Effect of protein hydrolysates from sardinelle (Sardinella aurita) on the oxidative status and blood lipid profile of cholesterol-fed rats

This study was designed to test the hypolipidemic properties and antioxidative activities of sardinelle (Sardinella aurita) protein hydrolysates (SPHs) obtained by treatment with crude enzyme preparations from Bacillus pumilus A1(SPHA1), Bacillus mojavensis A21(SPHA21) and crude enzyme extract from sardinelle viscera (SPHEE).Wistar rats were fed during 7 weeks a standard laboratory diet, a cholesterol-enriched diet (1%) or a cholesterol SPH-enriched diet. The hypercholesterolemic diet induced the elevation of total cholesterol (TC), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C). Supplementing cholesterol-enriched diet with SPHs or whole sardinelle protein (WSP) at a concentration of 5% (w/w) increased the serum level of high-density lipoprotein cholesterol (HDL-C) and HDL-C/TC ratio and decreased the serum levels of TC, TG, LDL-C and LDL-C/HDL-C ratio significantly.The thiobarbituric acid-reactive substances (TBARS) level, as an indicator of lipid peroxidation, and the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) were examined. The hepatic antioxidant enzymes activities were significantly decreased and the malondialdehyde (MDA) level was increased in rats fed a cholesterol-enriched diet compared to those fed a standard diet. The treatment of hypercholesterolemic (HCD) diet rats with SPHs reduced the MDA concentration and increased the antioxidant enzyme activities.These results suggested that the hypolipidemic effect of SPHs might be due to their abilities to lower serum TC, TG, and LDL-C levels as well as to their antioxidant activities preventing the lipid peroxidation process.     

β-Conglycinin (7S) and glycinin (11S) exert a hypocholesterolemic effect comparable to that of fenofibrate in rats fed a high-cholesterol diet

The hypocholesterolemic effect of isolated soybean proteins and fenofibrate in rats was compared. Forty-five rats were divided into five groups: standard (STD; casein), high cholesterol (HC; STD plus 1% cholesterol/0.5% cholic acid), HC + β-conglycinin, HC + glycinin and HC + fenofibrate. The proteins and the drug were administered by gavage for 28 days. The proteins decreased total cholesterol (TC) and triacylglycerol (TG) in the plasma of the rats fed HC diet, to values very close to those fed on fenofibrate. High density lipoprotein cholesterol (HDL-C) levels in the plasma were increased by the β-conglycinin, glycinin and fenofibrate groups. The largest TC reduction in the liver was observed in the fenofibrate group; in contrast, the β-conglycinin and glycinin groups exhibited reduced the levels of hepatic TG and TC. Based on these data, it could be suggested that the oral daily administration of isolated soybean proteins, in the range of 2.75% of the protein ingested daily, can promote a reduction in TC and TG in the plasma of rats fed hypercholesterolemic diets.     

The role of dietary oxidized cholesterol and oxidized fatty acids in the development of atherosclerosis

