784:Cholesterol / Q000097:blood*; D053480:Cholesterol Ester Transfer Proteins / Q000097:blood*; D008076:Cholesterol, HDL / Q000097:blood*; D006224:Cricetinae; D004435:Eating / Q000187:drug effects; D005243:Feces / Q000737:chemistry; D005419:Flavonoids / Q000494:pharmacology*; D006903:Hydroxymethylglutaryl CoA Reductases / Q000032:analysis; D008297:Male; D027845:Malus / Q000737:chemistry*; D008647:Mesocricetus; D009929:Organ Size / Q000187:drug effects; D010636:Phenols / Q000494:pharmacology*; D059808:Polyphenols; D011973:Receptors, LDL / Q000032:analysis; D051782:Sterol Regulatory Element Binding Protein 2 / Q000032:analysis; D015430:Weight Gain / Q000187:drug effects
D053480:Cholesterol Ester Transfer Proteins; D008076:Cholesterol, HDL; D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D011973:Receptors, LDL; D051782:Sterol Regulatory Element Binding Protein 2; D002784:Cholesterol; D006903:Hydroxymethylglutaryl CoA Reductases