Ka Ying Ma

The Chinese University of Hong Kong, Hong Kong, Hong Kong

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Publications (28)83.2 Total impact

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    ABSTRACT: Cranberry is an excellent source of dietary antioxidants. The present study investigated the effect of cranberry anthocyanin (CrA) extract on the lifespan of fruit flies with focus on its interaction with aging-related genes including superoxide dismutase (SOD), catalase (CAT), methuselah (MTH), insulin receptor (InR), target of rapamycin (TOR), and phosphoenolpyruvate carboxykinase (PEPCK). Results showed that diet containing 20mg/mL CrA could significantly prolong the mean lifespan of fruit flies by 10% compared with the control diet. This was accompanied by up-regulation of SOD1 and down-regulation of MTH, InR, TOR and PEPCK. The stress resistance test demonstrated that CrA could reduce the mortality rate induced by H2O2 but not by paraquat. It was therefore concluded that the lifespan-prolonging activity of CrA was most likely mediated by modulating the genes of SOD1, MTH, InR, TOR and PEPCK. Copyright © 2015. Published by Elsevier Inc.
    Experimental gerontology 07/2015; 69. DOI:10.1016/j.exger.2015.06.021 · 3.53 Impact Factor
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    ABSTRACT: Cholesterol analogs have been used to treat hypercholesterolemia. The present study was to examine the effect of dihydrocholesterol (DC) on plasma total cholesterol (TC) compared with that of β-sitosterol (SI) in hamsters fed a high cholesterol diet. Forty-five male hamsters were randomly divided into 6 groups, fed either a non-cholesterol diet (NCD) or one of five high-cholesterol diets without addition of DC and SI (HCD) or with addition of 0.2% DC (DA), 0.3% DC (DB), 0.2% SI (SA), and 0.3% SI (SB), respectively, for 6 weeks. Results showed that DC added into diet at a dose of 0.2% could reduce plasma TC by 21%, comparable to that of SI (19%). At a higher dose of 0.3%, DC reduced plasma TC by 15%, less effective than SI (32%). Both DC and SI could increase the excretion of fecal sterols, however, DC was more effective in increasing the excretion of neutral sterols but it was less effective in increasing the excretion of acidic sterols compared with SI. Results on the incorporation of sterols in micellar solutions clearly demonstrated both DC and SI could displace the cholesterol from micelles with the former being more effective than the latter. DC was equally effective in reducing plasma cholesterol as SI at a low dose. Plasma TC-lowering activity of DC was mediated by inhibiting the cholesterol absorption and increasing the fecal sterol excretion. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
    Atherosclerosis 06/2015; 242(1):77-86. DOI:10.1016/j.atherosclerosis.2015.06.046 · 3.97 Impact Factor
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    ABSTRACT: The present study investigated the underlying mechanism by which citrus polymethoxylated flavones (PMF) reduced plasma triacylglycerols (TG) in hamsters. Four groups of male hamsters were given a non-cholesterol diet (NCD), a high cholesterol diet (HCD), a high cholesterol diet with supplementation of 0.5% PMF (L-PMF), and a high cholesterol diet with supplementation of 1.0% PMF (H-PMF), respectively, for 8 weeks. Results showed PMF could lower plasma TG by 32-46% but it had no effect on plasma cholesterol in hamsters. This was accompanied by down-regulation of mRNA of liver sterol regulatory element binding protein-1c (SREBP1c), fatty acid synthase (FAS), and peroxisome proliferator activated receptor alpha (PPARα) while up-regulation of liver lipoprotein lipase (LPL). In addition, dietary PMF increased cholesterol by 5-15% and total lipids by 34-43% in the liver. PMF supplementation also reduced the body weight gain and the relative weights of white adipose tissue pads by 23-39%, possibly by decreasing the gene expression of FAS and LPL in epididymal fat pad. It was concluded that plasma TG-lowering activity of dietary PMF was mediated by modulating genes involved in lipid metabolism in hamsters.Practical applications: Hyperlipidemia is one of the risk factors for coronary heart diseases. The present study found that polymethoxylated flavones (PMF) were effective in reducing plasma triacylglycerols and adipose tissue weight. PMF may be developed as a nutraceutical to prevent hyperlipidemia and obesity.