The etiology of atherosclerosis is complex and multifactorial but there is extensive evidence indicating that oxidized lipoproteins may play a key role. At present, the site and mechanism by which lipoproteins are oxidized are not resolved, and it is not clear if oxidized lipoproteins form locally in the artery wall and/or are sequestered in atherosclerotic lesions following the uptake of circulating oxidized lipoproteins. We have been focusing our studies on demonstrating that such potentially atherogenic oxidized lipoproteins in the circulation are at least partially derived from oxidized lipids in the diet. Thus, the purpose of our work has been to determine in humans whether oxidized dietary oxidized fats such as oxidized fatty acids and oxidized cholesterol are absorbed and contribute to the pool of oxidized lipids in circulating lipoproteins. When a meal containing oxidized linoleic acid was fed to normal subjects, oxidized fatty acids were found only in the postprandial chylomicron/chylomicron remnants (CM/RM) which were cleared from circulation within 8 h. No oxidized fatty acids were detected in low density lipoprotein (LDL) or high density lipoprotein (HDL) fractions at any time. However, when alpha-epoxy cholesterol was fed to human subjects, alpha-epoxy cholesterol in serum was found in CM/RM and also in endogenous very low density lipoprotein, LDL, and HDL and remained in the circulation for 72 h. In vitro incubation of the CM/RM fraction containing alpha-epoxy cholesterol with human LDL and HDL that did not contain alpha-epoxy cholesterol resulted in a rapid transfer of oxidized cholesterol from CM/RM to both LDL and HDL. We have suggested that cholesteryl ester transfer protein is mediating the transfer. Thus, alpha-epoxy cholesterol in the diet is incorporated into CM/RM fraction and then transferred to LDL and HDL contributing to lipoprotein oxidation. We hypothesize that diet-derived oxidized fatty acids in chylomicron remnants and oxidized cholesterol in remnants and LDL accelerate atherosclerosis by increasing oxidized lipid levels in circulating LDL and chylomicron remnants. This hypothesis is supported by our feeding experiments in animals. When rabbits were fed oxidized fatty acids or oxidized cholesterol, the fatty streak lesions in the aorta were increased by 100%. Moreover, dietary oxidized cholesterol significantly increased aortic lesions in apo-E and LDL receptor-deficient mice. A typical Western diet is rich in oxidized fats and therefore could contribute to the increased arterial atherosclerosis in our population.     

Hypocholesterolemic effect of dietary evening primrose (Oenothera paradoxa) cake extract in rats

The objective of this study was to determine the effects of dietary evening primrose cake extract (E) on the lipid indices and lipid peroxidation products in growing rats fed cholesterol-free standard diet (S) or diets enriched with 1% cholesterol (C). All animals were divided into five groups of 10 and were fed during 4 weeks experimental diets: group (Gr) 1–standard diet (S); Gr 2–S diet supplemented with 1% E (S+1%E); Gr 3–with 1% C (S+1%C); Gr 4–S+1%C+0.5%E and Gr 5–S+1%C+1%E. Dietary E significantly decreased plasma total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) but did not change the high density lipoprotein cholesterol (HDL-C) either in rats fed cholesterol-free or enriched-in-cholesterol diets. Plasma TC were 98.7, 81.3, 144.6, 114.5 and 99.1 mg 100 ml⁻¹, whereas LDL-C values were 19.4, 7.6, 77.2, 43.6 and 27.6 mg 100 ml⁻¹ in Groups 1–5, respectively. Supplementation of diet with E significantly elevated triglyceride and phospholipid concentrations in the liver; also 1% E with C (S+1%C+1%E) caused significant TC accumulation in the liver and elevated malondialdehyde concentrations in plasma and erythrocytes. In conclusion, this study demonstrates, for the first time, that evening primrose cake extract (E) possesses strong hypocholesterolemic action. Its antioxidative properties, especially in animals loaded with dietary cholesterol, are less clear and need further studies..     

Effects of a black rice extract (Oryza sativa L. indica) on cholesterol levels and plasma lipid parameters in Wistar Kyoto rats

This study was designed to evaluate the efficacy of an anthocyanin pigmented rice (e.g. black rice) to mitigate the onset of hypercholesterolemia in rats-fed atherogenic diets. Male Wistar (n = 10/group) rats were fed with atherogenic diets containing 0.5% cholesterol in the presence and in the absence of bile salt (e.g. 0.05% cholic acid) along with a standardized black rice extract (BRE) (e.g. 3%, w/w). All animals were individually housed in stainless steel cages and fed with the experimental diets during a 12-h period for 10 weeks. Body weights of rats were measured every week of the experiment. After 10 weeks fed on experimental diets, rats were sacrificed and plasma total cholesterol, HDL and LDL cholesterol and triacylglycerols were measured immediately. The total cholesterol (TC) content in the liver, heart and aorta, and the concentration of triacylglycerol (TAG) were measured after lipid extraction using Folch method. Rats fed with 0.5% cholesterol containing diets which also included bile salt exhibited a considerably more severe hypercholesterolemia than counterparts fed diets containing only 0.5% cholesterol. The inclusion of the BRE in diets significantly (p < 0.05) decreased the level of TC, LDL–TC and TAG in plasma of rats-fed control diets that either contained or were absent in bile salt (p < 0.05). There were no differences in HDL-level. Liver crude lipids and total cholesterol levels were also significantly (p < 0.05) decreased in experimental groups relative to the control group in both experiments. Thus, supplementation of atherogenic experimental diets with BRE effectively decreased lipid levels in hypercholesterolemic rats. In lieu of the mixture of bioactive components present in BRE, it is possible that more than one mechanism underlying this reduction in lipids is involved.     

