Inhibitory effects of Hibiscus sabdariffa L extract on low‐density lipoprotein oxidation and anti‐hyperlipidemia in fructose‐fed and cholesterol‐fed rats

Hibiscus sabdariffa L extract (HSE) is an aqueous extract of Hibiscus sabdariffa L flowers that is used as a local soft drink and medical herb in Taiwan. Oxidation of low‐density lipoprotein (LDL) has been shown to increase the incidence of atherosclerosis. In this study, we determined the antioxidative activity of HSE on LDL oxidation by examining relative electrophoretic mobilities (REM) and thiobarbituric acid‐reactive substances (TBARS). The data revealed an inhibitory effect of HSE on Cu²⁺‐mediated REM and TBARS. HSE exhibited a remarkable ability to reduce cholesterol degradation and ApoB fragmentation. Overall, HSE showed a high potency to inhibit the production of oxidized LDL induced by copper and, specifically, to reduce serum triglycerides in high‐fructose diet (HFD) fed rats and serum cholesterol in high‐cholesterol diet (HCD) fed animals. The levels of LDL and the ratio of LDL‐cholesterol (LDL‐C) to HDL‐cholesterol (HDL‐C) were reduced by HSE in both hyperlipidaemia models. Based on these findings, we suggest that HSE may be used to inhibit LDL oxidation and to prevent various types of hyperlipidaemia in HFD‐ or HCD‐fed rats. Copyright © 2004 Society of Chemical Industry     

Choosing hamsters but not rats as a model for studying plasma cholesterol‐lowering activity of functional foods

Rats and hamsters are commonly used rodents to test the efficacy of cholesterol‐lowering functional foods. In general, a diet containing 1% cholesterol for rats whereas a diet containing 0.1% cholesterol for hamsters is used to induce the hypercholesterolemia. The present study was carried out to compare hamsters with rats as a hypercholesterolemia model. Golden Syrian hamsters and Sprague Dawley rats were randomly divided into four groups and fed one of the four diets containing 0–0.9% cholesterol. Results demonstrated that serum total cholesterol (TC) in hamsters was raised 73–81% higher than that in rats fed the same cholesterol diets. Unlike rats in which HDL‐C accounted very little for serum TC, the lipoprotein profile in hamsters was closer to that in humans. We investigated interaction of higher cholesterol diets with 3‐hydroxy‐3‐methylglutary‐CoA (HMG‐CoA) reductase, low‐density lipoprotein receptor (LDL‐R) and cholesterol‐7α‐hydroxylase (CYP7A1), sterol regulatory element binding protein‐2 (SREBP‐2), and liver X receptor (LXR‐α). Results showed hamsters and rats metabolized cholesterol differently. In view that hamsters synthesize and excrete cholesterol and bile acids in a manner similar to that in humans, it is concluded that hamsters but not rats shall be chosen as a model to study efficacy of cholesterol‐lowering functional foods.     

EFFECTS OF ORAL CHONDROITIN SULFATE ON LIPID AND ANTIOXIDANT METABOLISMS IN RATS FED A HIGH-FAT DIET

This study aimed at determining the effects of purified chondroitin sulfate (ChS) from pig laryngeal cartilage on the lipid and antioxidant metabolisms of male Sprague‐Dawley rats that are fed a high‐fat diet. Thirty‐two male rats were divided into four groups and fed for 5 weeks on a standard diet, a high‐fat diet or a high‐fat diet plus ChS. It was demonstrated that the high‐fat diet provoked lipid peroxidation and induced a severe depletion of lipoprotein lipase, hepatic lipidase, glutathione, catalase and superoxide dismutase levels. ChS was effective in reducing triglycerides, total cholesterol, low‐density‐lipid cholesterol and malondialdehyde levels elevated by the high‐fat diet. In addition, ChS might reduce the risk of atherosclerosis, as high‐density‐lipid cholesterol, lipoprotein lipase, hepatic lipidase and the ratio of high‐density‐lipoprotein cholesterol to total cholesterol were significantly higher than in the high‐fat‐diet rats. ChS restored the endogenous antioxidants glutathione, catalase and superoxide dismutase. These results showed that ChS was potent in lipid‐lowering and altering the antioxidative enzyme; however, excess ChS would disturb lipid profiles that went beyond the normal limits.     