    European Journal of Lipid Science and Technology 04/2015; DOI:10.1002/ejlt.201500060 · 2.03 Impact Factor
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    ABSTRACT: Sesame seed is rich in sesamin. The present study was to (i) investigate the plasma cholesterol-lowering activity of dietary sesamin; and (ii) examine the interaction of dietary sesamin with the gene expression of sterol transporters, enzymes, receptors and proteins involved in cholesterol metabolism. Thirty hamsters were divided into three groups fed the control diet (CON) or one of two experimental diets containing 0.2% (SL) and 0.5% (SH) sesamin, respectively, for 6 weeks. Plasma total cholesterol (TC) in hamsters given the CON, SL and SH diets was 6.62±0.40, 5.32±0.40 and 5.00±0.44 mmol/L, respectively, indicating dietary sesamin could reduce plasma TC in a dose-dependent manner. Similarly, the excretion of total fecal neutral sterols was dose-dependently increased with the amounts of sesamin in diets (CON: 2.65±0.57; SL: 4.30±0.65 and SH: 5.84±1.27 µmol/day). Addition of sesamin into diets was associated with down-regulation of mRNA of intestinal Niemann-Pick C1 like 1 protein (NPC1L1), acyl-CoA: cholesterol acyltransferase 2 (ACAT2), microsomal triacylglycerol transport protein (MTP), ATP-binding cassette transporters sub-family G member 5 and 8 (ABCG 5 and 8). Results also showed that dietary sesamin could up-regulate hepatic cholesterol- 7α-hydroxylase (CYP7A1) while it down-regulated hepatic 3-hydroxy -3-methyl-glutaryl-CoA (HMG-CoA) reductase and liver X receptor alpha (LXRα). It was concluded that the cholesterol-lowering activity of sesamin was mediated by promoting the fecal excretion of sterols and modulating the genes involved in cholesterol absorption and metabolism.
    Journal of Agricultural and Food Chemistry 03/2015; 63(11). DOI:10.1021/jf5063606 · 3.11 Impact Factor
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    ABSTRACT: The present study (i) compared plasma cholesterol-raising activity of free cholesterol (FC) with that of cholesteryl palmitate (CP) and (ii) examined plasma cholesterol-reducing activity of β-sitosterol in FC-induced and CP-induced hypercholesterolemia. Male hamsters were divided into five groups and fed one of the five diets containing no cholesterol (NC), 2.6 mmol cholesterol (C), 2.6 mmol cholesterol plus 2.6 mmol β-sitosterol (C+S), 2.6 mmol cholesteryl palmitate (CP), and 2.6 mmol CP plus 2.6 mmol β-sitosterol (CP+S), respectively, for 8 weeks. Hamsters fed diet C had plasma TC of 317.5 mg/dl whereas hamsters fed diet CP has plasma TC of 281.3 mg/dl. β-Sitosterol reduced plasma TC by 17.4% and 11.6%, respectively, in FC-induced and CP-induced hypercholesterolemia (not significant). It was concluded that plasma cholesterol-raising activity of dietary cholesterol was a function of its chemical forms in diet, and β-sitosterol could similarly suppress the hypercholesterolemia induced by both dietary FC and CP.