Effects of thymoquinone rich fraction and thymoquinone on plasma lipoprotein levels and hepatic low density lipoprotein receptor and 3-hydroxy-3-methylglutaryl coenzyme A reductase genes expression

The hypocholesterolemic effect of thymoquinone rich fraction (TQRF) extracted from Nigella sativa seeds using supercritical fluid extraction (SFE) in comparison with commercial available thymoquinone (TQ) in male Sprague–Dawley rats was investigated. Rats were fed prepared diet supplemented with 1% (w/w) cholesterol and treated with TQRF at, 0.5, 1 and 1.5 g/kg and TQ at 20, 50 and 100 mg/kg for 8 weeks. Plasma total cholesterol levels (TC) and low density lipoprotein cholesterol (LDLC) were significantly decreased in the TQRF and TQ treated rats compared to untreated rats. mRNA level of low density lipoprotein receptor (LDLR) was significantly expressed and the mRNA level of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-COAR) was significantly suppressed in the TQRF and TQ treated rats at different doses compared to untreated rats. These new findings identify TQRF and TQ as natural cholesterol lowering agents, and our study provides a molecular basis for the mechanisms of action through regulation of cholesterol in two main mechanisms first, uptake of LDLC via up regulation of LDLR gene and second, inhibition the synthesis of cholesterol via suppressing the HMG-COAR gene.     

Antihyperlipidemic effect of diosmin: A citrus flavonoid on lipid metabolism in experimental diabetic rats

The present study was hypothesized to evaluated the antihyperlipidemic effect of diosmin (DS) on lipid metabolism in experimental diabetic rats. Diabetes was induced male albino Wistar rats by intraperitoneal administration of streptozotocin (STZ) (45 mg/kg b.w.) 15 min after the ip administration of nicotinamide (NA) (110 mg/kg b.w.). DS were administered to diabetic rats intragastrically at 100 mg/kg b.w. for 45 days. The levels of plasma and tissue lipids (cholesterol, triglycerides) (TGs), free fatty acids (FFAs) and phospholipids (PLs), low density, very low-density lipoproteins (LDL and VLDL), and high-density-cholesterol (HDL-C) were measured. The activities of 3-hydroxy 3-methylglutaryl coenzyme A (HMG-CoA) reductase, lipoprotein lipase (LPL) and lecithin cholesterol acyl transferase (LCAT) were assayed. The levels of plasma and tissue lipids decreased with significant increase in HDL-C levels. The altered activities of lipid metabolic enzymes were restored to near normal. The present findings suggest that DS can potentially ameliorate lipid abnormalities in experimental diabetes.     

Effect of Lactobacillus-fermented adlay-based milk on lipid metabolism of hamsters fed cholesterol-enriched diet

The aim of this study was to investigate the effect of adlay milk and adlay-soymilk fermented with Lactobacillus plantarum or Lactobacillus paracasei on lipid metabolism in hamsters fed with a cholesterol-enriched diet. Adlay milk and fermented adlay milk with or without soymilk administered to hamsters significantly decreased (p < 0.05) serum cholesterol levels and ratio of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol, when compared to a high-cholesterol diet group; there was also a significant (p < 0.05) increase in the level of fecal cholesterol and triglycerides. The group administered adlay milk fermented with L. plantarum or L. paracasei presented increased superoxide dismutase and total antioxidant status activity in the blood, thus relieving the levels of thinobarbituric acid reactive substances as compared to other treatment groups. Adlay milk and Lactobacillus-fermented adlay milk with or without a soymilk supplement, could be used as a potential cholesterol-lowering ingredient; it could also relieve hyperlipidemia-induced oxidative stress to improve hypercholesterolemia.     