Hypolipidemic Activity of Peony Seed Oil Rich in α‐Linolenic,is Mediated Through Inhibition of Lipogenesis and Upregulation of Fatty Acid β‐Oxidation

Peony seed oil (PSO) is a new resource food rich in α‐Linolenic Acid(ALA) (38.66%). The objective of this study was to assess the modulatory effect of PSO on lipid metabolism. Lard oil, safflower oil (SFO), and PSO were fed to wistar rats with 1% cholesterol in the diet for 60 d. Serum and liver lipids showed significant decrease in total cholesterol (TC), triglyceride (TG), and low density lipoprotein‐cholesterol (LDL‐C) levels in PSO fed rats compared to lard oil and SFO fed rats. ALA, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), contents were significantly increased, whereas linoleic acid (LA), arachidonic acid (AA) levels decreased in serum and liver of PSO fed rats. Feeding PSO increased ALA level and decreased n‐6 to n‐3 polyunsaturated fatty acid (PUFA) ratio. The hypolipidemic result of PSO indicated that PSO participated in the regulation of plasma lipid concentration and cholesterol metabolism in liver. The decreased expression of sterol regulatory element‐binding proteins 1C (SREBP‐1c), acetyl‐CoA carboxylase (ACC), and fatty acid synthase (FAS)‐reduced lipid synthesis; Activation of peroxisome proliferator–activator receptor (PPARα) accompanied by increase of uncoupling protein2 (UP2) and acyl‐CoA oxidase (AOX) stimulated lipid metabolism and exerted an antiobesity effect via increasing energy expenditure for prevention of obesity.     

Lipid‐lowering mechanism of egg yolk in normal rats

The ingestion of egg has been reported to lower blood cholesterol, but the mechanism is unclear. Here, the biochemical metabolic mechanism by which the oral administration of egg yolk affects blood lipid reduction was investigated using normal rats. Blood triglycerides and total cholesterol were lower and high‐density lipoprotein cholesterol was higher in an egg yolk‐given group compared to other groups, while low‐density lipoprotein cholesterol was increased in the pork belly oil‐given group. HMG‐CoA reductase activity was higher in the pork belly oil‐given group, compared to an egg yolk‐given group, a weekly alternating administration of pork belly oil and egg yolk‐given group, and the saline‐given normal control group. However, faecal excretions of total sterol, neutral sterol and acid sterol in an egg yolk‐given group were higher compared to the pork belly oil‐given group, a weekly alternating administration of pork belly oil and egg yolk‐given group, and a normal control group. The results suggested that ingestion of egg decreased blood lipids.     

Mulberry extract inhibits the development of atherosclerosis in cholesterol-fed rabbits

Mulberry (Morus alba L.) fruit is used effectively in Chinese medicines against fever, to protect the liver and to lower blood pressure. Here, we report a water extract, MWE (Mulberry water extract), which is designed to exhibit anti-hyperlipidemia and anti-atherosclerotic effects in rabbits with experimental atherosclerosis. New Zealand white rabbits were fed with a normal diet, high cholesterol (1.3%), lard oil (3%) diet (HCD) with or without 0.5 or 1% MWE for 10 weeks. The levels of triglyceride, cholesterol and low-density lipoprotein cholesterol (LDL-C) were lower in the serum of rabbits fed HCD plus MWE than in the serum of rabbits fed HCD. Feeding MWE (0.5 or 1% in the diet) to rabbits significantly reduced severe atherosclerosis in the aorta by 42–63%. Histopathological examination showed that MWE reduced aortic atherosclerotic lesion in the blood vessel of rabbits. From previous data and present results, we suspect that MWE not only inhibits LDL-oxidation but also has a direct effect on the anti-hyperlipidemia in animals.     