    Food Chemistry 02/2015; 169:277–282. DOI:10.1016/j.foodchem.2014.07.123 · 3.39 Impact Factor
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    ABSTRACT: β-Sitosterol (SI) is hypocholesterolemic. The present study investigated whether the blockage of its hydroxyl group would abolish its cholesterol-lowering activity. The blockage was made by methylating and ethylating the hydroxyl group on C3 position, leading to formation of β-sitosteryl 3β-methoxy (SM) and β-sitosteryl 3β-ethoxy (SE) derivatives. Male hamsters were divided into five groups (n = 8 each) and fed the non-cholesterol diet (NCD), high cholesterol diet containing 5 mmol of cholesterol (HCD), or one of the three high cholesterol experimental diets with addition of 5 mmol of SI (HCD + SI), 5 mmol of SM (HCD + SM) and 5 mmol of SE (HCD + SE), respectively, for 8 weeks. Results showed that SI could significantly reduce plasma total cholesterol (TC) by 17% (P < 0.05), while SM and SE had no effect on plasma TC. It was concluded that the hydroxyl group was essential for SI to render its cholesterol-lowering activity and its blockage abolished this ability.
    Journal of Functional Foods 01/2015; 12. DOI:10.1016/j.jff.2014.11.019 · 4.48 Impact Factor
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    ABSTRACT: Cholesterol analogs can be used to treat hypercholesterolemia. The present study was to test the effects of cholesteryl 3β-ethoxy (CE) and cholesteryl 3β-methoxy (CM) on plasma total cholesterol (TC) compared with that of β-sitosterol (SI) in hamsters fed a high cholesterol diet. CM and CE are the methoxy and ethoxyl analogs of cholesterol while SI is an analog of cholesterol having an additional ethyl group on the side chain. Results showed that SI at a dose of 0.1% could effectively reduce plasma TC by 18%. The analysis of sterols in plasma and liver did not detect the presence of SI, proving it was poorly absorbed in the intestine. In contrast, both CE and CM had no effect on plasma TC. However, CE and CM were found to accumulate in both plasma and liver, indicating they could be well absorbed in the intestine. It was therefore concluded that analogs having the different side chains possessed plasma TC-lowering activity, while analogs or derivatives on the hydroxyl group had no hypocholesterolemic activity.
    12/2014; 6(2). DOI:10.1039/C4FO01044B
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    ABSTRACT: Plant sterol esters are the popular cholesterol-lowering dietary supplements. In order to understand the role of fatty acid moieties in the cholesterol-lowering activity of plant sterol esters, the present study was to: (i) compare the cholesterol-lowering activity of sterol esters of sunflower oil (SSF) with that of sterol esters of canola oil (SCO); and (ii) to systematically investigate the effect of SSF and SCO on the gene expression of sterol transporters, enzymes, receptors and proteins involved in cholesterol metabolism in hamsters fed a high cholesterol diet. GC analysis showed that SSF and SCO had similar sterol profile but they had different fatty acid moieties. Results showed both SSF and SCO could equally reduce plasma cholesterol in a dose-dependent manner. Both SSF and SCO could inhibit the cholesterol absorption and enhance the excretion of bile acids. In the similar ways, dietary SSF and SCO could up-regulate hepatic cholesterol-7α-hydroxylase (CYP7A1) and down-regulate intestinal sterol transporter Niemann-Pick C1-like 1 (NPC1L1), acyl coenzyme A: cholesterol acyltransferase 2 (ACAT2) and hepatic 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoA reductase). It was concluded that the fatty acid moieties had little effect on the cholesterol-lowering activity of SSF and SCO.Practical applications: Plant sterols are effective in reducing plasma cholesterol. Commercially, plant sterol esters of sunflower oil and plant sterol esters of canola oil are mostly used for this purpose. The present study found that SSF and SCO were equally effective in reducing plasma cholesterol in a dose-dependent manner regardless the significant difference in their fatty acid compositions.Fatty acid moieties have little effect on cholesterol-lowering potency of plant sterol esters.