Effects of chestnut tannins on carcass characteristics,meat quality,lipid oxidation and fatty acid composition of rabbits

Seventy two male Bianca Italiana rabbits were used to study the effects of the inclusion (0%, 0.5%, and 1.0%) of a natural extract of chestnut wood (Silvafeed ENC) in the diet on productive traits, carcass characteristics, meat quality, lipid oxidation and fatty acid composition of rabbit meat. Results showed ENC had no significant effect on live weight, productive traits, hot carcass weight, dressing percentage, skin weight, pH, cooking losses, shear force and colour. The iron content was higher in Longissimus thoracis et lumborum (LTL) muscle of rabbit fed the ENC 1.0% diet than the control group. TBARS average values in the group ENC 0.5% were significantly lower (P < 0.05) than in the control and ENC 1.0% groups. Myristic acid (C14:0; P < 0.01), palmitoleic acid (C16:1 cis-9; P < 0.05) and pentadecanoic acid (C15:0; P < 0.01) contents were lower in LTL muscle of rabbits fed the ENC 1.0% diet, whereas the palmitic acid (C16:0) content was higher (P < 0.05) in the rabbits of this group. Moreover, the rabbits fed with the ENC 0.5% diet had lower (P < 0.01) levels of trans-vaccenic acid (C18:1 trans-11) compared to rabbits fed with the control diet. No significant differences were observed in saturated (SFA), monounsaturated (MUFA), polyunsaturated (PUFA) fatty acids, as well as in PUFA/SFA and n − 6/n − 3 ratios among the groups.     

Antiobesity and lipid lowering effects of theaflavins on high-fat diet induced obese rats

Theaflavins are major polyphenols in black tea. This study investigated antiobesity and lipid lowering effects of black tea extract (BTE), a highly purified theaflavins mixture (TFs, 83.84%) and theaflavin (TF1, 93.25%) on high-fat diet (HFD) induced obese rats. The body weight was slightly reduced by BTE and TFs (p > 0.05), and was significantly decreased by TF1 (p < 0.05) relative to the HFD control group. All samples remarkably decreased the food intake, adiposity index and the serum levels of total cholesterol (TC), triacylglycerol (TG) and low-density lipoprotein cholesterol (LDL-C) (p < 0.05), except that BTE and TF1 insignificantly decreased the TC concentration (p > 0.05). Moreover, administration of BTE, TFs and TF1 all significantly decreased atherogenic index (AI), enhanced insulin sensitive index (ISI), inhibited the hepatic lipase (HL) activity (p < 0.05), and slightly reduced leptin level in liver, decreased serum alanine transaminase (ALT) activity and increased serum superoxide dismutase (SOD) activity (p > 0.05) as compared to that of the HFD controls. These results indicated that theaflavins were one of the functional components which contributed to the antiobesity and lipid lowering effects of black tea, and might reduce the risk of type 2 diabetes and cardiovascular disease (CVD) in obese patients.     

Preventive effects of caffeic acid on lipids,lipoproteins and glycoproteins in isoproterenol induced myocardial infarcted rats