Effects of the Polysaccharide from the Sporophyll of Brown Alga Undaria Pinnatifida on Serum Lipid Profile and Fat Tissue Accumulation in Rats Fed a High‐Fat Diet

We investigated the effects of the polysaccharide from the sporophyll of a selected brown alga Undaria pinnatifida on serum lipid profile, fat tissue accumulation, and gastrointestinal transit time in rats fed a high‐fat diet. The algal polysaccharide (AP) was prepared by the treatment of multiple cellulase‐producing fungi Trichoderma reesei and obtained from the sporophyll with a yield of 38.7% (dry basis). The AP was mostly composed of alginate and fucoidan (up to 89%) in a ratio of 3.75:1. The AP was added to the high‐fat diet in concentrations of 0.6% and 1.7% and was given to male Sprague–Dawley rats (5‐wk‐old) for 5 wk. The 1.7% AP addition notably reduced body weight gain and fat tissue accumulation, and it improved the serum lipid profile, including triglycerides, total cholesterol, and very low‐density lipoprotein‐cholesterol. The effects were associated with increased feces weight and shortened gastrointestinal transit time. In addition, the lipid peroxidation of the liver was decreased in both groups.     

植物甾醇对高血脂大鼠血脂水平的影响

目的：通过体内给药动物实验探讨植物甾醇的降血脂功效。方法：将雄性SD大鼠随机分为5组,分别饲喂基础饲料(正常组)、高脂饲料(模型组)和添加质量分数为0.5%、1.0%、2.0%植物甾醇的高脂饲料(剂量组),检测相关指标。结果：饲喂高脂饲料的干预组总胆固醇(TC)、甘油三酯(TG)和非高密度脂蛋白胆固醇(non-HDL-C)水平较模型组显著降低(P＜0.01),高密度脂蛋白胆固醇(HDL-C)水平显著升高(P＜0.01),且随着植物甾醇添加量的增加呈现一定的剂量效应。模型组胆碱酯酶(CHE)活力在血清及肝脏中显著降低(P＜0.01),剂量组CHE活力随着植物甾醇剂量的增加而升高。结论：植物甾醇对高血脂症大鼠血脂水平具有显著降低作用,并且具有抑制脂质过氧化和保护肝脏的作用。     

甘薯抗性淀粉对高脂血症大鼠降脂利肝作用研究

目的：考察甘薯抗性淀粉(SPRS)在大鼠形成高脂血症过程中的降血脂及促进肝损伤修复的作用。方法：取健康成年SD大鼠,雌雄各半,40只随机分为4组：正常对照组(NG)、高脂模型组(HL)、甘薯抗性淀粉低剂量组(SPRSL)、甘薯抗性淀粉高剂量组(SPRSH)。正常对照组饲喂基础饲料,高脂模型组饲喂高脂饲料,甘薯抗性淀粉组在高脂饲料的基础上分别给予甘薯抗性淀粉10、20g/(kg·d),45d后测定大鼠血清中总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)的含量及观察肝脏组织细胞形态变化。结果表明：甘薯抗性淀粉能显著降低TC、TG、LDL-C水平,提高HDL-C水平;甘薯抗性淀粉组肝细胞变性和坏死现象明显轻于高脂模型组。结论：甘薯抗性淀粉对高脂饲料致高脂血症大鼠的血脂水平有较好的调节作用,并明显改善大鼠的肝功能。     

Cholesterol lowering and vascular protective effects of ethanolic extract of dried fruit of Crataegus pinnatifida,hawthorn (Shan Zha), in diet-induced hypercholesterolaemic rat model

Consumption of functional foods for managing plasma cholesterol level has gained acceptance globally. The hypocholesterolaemic and vascular protective effects of the dried fruit of Crataegus pinnatifida, hawthorn (Shan Zha), were investigated in rats fed with normal diet, high cholesterol diet (HCD) or HCD plus Shan Zha 80% ethanolic extract treatment (30 or 100 mg/kg/day, p.o.) for 4 weeks. Shan Zha extract markedly reversed the increased plasma total cholesterol and high density lipoprotein cholesterol induced by HCD with a dose-dependent improvement on the atherogenic index. It also demonstrated good hepatoprotective function by reducing lipid content in the liver. The blunted endothelium-mediated aortic relaxation in HCD-fed rats was restored by high dosage of Shan Zha extract treatment. The current results showed that Shan Zha extract could provide its cholesterol lowering effect by up-regulating hepatic CYP7A1 mRNA expression which leads to enhanced bile acid biosynthesis. It is postulated that the hypocholesterolaemic effect is the primary beneficial effect given by Shan Zha extract; it then leads to other secondary beneficial effects such as vascular protective and hepatoprotective functions. Thus, Shan Zha extract could provide an overall improvement on the hepatic and vascular systems that may be important in relieving hypercholesterolaemia-related complications.     