    European Journal of Lipid Science and Technology 12/2014; 117(5). DOI:10.1002/ejlt.201400444 · 2.03 Impact Factor
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    ABSTRACT: The present study investigated the cholesterol-lowering activity of gingerols- and shogaols-riched ginger extract (GSE). Thirty hamsters were divided into three groups and fed the control diet or one of the two experimental diets containing 0.5% and 1.0% GSE. Plasma total cholesterol, liver cholesterol, and aorta atherosclerotic plaque were dose-dependently decreased with the increasing amounts of GSE added into diets. The fecal sterol analysis showed dietary GSE increased the excretion of both neutral and acidic sterols in a dose-dependent manner. GSE down-regulated the mRNA levels of intestinal Niemann-Pick C1 like 1 protein (NPC1L1), acyl CoA: cholesterol acyltransferase 2 (ACAT2), microsomal triacylglycerol transport protein (MTP), and ATP binding cassette transporter 5 (ABCG5), while it up-regulated hepatic cholesterol-7α-hydroxylase (CYP7A1). It was concluded that beneficial modification of lipoprotein profile by dietary GSE was mediated by enhancing excretion of fecal cholesterol and bile acids, via up-regulation of hepatic CYP7A1 and down-regulation of mRNA of intestinal NPC1L1, ACAT2 and MTP.
    Journal of Agricultural and Food Chemistry 10/2014; 62(43). DOI:10.1021/jf5043344 · 3.11 Impact Factor
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    ABSTRACT: Capsaicinoids exist in chili peppers while capsinoids are present in sweet pepper. The present study investigated the effects of capsaicinoids and capsinoids on plasma lipids, relaxation of aorta, atherosclerotic plaque development and fecal sterol excretion in hamsters. Five groups of male hamsters were fed the control diet or one of the four experimental diets containing 1.3 mmol capsaicinoids (NL), 2.6 mmol capsaicinoids (NH), 1.3 mmol capsinoids (OL) and 2.6 mmol capsinoids (OH), respectively. Results showed capsaicinoids but not capsinoids could decrease plasma total cholesterol (TC), reduce the formation atherosclerotic plaque and relax the aortic artery. This was accompanied by 28-175% increase in fecal excretion of acidic sterols in hamsters fed the diets containing capsaicinoids. Similarly, capsaicinoids but not capsinoids could decrease the pad weights of epididymal and prerenal adipose tissues. It was concluded that capsaicinoids but not capsinoids could favorably modulate plasma lipids and possess the beneficial vascular activity.
    Journal of Agricultural and Food Chemistry 07/2014; 62(33). DOI:10.1021/jf502888h · 3.11 Impact Factor
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    ABSTRACT: Interest in relationship between diet and ageing is growing. Research has shown that dietary calorie restriction and some antioxidants extend lifespan in various ageing models. On the one hand, oxygen is essential to aerobic organisms because it is a final electron acceptor in mitochondria. On the other hand, oxygen is harmful because it can continuously generate reactive oxygen species (ROS), which are believed to be the factors causing ageing of an organism. To remove these ROS in cells, aerobic organisms possess an antioxidant defense system which consists of a series of enzymes, namely, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR). In addition, dietary antioxidants including ascorbic acid, vitamin A, vitamin C, α -tocopherol, and plant flavonoids are also able to scavenge ROS in cells and therefore theoretically can extend the lifespan of organisms. In this connection, various antioxidants including tea catechins, theaflavins, apple polyphenols, black rice anthocyanins, and blueberry polyphenols have been shown to be capable of extending the lifespan of fruit flies. The purpose of this review is to brief the literature on modern biological theories of ageing and role of dietary antioxidants in ageing as well as underlying mechanisms by which antioxidants can prolong the lifespan with focus on fruit flies as an model.
    04/2014; 2014:831841. DOI:10.1155/2014/831841
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    ABSTRACT: This study was to examine the effect of free cholesterol (C) and individual cholesteryl ester (CE) species, namely cholesteryl palmitate (CP), cholesteryl stearate (CS), cholesteryl oleate (CO) and cholesteryl linoleate (CL), on plasma total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), non-HDL-C and triacylglycerols (TG) in hamsters. Results showed that addition of dietary CE species into diet at 0.1% differently raised plasma TC concentrations with CO elevating plasma TC to 331 mg/dl while CS raising plasma TC only to 220 mg/dl. It was found that CS was a poor while CO was a good substrate of pancreatic cholesterol esterase. The fecal analysis showed CS-fed hamsters had the highest fecal cholesterol concentration while RT-PCR analysis found CS feeding was associated with down-regulations of intestinal Niemann-Pick C1 Like 1 (NPC1L1) and acyl-CoA: cholesterol acyltransferase 2 (ACAT2) as well as microsomal triacylglycerol transport protein (MTP). It was therefore concluded that plasma cholesterol-raising activity of CE species was partially governed by their hydrolysis rates in the intestine, and the relative low raising activity associated with CS was mediated by down-regulation of intestinal NPC1L1, ACAT2 and MTP.