Dietary phenolic compound intake has been reported inversely related to the incidence of cardiovascular diseases. The aim of this research was to understand the preventive effects of caffeic acid, a phenolic acid on lipids, lipoproteins and glycoprotein components in isoproterenol induced myocardial infarcted rats. Rats were pretreated with caffeic acid (15 mg/kg body weight) daily for a period of 10 days. After pretreatment, rats were induced myocardial infarction by subcutaneous injection of isoproterenol (100 mg/kg body weight). Isoproterenol induced myocardial infarcted rats showed significant (P < 0.05) decreased levels of heart phospholipids and significant (P < 0.05) increased levels of serum and heart cholesterol, triglycerides, free fatty acids and serum phospholipids. Isoproterenol also significantly (P < 0.05) increased low density and very low density lipoprotein cholesterol and significantly (P < 0.05) decreased high density lipoprotein cholesterol levels. The activity of liver 3-hydroxy-3methyl glutaryl-coenzyme-A-reductase was significantly (P < 0.05) increased and lecithin cholesterol acyl transferase activity was significantly (P < 0.05) decreased in isoproterenol induced myocardial infarcted rats. In addition, the levels of glycoprotein components in the serum and heart were significantly (P < 0.05) increased in myocardial infarcted rats. Pretreatment with caffeic acid positively altered all the above mentioned biochemical parameters studied in isoproterenol induced myocardial infarcted rats.In conclusion, caffeic acid protected the rat's heart from the deleterious effects of lipids, lipoproteins and glycoproteins by its antilipidemic and antiglycative effects in isoproterenol induced myocardial infarcted rats. A diet containing caffeic acid may be beneficial to myocardial infarction.     

Suppression of diet-induced hypercholesterolaemia by saponins from Panax notoginseng in rats

Panax notoginseng saponins (PNS) are major active constituents of P. notoginseng. This study investigated the mechanisms of the hypocholesterolaemic and atheroscleroprotective effects of PNS. It was found that treatment of PNS (30 or 100 mg/kg/day, p.o.) could significantly reduce elevated serum total cholesterol, triacylglycerol, low-density lipoprotein cholesterol and atherogenic index induced by feeding rats with high cholesterol diet for 28 days. High-density lipoprotein cholesterol could also be increased by PNS treatment. Additionally, PNS significantly enhanced the hypercholesterolaemia-induced reduction of superoxide dismutase activity in the liver. In hypercholesterolaemic rats, PNS significantly improved the endothelium-dependent vasodilatation, acetylcholine-induced nitric oxide production and endothelial nitric oxide synthase mRNA expression in a dose-dependent manner. It also significantly reversed the hypercholesterolaemia-induced changes in mRNA expressions of cholesterol 7α-hydroxylase and peroxisome proliferator-activated receptor α but not HMG-CoA reductase. The findings provided evidence for using PNS to prevent the development of hypercholesterolaemia and atherosclerosis. The hypocholesterolaemic activity of PNS is likely to be resulted from inducing the biosynthesis of bile acids from cholesterol and promoting the β-oxidation of fatty acids in the liver. The vasoprotective function of PNS may be brought about by increasing the gene expression of eNOS in endothelial cells, its antioxidative activity, or both.     

Pinto bean hull extract supplementation favorably affects markers of bone metabolism and bone structure in mice

Hulls from dry edible beans are rich in phenolic compounds recognized as possessing antioxidant activity. The aim of this study was to characterize antioxidant properties of bean hull extract (BHE) and to determine whether BHE supplementation (at 400 or 800 mg/kg for 3 months) affects serum biochemical markers and bone structure in 12-month-old male C57BL/6 mice. Mice supplemented with 800 mg BHE/kg had lower serum tartrate-resistant acid phosphatase and parathyroid hormone concentrations than those on control diet or supplemented with 400 mg BHE/kg. BHE supplementation caused slight decrease in oxidized glutathione concentration in blood (P = 0.07). Compared to the control group, BHE supplementation at 800 mg/kg for 3 months improved bone structural indices, bone mineral density and trabecular thickness in the third lumbar vertebra. These results suggest that BHE supplementation may have beneficial effects on bone health in mice by decreasing bone resorption.     

