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Plasma Cholesterol-lowering Activity of Selected Nutraceuticals and Associated Mechanisms.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Plasma Cholesterol-lowering Activity of Selected Nutraceuticals and Associated Mechanisms./
作者:	Zhao, Yimin.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2018,
面頁冊數:	126 p.
附註:	Source: Dissertations Abstracts International, Volume: 80-06, Section: B.
Contained By:	Dissertations Abstracts International80-06B.
標題:	Food Science. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=11012185
ISBN:	9780438658875

Plasma Cholesterol-lowering Activity of Selected Nutraceuticals and Associated Mechanisms.
Zhao, Yimin.

Plasma Cholesterol-lowering Activity of Selected Nutraceuticals and Associated Mechanisms. - Ann Arbor : ProQuest Dissertations & Theses, 2018 - 126 p.

Source: Dissertations Abstracts International, Volume: 80-06, Section: B.

Thesis (Ph.D.)--The Chinese University of Hong Kong (Hong Kong), 2018.

This item must not be sold to any third party vendors.

Hypercholesterolemia is the leading cause of atherosclerosis and cardiovascular disease. Nutraceuticals for the prevention and treatment of hypercholesterolemia have gained increasing interest in recent years. The present study was therefore to examine the plasma-cholesterol effects of selected nutraceuticals including short-chain fatty acids (SCFAs), Balsamic and Chinese Shanxi vinegars, and piperine in hamsters and the associated mechanisms. SCFAs are the end products of gut fermentation of dietary fiber. It is reported that SCFAs can reduce blood cholesterol while the underlying mechanisms remained largely unknown. The first part of the present study aimed to compare the structure-specific cholesterol-lowering property of individual SCFAs and the underlying mechanisms. Five groups of male hamsters were fed either a control high-cholesterol (HCD) or one of the four experimental HCDs containing 0.5 mol of acetate (Ac), propionate (Pr), butyrate (Bu), or valerate (Va) per kilogram of the diet for 6 week, respectly. It is observed that Ac, Pr, and Bu significantly reduced plasma total cholesterol (TC) by 24, 18, and 17%, respectively. All four SCFAs could decrease non-HDL-C (non-high-density lipoprotein cholesterol) and the non-HDL-C/HDL-C (high-density lipoprotein cholesterol) ratio. Ac, Pr, or Bu also substantially stimulated fecal excretion of bile acids and upregulated the mRNA expressions of sterol regulatory element-binding protein 2 (SREBP2), low-density lipoprotein receptor (LDLR), and cholesterol 7 alpha-hydroxylase (CYP7A1) in the liver. Therefore, SCFAs with 2-4 carbons are more effective in decrease plasma TC than Va, via enhancing fecal excretion of bile acids and promoting the hepatic uptake of cholesterol from the blood. Both Balsamic vinegar of Modena (BV) and Chinese Shanxi vinegar (SV) are traditional food condiments. Recent researches also suggests that both vinegars may possess a variety of health benefits. The second part of the thesis aimed to study the effects of BV and SV on cholesterol metabolism in hamsters. Five groups of hamsters were fed the non-cholesterol diet (NCD), HCD, HCD+BV, and HCD+SV. BV and SV were diluted to obtain the same concentrations of acetic acid at 20 mg/mL to adjust for acetic acid intake. The hamsters were orally gavaged with BV and SV at a dose of 8mL/kg body weight/day. After 9 weeks, it was observed that BV and SV markedly lowered plasma concentrations of TC and non-HDL-C compared with HCD. In addition, BV and SV also significantly reduced liver cholesterol contents and promoted fecal excretion of neutral sterols and bile acids. Real-time PCR analysis demonstrated that BV and SV significantly upregulated the mRNA expression of CYP7A1 in the liver. In addition, BV administration significantly upregulated the mRNA expression of LDLR while SV downregulated the expression of microsomal triacylglycerol transfer protein (MTP) in the small intestine. Administration of BV or SV did not affect the fecal excretion of acetic acid or total short-chain fatty acids compared with HCD. Therefore, BV and SV were effective in reducing plasma TC and non-HDL-C concentrations in hamsters. Piperine is the major pungent ingredient in black and white peppers. Piperine has been reported to be hypocholesterolemic. The third part of the present study aimed to elucidate the interaction between piperine and key regulatory factors involved in cholesterol absorption and metabolism in hamsters. Thirty-two hamsters were assigned into four groups receiving one of four diets namely a NCD, a HCD, and the two HCD diets containing 0.03% (PL) and 0.06% (PH) piperine, respectively, for 6 weeks. Results showed that PL and PH supplementation significantly reduced plasma TC by 16-17%, and non-HDL-C by 24-25%, respectively. This was accompanied by 84-109% increase in fecal excretion of neutral sterols with downregulation on gene expression of intestinal NPC1L, ACAT2, and MTP in a dose-dependent manner. Therefore, it was concluded that plasma TC-lowering activity of piperine was mediated by reducing the intestinal cholesterol absorption via inhibition on gene expression of intestinal Niemann-Pick C1-Like 1 (NPC1L1), acetyl-CoA acetyltransferase 2 (ACAT2), and MTP.

ISBN: 9780438658875Subjects--Topical Terms:

890841
Food Science.

Plasma Cholesterol-lowering Activity of Selected Nutraceuticals and Associated Mechanisms.
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