    Journal of Agricultural and Food Chemistry 10/2013; 61(46). DOI:10.1021/jf4039293 · 3.11 Impact Factor
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    ABSTRACT: The present study presents the antioxidant activity of sesamin in canola oil compared with that of butylated hydroxytoluene (BHT) by monitoring the oxygen consumption and the decrease in linoleic acid and α-linolenic acid. The oxidation of canola oil was conducted at 35, 60, 90, 120 and 180 °C with addition of 50–400 ppm sesamin. Results from the oxygen consumption test showed that sesamin dose-dependently inhibited the oxidation of canola oil at concentrations of 50–200 ppm at temperatures of 60–180 °C, however, sesamin lost its antioxidant activity at a low temperature of 35 °C. The fatty acid analysis also demonstrated that sesamin at 50, 100 and 200 ppm dose-dependently prevented the oxidation of linoleic acid and α-linolenic acid in canola oil. Both the oxygen consumption and the fatty acid analysis demonstrated sesamin was less effective than BHT as an antioxidant at temperatures of 60–180 °C. It was therefore concluded that sesamin could prevent the lipid oxidation of frying fats and oil, however, its antioxidant activity was not as potent as that of BHT.
    Journal of Oil & Fat Industries 04/2013; 90(4). DOI:10.1007/s11746-012-2198-4 · 1.62 Impact Factor
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    ABSTRACT: The present study investigated the anti-ageing activity of sesamin and its effect on gene expression of superoxide dismutase (SOD), catalase (CAT), methuselah (Mth) and Rpn11 in Drosophila melanogaster. Results demonstrated that 0.2 % sesamin in diet prolonged the mean lifespan of OR wild fruit flies by 12 %, accompanied by up-regulation of SOD1, SOD2, CAT and Rpn11. Sesamin at 0.2 % in diet also attenuated paraquat-induced neurodegeneration with up-regulation of SOD1, SOD2 and Rpn11 in OR wild fruit flies. Supplementation of 0.2 % sesamin in diet increased the survival time of OR wild type flies and Alzheimer flies Aβ42 33769 when they were challenged with paraquat. Furthermore, sesamin-induced increase in the activity and expression of antioxidant enzymes also suggests that the longevity promoting activity of sesamin are possibly due to its action as a hormetin by inducing oxidative stress response-mediated hormesis. It was concluded that sesamin extended the mean lifespan and alleviated the neurodegeneration in Drosophila melanogaster at least mediated by its interaction with genes SOD1, SOD2, CAT, and Rpn11, but not with gene Mth.
    Biogerontology 01/2013; DOI:10.1007/s10522-012-9413-4 · 3.01 Impact Factor
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    ABSTRACT: Interest in Tartary buckwheat as a cholesterol-lowering functional food is increasing. The present study was to (i) investigate the relative hypocholesterolemic activity of Tartary buckwheat flour compared with that of wheat and rice flour; and (ii) study the interaction of these three flours with gene expression of sterol transporters and proteins involved in cholesterol absorption. Thirty-six male hamsters were divided into four groups fed either the control or one of three experimental diets containing 24% respective flour, for a period of 6 weeks. Results showed that Tartary buckwheat flour but no wheat and rice flours reduced plasma total cholesterol (TC) and non-high-density lipoprotein cholesterol (non-HDL) as well as hepatic cholesterol concentrations. Compared with that of wheat and rice flours, supplementation of Tartary buckwheat flour into diet led to greater neutral sterol excretion and lesser mRNA of intestinal Niemann-Pick C1 Like 1 (NPC1L1) and acyl-CoA: cholesterol acyltransferase 2 (ACAT2). It was therefore concluded that Tartary buckwheat flour was hypocholesterolemic via inhibition of cholesterol absorption, most likely mediated by down-regulation of intestinal NPC1L1 and ACAT2.