Nigella sativa oil affects glucose metabolism and lipid concentrations in patients with type 2 diabetes: A randomized,double-blind,placebo-controlled trial

The aim of the present study was to determine the effects of Nigella sativa (NS) oil on glucose metabolism and lipid concentrations in patients with type 2 diabetes (T2DM). In this double-blind randomized controlled clinical trial, 72 volunteer subjects at Endocrinology Clinics of Kermanshah were recruited. Participants were patients aged 30–60 years old with T2DM. They were randomly divided into intervention (n = 36) and placebo groups (n = 36) and received 3 g/day (one three times a day) NS oil or sunflower soft gel capsules for 12 weeks. At baseline and at the end of the trial, anthropometric indices, dietary intake and biochemical parameters were measured. Sixty-seven patients completed the trial (intervention n = 34, placebo n = 33). Since the data analysis was based on intention-to-treat approach, all 72 subjects (36 in each group) were included for data analysis. Two groups were similar in the baseline characteristics. After the intervention, weight and body mass index decreased in the intervention group compared to the baseline, but it was not significant between the two groups. Dietary intake in both groups changed compared to baseline. Comparison of the two groups indicated that fasting blood sugar, glycated hemoglobin, triglyceride and low density lipoprotein–cholesterol changed significantly in intervention group compared to the placebo group (p < 0.05, adjusted for confounder factors). Insulin level and insulin resistance decreased and high density lipoprotein–cholesterol increased in the intervention group, but after adjusting for confounder factors, they were not significant. Supplementation with NS oil can improve glycemic status and lipid profile in patients with T2DM.     

Antioxidant,anti-inflammatory and DNA scission inhibitory activities of phenolic compounds in selected onion and potato varieties

Processing of onion and potato produces a large amount of discards, mainly skins. This study compared the antioxidant activity of skin and flesh phenolics of selected onion (Pearl, Red, Yellow and White) and potato (Purple, Innovator, Russet and Yellow) varieties. All tests were carried out separately for the soluble and insoluble-bound phenolic constituents of onion and potato samples. The potency of the phenolic extracts in the inhibition of radical-induced DNA scission, human low-density lipoprotein (LDL) cholesterol oxidation and LPS-stimulated cyclooxygenase-2 (COX-2) expression in J774A.1 mouse macrophage cells were monitored. Results showed that the soluble extracts had a higher phenolic content and antioxidant activity than the insoluble-bound extracts in most of the assays. Both onion and potato phenolics exhibited notable inhibition of LDL cholesterol oxidation, DNA scission and COX-2 expression at concentrations as low as 5 μg/mL. Pearl onion skin and Purple potato peel phenolics exhibited the highest activities among the tested onion and potato varieties, respectively.     

Polysaccharides from the green alga Ulva rigida improve the antioxidant status and prevent fatty streak lesions in the high cholesterol fed hamster,an animal model of nutritionally-induced atherosclerosis

We investigated the effects of Ulva in hypercholesterolemic hamsters, before and after processing. Three groups of 12 hamsters were fed a high cholesterol diet for 12 wk (Control) or a high cholesterol diet where cellulose has been replaced for an equivalent fibre weight from Ulva or processed Ulva. Plasma cholesterol, non-HDL cholesterol and specially triglycerides were reduced by Ulva. Liver glutathione peroxidase activity was increased and thiobarbituric acid reactive substances were efficiently reduced by dietary treatments compared with controls, whereas plasma antioxidant capacity was increased and aortic fatty streak area was decreased by 70%. The results show for the first time that chronic consumption of polysaccharides supplied by Ulva prevent the fall of antioxidant defences and the development of atherosclerosis in hamsters. The underlying mechanism is related mainly to increased antioxidant status although improvement of the serum lipid profile was not ruled out.     