Effects of dietary fibre‐ and polyphenol‐rich grape products on lipidaemia and nutritional parameters in rats

The aim of this work was to evaluate the effects of three dietary fibre‐ and polyphenol‐rich materials obtained from grapes on serum cholesterol, lipoprotein and triglyceride concentrations as well as on body weight, fat and protein digestibility in adult Wistar rats fed on cholesterol‐free and 10 g kg⁻¹ cholesterol‐added diets. Dietary fibre content of materials ranged from 540 to 590 g kg⁻¹. Intake of grape products increased stool weight and the amount of fat and protein excreted in faeces, but did not affect negatively animal growth or protein efficiency of the diet in Wistar rats. Studied grape fractions lower serum total cholesterol and LDL cholesterol concentrations in hypercholesterolemic rats. These results could be taken into account in potential applications of these products as a food ingredient. © 2000 Society of Chemical Industry     

Dietary calcium decreases plasma cholesterol by down‐regulation of intestinal Niemann–Pick C1 like 1 and microsomal triacylglycerol transport protein and up‐regulation of CYP7A1 and ABCG 5/8 in hamsters

Scope: It has been shown that calcium supplementation favorably modifies plasma lipoprotein profile in postmenopausal women. The present study investigated the interaction of dietary calcium with genes of transporters, receptors and enzymes involved in cholesterol metabolism. Methods and results: Forty‐eight ovariectomized hamsters were fed one of the four diets containing 0, 2, 6 and 8 g calcium per kg. Plasma total cholesterol (TC), triacylglycerols (TG), and non‐high density lipoprotein cholesterol were dose‐dependently decreased, whereas high‐density lipoprotein cholesterol (HDL‐C) was dose‐dependently increased with the increasing dietary calcium levels. Dietary calcium had no effect on protein mass of hepatic sterol regulatory element binding protein‐2 (SREBP), liver X receptor‐alpha (LXR), 3‐hydroxy‐3‐methylglutaryl‐CoA reductase (HMGR), LDL receptor (LDLR) and cholesterol‐7α‐hydroxylase (CYP7A1). However, dietary calcium up‐regulated the mRNA levels of hepatic CYP7A1 and intestinal ATP binding cassette transporters (ABCG5/8) whereas it down‐regulated the intestinal Niemann‐Pick C1 like 1 (NPC1L1) and microsomal triacylglycerol transport protein (MTP). In addition, dietary calcium increased the activity of intestinal acyl coenzyme A: cholesterol acyltransferase 2, while it decreased plasma cholesteryl ester transport protein (CETP). Conclusion: Beneficial modification of lipoprotein profile by dietary calcium was mediated by sequestering bile acid absorption and enhancing excretion of fecal cholesterol, via up‐regulation of mRNA CYP7A1 and intestinal ABCG 5/8 with down‐regulation of mRNA NPC1L1 and MTP.     

火麻籽多肽对高脂饮食喂养大鼠血脂的影响

目的：通过动物实验对火麻籽多肽进行降血脂功能性进行研究。方法：选取60 只SD雄性大鼠,适应性饲养1 周后,分成正常对照组（10 只）、模型组（50 只）,正常对照组给予基础饲料,模型组饲喂高脂饲料,连续饲喂4 周建立高血脂模型大鼠;造模成功后将模型组平均分为高脂模型组、阳性对照组（辛伐他汀,10 mg/kg mb）和火麻籽多肽低（200 mg/kg mb）、中（400 mg/kg mb）、高（800 mg/kg mb）剂量组,分别经口灌胃饲喂4 周后测定大鼠体质量,脏器指数,血清中总胆固醇（total cholesterol,TC）、甘油三酯（triglyceride,TG）、高密度脂蛋白胆固醇（high-density lipoprotein cholesterol,HDL-C）和低密度脂蛋白胆固醇（low-density lipoprotein cholesterol,LDL-C）、谷草转氨酶（aspartate aminotransferase,AST）、谷丙转氨酶（alanine aminotransferase,ALT）水平,血液流变学变化,肝脏病理切片组织形态学变化。结果表明：与高脂模型组相比,火麻籽多肽能够抑制大鼠的体质量增长,降低肝脏指数和血清中TC、TG、LDL-C、AST、ALT水平,升高HDL-C水平,降低动脉硬化指数,改善大鼠血流变学指标,降低大鼠的全血黏度和血浆黏度;改善肝脏脂肪变性情况。结论：火麻籽多肽对高脂饮食喂养大鼠具有一定的降脂作用。     