    Journal of Functional Foods 01/2013; 6(1). DOI:10.1016/j.jff.2013.10.020 · 4.48 Impact Factor
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    ABSTRACT: Black rice is rich in anthocyanin antioxidants. The present study investigated the lifespan-prolonging activity of black rice extracts (BREs) and its effect on gene expressions of CuZnSOD (SOD1), MnSOD (SOD2), catalase (CAT), methuselah (Mth) and Rpn11 involved in the antioxidant system and ageing of fruit flies. The OR wild type fly was maintained on a control diet or two experimental diets containing 10 mg ml(-1) BRE (BRE10) or 30 mg ml(-1) BRE (BRE30). Results demonstrated that BRE30 could prolong the mean lifespan of fruit flies by 14%, accompanied with up-regulation of mRNA SOD1, SOD2, CAT and Rpn11, and with down-regulation of Mth. It was also found that BRE30 could attenuate the paraquat-induced neurodegeneration in OR wild type flies accompanied by up-regulation of SOD1, SOD2, CAT and Rpn11. In addition, BRE30 supplementation increased the survival time of OR wild type flies and Alzheimer transgenic flies Aβ42 33769 with chronic exposure to paraquat. It was concluded that BREs could extend the lifespan of fruit flies, most likely by regulating the genes of SOD1, SOD2, CAT, Mth and Rpn11 at the transcriptional level.
    08/2012; 3(12). DOI:10.1039/c2fo30135k
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    ABSTRACT: To investigate the effect of dietary calcium on plasma lipoprotein profile in castrated and ovariectomized hamsters. Male, castrated, female and ovariectomized hamsters (n=36 each group) were randomly divided into three sub-groups (n=12) and fed one of the three diets containing 0, 2, and 8 g calcium per kg diet for a period of six weeks. Changes in plasma lipoprotein profile were monitored at the end of week 0, 3 and 6. Plasma total cholesterol (TC), non-high density lipoprotein cholesterol (non-HDL-C), triacylglycerols (TG) and TC/HDL-C were decreased only in intact female and ovariectomized hamsters. In contrast, three levels of dietary calcium had no effect on lipoprotein profiles in both intact male and castrated hamsters. Beneficial modification of lipoprotein profile by dietary calcium was gender-dependent at least in hamsters.
    Biomedical and Environmental Sciences 08/2012; 25(4):392-8. DOI:10.3967/0895-3988.2012.04.003 · 1.26 Impact Factor
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    ABSTRACT: PURPOSE: The present study investigated the underlying mechanism associated with the hypocholesterolemic activity of blueberry anthocyanins by examining its effect on fecal sterol excretion and gene expression of major receptors, enzymes, and transporters involved in cholesterol metabolism. METHODS: Hamsters were divided into three groups and fed a 0.1 % cholesterol diet containing 0 % (CTL), 0.5 % (BL), and 1.0 % (BH) blueberry anthocyanins, respectively, for six weeks. Plasma total cholesterol (TC), triacylglycerols (TAG), and non-high-density lipoproteins cholesterol (non-HDL-C) were measured using the enzymatic kits, and the gene expression of transporters, enzymes, and receptors involved in cholesterol absorption and metabolism was quantified using the quantitative PCR. GC analysis was used to quantify hepatic cholesterol and fecal acidic and neutral sterols. RESULTS: Dietary supplementation of 0.5 and 1.0 % blueberry anthocyanins for 6 weeks decreased plasma TC concentration by 6-12 % in a dose-dependent manner. This was accompanied by increasing the excretion of fecal neutral and acidic sterols by 22-29 % and 41-74 %, respectively. Real-time PCR analyses demonstrated that incorporation of blueberry anthocyanins into diet down-regulated the genes of NPC1L1, ACAT-2, MTP, and ABCG 8. In addition, blueberry anthocyanins were also able to down-regulate the gene expression of hepatic HMG-CoA reductase. CONCLUSION: The cholesterol-lowering activity of blueberry anthocyanins was most likely mediated by enhancing the excretion of sterols accompanied with down-regulation on gene expression of intestinal NPC1L1, ACAT-2, MTP, and ABCG 8.