Garlic oil attenuates the cardiac apoptosis in hamster-fed with hypercholesterol diet

Hypercholesterolemia is a well established risk factor for cardiac cell apoptosis. The purpose of this study is to evaluate the effects of garlic oil on cardiac apoptosis induced by a hypercholesterol diet.Twenty-four male Golden-Syrian hamsters at 3 months of age were randomly divided into three groups, control, cholesterol and garlic oil groups received a chow diet, chow diet with 2% cholesterol, and chow diet with 2% cholesterol and 1% garlic oil for 8 weeks, respectively.The TUNEL-positive apoptotic cells, and several apoptotic proteins were significantly induced in the excised left ventricle in cholesterol group, whereas significant reduction was observed in cholesterol plus garlic oil group. The IGFI receptor dependent survival pathway was inhibited in cholesterol group whereas it was obviously reversed in cholesterol plus garlic oil group. Our results suggest that administration of garlic oil shows protective effects on cardiac apoptosis in rats with high cholesterol intake.     

Effect of oral administration of water-soluble extract from citrus peel (Citrus unshiu) on suppressing alcohol-induced fatty liver in rats

Water-soluble citrus peel extract (WCE) from Citrus unshiu was studied for its anti-alcoholic fatty liver activities through chronic oral administration to Sprague Dawley (SD) rats. WCE, which was prepared by ultrasound-assisted extraction (UAE), was co-supplemented with ethanol (2.87 ml/rat/day) at low and high dosages (278 and 576 mg/rat/day, respectively) for 6 weeks. Ethanol consumption significantly elevated both total cholesterol (TC) and triglyceride (TG) concentrations in the serum of SD rats; otherwise co-administration of WCE lowered both serum TG and TC levels. Ethanol consumption caused a hepatic lipid content of 227 mg/g liver after 6 weeks whereas co-administration of WCE, especially at high dosage, significantly reduced it to 187 mg/g of liver. Analysis of hepatic fatty acids revealed that WCE suppressed conjugation of oleic acid into TG. These results support probable application of WCE as an anti-alcoholic fatty liver agent.     

大豆异黄酮抗家兔动脉粥样硬化作用

研究大豆异黄酮(ISF)对动脉粥样硬化家兔血浆脂蛋白抗脂质过氧化作用的影响。高脂饲料喂养法建立家兔动脉粥样硬化模型,连续给药8周后,处死动物,观察主动脉壁横切面病理变化。分离血浆脂蛋白,观察各血浆脂蛋白过氧化脂质(LPO)含量及低密度脂蛋白(LDL)氧化易感性的变化。结果表明：ISF可减轻高脂饲料诱导的动脉粥样硬化家兔主动脉病理变化;显著降低家兔血浆总胆固醇(TC)和低密度脂蛋白胆固醇(LDL-CH)水平(P＜0.05);显著降低血浆总LPO和脂蛋白LPO含量(P＜0.05);在体外进行氧化修饰时,延长LDL氧化延滞时间。提示,ISF可降低动脉粥样硬化家兔LDL胆固醇水平和脂质过氧化程度,增强LDL抗氧化修饰能力,因此能够起到防治动脉粥样硬化症的积极作用。     

A high-resistance-starch rice diet reduces glycosylated hemoglobin levels and improves the antioxidant status in diabetic rats

Diabetes mellitus is a common problem in developed countries. An improved postprandial hyperglycemic peak is one of the main therapeutic targets in diabetic patients. The Wistar rats with streptozotocin (STZ)-induced diabetes were divided into cornstarch (control) and Japonica rice groups, which were fed 640 g starch/kg diets for 4 weeks. The area (means ± SD) under the glucose curve of cornstarch was 173.8 ± 6.9 and Japonica rice diet was 154.3 ± 8.7 mmol × min/L, and the area (means ± SD) under the insulin curve of cornstarch was 12.9 ± 0.1 and Japonica rice diet was 12.0 ± 0.6 nmol × min/L. The glycosylated hemoglobin levels, serum fructosamine and cholesterol concentrations in diabetic rats fed the Japonica rice diet were significantly lower than the control group (P < 0.05). The decreased malondialdehyde levels and increased superoxide dismutase activity and total radical-trapping antioxidant parameter in plasma were also found in rat fed the Japonica rice diet compared to the control. These results suggested that the diet containing high-resistance-starch Japonica rice might reduce glycosylated hemoglobin levels, serum cholesterol concentrations and raised the antioxidant status in the blood.