高脂饮食诱导高脂血症大鼠及不同器官病理变化

通过高脂饮食建立高脂血症大鼠模型,观察高脂血症大鼠体内程序性死亡受体1(PD-1)的表达变化。将40只雄性SD大鼠分为2组,分别饲喂普通饲料和高脂饲料12周,计算大鼠的肝脏、脾脏和胰腺指数,测定大鼠全血血糖,检测大鼠血清中甘油三酯(TG)、总胆固醇(T-CHO)、高密度脂蛋白胆固醇(HDL-C)和低密度脂蛋白胆固醇(LDL-C)的含量,通过HE染色检测大鼠肝脏的病理变化,同时采用RT-q PCR检测PD-1 mRNA在大鼠肝脏、脾脏和胰腺组织内的表达变化。结果表明:高脂饲料组大鼠的肝脏、脾脏和胰腺指数显著高于普通饲料组;高脂饲料组大鼠的血糖显著升高;高脂饲料组大鼠血清中的TG、T-CHO、LDL-C的含量均显著高于普通饲料组,LDLC/HDL-C的比值也显著高于普通饲料组,高脂血症大鼠造模成功。HE染色显示高脂饲料组大鼠肝脏组织内均出现明显脂肪空泡。与普通饲料组相比,高脂饲料组大鼠肝脏、脾脏和胰腺组织内PD-1 mRNA的表达均显著降低,提示PD-1可能参与了高脂血症的发生和发展。     

EFFECT OF DIETARY MILK CREAM AND EGG YOLK FAT ON SERUM AND LIVER LIPID PROFILE IN RATS

Influence of dietary fat from milk and egg yolk on serum and liver lipid profile was studied in rats. Rats fed milk fat at 5% level for 8 weeks showed a 17% decrease in serum cholesterol and 31% decrease in triacylglycerol compared to the control group of rats fed groundnut oil (GNO). Liver cholesterol was decreased by 20% in the milk fed group. There was no difference in serum cholesterol concentration of rats fed egg yolk compared to the control animals. However, triacylglycerol and phospholipids in serum of rats fed egg yolk were decreased by 20 and 24%, respectively. In another set of experiments animals were rendered hypercholesterolemic by feeding a diet containing 0.5% cholesterol. Addition of milk fat in the diet decreased serum and liver cholesterol by 11 and 17%, respectively, compared to rats fed on a control diet. Similarly, triacylglycerols were decreased by 23 and 8%, respectively, in serum and liver of animals given     

Whole grains and resistant starch rich,reduced‐calorie biscuit diet as a hypoglycaemic,hypolipidaemic and insulin stimulator in streptozotocin‐induced diabetic rats

A fibre‐enriched, reduced‐calorie biscuit [formulated biscuit (FB)] was evaluated for its antidiabetic and antilipidaemic potential in streptozotocin‐induced diabetes in Wistar rats against control biscuit (CB) having high calorie and low fibre content. Animals were allocated into five groups: a control group fed with synthetic diet, two diabetes‐induced groups (CBD and FBD) and two nondiabetic groups (CBND and FBND). CBD and CBND were fed with synthetic diet + CB while FBD and FBND were fed with synthetic diet + FB. After 6 weeks of feeding, the change in weight of nondiabetic group fed with FB (+16.20%) was nonsignificantly lower compared to control (+33.01%) and CB‐fed (+34.55%) group. Nonsignificant loss in body weight was observed among diabetic group fed with FB (?11.76%) or CB (?36.88%). Feeding of FB led to a significant decrease in fasting and postprandial blood glucose levels, total cholesterol, triglycerides, LDL‐C, VLDL‐C and atherosclerotic index and increase the HDL‐C. Histological examination showed that feeding of FB was able to partially recover the destroyed β‐cell in STZ‐induced diabetic rats.     