    European Journal of Nutrition 06/2012; 52(3). DOI:10.1007/s00394-012-0393-6 · 3.84 Impact Factor
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    ABSTRACT: Interest in replacing synthetic antioxidants, namely, butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA), with natural antioxidants is increasing. The present study examined the antioxidant activity of capsaicinoid from chili pepper in heated canola oil. The oxidation was conducted at 60, 90, 120, and 180 °C by monitoring oxygen consumption and the decrease in linoleic acid and α-linolenic acid in canola oil. At 60 °C, capsaicinoid was more effective against oxidation of canola oil compared with BHT. At higher temperatures of 90, 120, and 180 °C, capsaicinoid possessed an antioxidant activity similar to or slightly weaker that that of BHT. It was found that capsaicinoid prevented canola oil from oxidation in a dose-dependent manner. To study the structure-antioxidant relationship, it was found that the trimethylsiloxy (TMS) derivatives of capsaicinoid did not exhibit any antioxidant activity, suggesting the hydroxyl moiety was the functional group responsible for the antioxidant activity of capsaicinoid. It was concluded that capsaicinoid had the potential to be further explored as a natural antioxidant in foods, particularly spicy foods.
    Journal of Agricultural and Food Chemistry 05/2012; 60(24):6230-4. DOI:10.1021/jf301744q · 3.11 Impact Factor
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    ABSTRACT: PURPOSE: Capsaicinoids are the active compounds in chili pepper. The present study investigated the effect of capsaicinoids on plasma lipids, functionality of aorta including atherosclerotic plaque development, cholesterol absorption biomarker, fecal sterol excretion, and gene expression of major receptors, enzymes, and transporters involved in cholesterol metabolism. METHODS: Hamsters were divided into five groups and fed a high-cholesterol diet containing 0 % (CON), 0.010 % (LD), 0.015 % (MD), 0.020 % (HD), and 0.030 % (VD) capsaicinoids, respectively, for 6 weeks. Plasma lipids were measured using the enzymatic kits, and the gene expression of transporters, enzymes, and receptors involved in cholesterol absorption and metabolism was quantified using the quantitative PCR. Endothelial function was assessed by measuring the acetylcholine-induced endothelium-dependent relaxations in aorta. RESULTS: Capsaicinoids reduced plasma total cholesterol, non-high-density lipoprotein cholesterol, and triacylglycerols with high-density lipoprotein cholesterol being unaffected. All four experimental groups had a decrease in the atherosclerotic plaque compared with CON. Dietary capsaicinoids increased the fecal excretion of total acidic sterols possibly mediated by up-regulation of cholesterol 7α-hydroxylase and down-regulation of liver X receptor alpha. Plasma sterol analysis demonstrated that capsaicinoids decreased the ratio of plasma campesterol/cholesterol, suggesting they decreased cholesterol absorption. Capsaicinoids could improve the endothelium-dependent relaxations and reduce the endothelium-dependent contractions by inhibiting the gene expression of COX-2. However, no dose-dependent effect of capsaicinoids on these parameters was seen. CONCLUSION: Capsaicinoids were beneficial in improving lipoprotein profile and aortic function in hamsters fed a high-cholesterol diet.
    European Journal of Nutrition 03/2012; 52(1). DOI:10.1007/s00394-012-0344-2 · 3.84 Impact Factor