Effect of lupeol and lupeol linoleate on lipemic--hepatocellular aberrations in rats fed a high cholesterol diet

Cholesterol feeding has been often used to study the etiology of hypercholesterolaemia-related metabolic disturbances. The aim of the present study is to investigate the effects of a pentacyclic triterpene, lupeol, and its ester derivative on hepatic abnormalities associated with hypercholesterolemic rats. Hypercholesterolaemia was induced in male Wistar rats by feeding them with a high cholesterol diet (HCD) containing normal rat chow supplemented with 4% cholesterol and 1% cholic acid, for 30 days. Lupeol and lupeol linoleate were supplemented (50 mg/kg body wt/day) during the last 15 days. Increased hepatic lipid profile along with abnormalities in lipid-metabolizing enzyme activities were seen in hypercholesterolemic rats. An apparent increase in the expression of Acyl-CoA cholesterol acyltransferase mRNA was seen in HCD fed rats. The activities of hepatic marker enzymes, which serve as indices of cellular injury, were altered in HCD fed rats. Treatment with triterpenes significantly modulated the abnormalities induced by hypercholesterolaemia. Also, an increased (P >0.001) faecal excretion of cholesterol and bile acids were observed in lupeol and lupeol linoleate group when compared with HCD fed group. Therefore, it can be concluded that triterpenes treatment afforded substantial protection against the anomalies, which are manifested during the early stage of hypercholesterolemic atherogenesis.     

Enhanced cholesterol‐ and triglyceride‐ lowering effect of West African green tea

‘The Vert’ is a special type of green tea widely consumed in West Africa and locally associated with many health benefits. However, limited research has been conducted to evaluate its health benefits, such as its enhanced hypolipidemic potential. The objectives of this study were to (1) evaluate the cholesterol‐ and triglyceride‐lowering effects of West African green tea (WAGT) as affected by diet and tea intake, (2) determine the impact of WAGT consumption on the CHD risk ratio, and (3) explore possible mechanisms through which WAGT improves serum lipid profile. Forty‐five male Wistar rats were randomly assigned to one of nine treatment combinations, three diets (regular, high‐cholesterol, and trans‐fat diets) and three fluid sources (no tea, diluted tea, and concentrated tea). After 6 weeks of feeding, animal blood, liver, and feces were harvested. Total cholesterol, HDLc, LDLc, and triglycerides in serum, liver, and feces were determined. The concentrations of bile acids in feces were also measured. WAGT significantly lowered serum and liver cholesterol (30% and 15%, respectively) and increased serum HDL cholesterol (30%). It also reduced liver enlargement caused by storage of excess lipids in high‐cholesterol diet. Overall, the CHD risk ratio was cut by two‐thirds in rats fed high‐cholesterol diet and WAGT. A marked increase in fecal total lipids, cholesterol (60%), and bile acids (50%) was observed in rats that consumed WAGT compared to the control group. These beneficial effects could be attributed to the significantly high flavonoid content of WAGT. Copyright © 2007 Society of Chemical Industry     

Hypolipidaemic effects of synbiotic yoghurt in rabbits

The hypolipidaemic effects of synbiotic yoghurt prepared using Lactobacillus acidophilus, fructooligosaccharide (FOS) and isomaltooligosaccharide (IMOS) were assessed through biological study. Hyperlipidaemia‐induced rabbits were fed on a diet containing different levels of synbiotic yoghurt, and the blood of the animals was analysed for lipid profile on a weekly basis. There were significant reductions in total cholesterol (124.00 ± 7.10 mg/dL), triglycerides (155.00 ± 8.88 mg/dL), low‐density lipoprotein levels (13.27 ± 0.76 mg/dL) and very low‐density lipoprotein levels (57.04 ± 3.27 mg/dL), whereas high‐density lipoprotein levels (53.70 ± 0.35 mg/dL) were increased. On the basis of these results, it was concluded that the synbiotic yoghurt possessed a significant hypolipidaemic potential.