Serotonin derivatives, major safflower (Carthamus tinctorius L.) seed antioxidants, inhibit low-density lipoprotein (LDL) oxidation and atherosclerosis in apolipoprotein E-deficient mice

The effects of defatted safflower seed extract and its phenolic constituents, serotonin derivatives, on atherosclerosis were studied. Ethanol-ethyl acetate extract of safflower seeds (SSE) inhibited low-density lipoprotein (LDL) oxidation induced in vitro by an azo-containing free-radical initiator V70 or copper ions. Two serotonin derivatives [N-(p-coumaroyl)serotonin, CS; N-feruloylserotonin, FS] and their glucosides were identified as the major phenolic constituents of the extract. The study with chemically synthesized materials revealed that a majority of the antioxidative activity of SSE was attributable to the aglycones of these two serotonin derivatives. Orally administered CS and FS suppressed CuSO(4)-induced plasma oxidation ex vivo. Long-term (15 week) dietary supplementation of SSE (1.0 wt %/wt) and synthetic serotonin derivatives (0.2-0.4%) significantly reduced the atherosclerotic lesion area in the aortic sinus of apolipoprotein E-deficient mice (29.2-79.7% reduction). The plasma level of both lipid peroxides and anti-oxidized LDL autoantibody titers decreased concomitantly with the reduction of lesion formation. Serotonin derivatives were detected as both intact and conjugated metabolites in the plasma of C57BL/6J mice fed on 1.0% SSE diet. These findings demonstrate that serotonin derivatives of SSE are absorbed into circulation and attenuate atherosclerotic lesion development possibly because of the inhibition of oxidized LDL formation through their strong antioxidative activity.     

Antioxidative functions of natto,a kind of fermented soybeans: effect on LDL oxidation and lipid metabolism in cholesterol-fed rats

Natto water-soluble fractions, low-molecular-weight viscous substance, and soybean water extract, which had an inhibitory effect on the oxidation of low-density lipoproteins (LDL) in vitro, were fed to rats for 3 weeks. These fractions had no influence on the growth of rats, which were fed a basal diet containing 1% cholesterol, but lowered plasma triglyceride and total cholesterol. Inhibition of copper-oxidation of plasma and LDL ex vivo, and a reduction in lipid peroxidation in liver and aorta in vivo, were also observed. The antioxidant enzymes were not induced in rats fed natto fraction diets. These results demonstrate that ingestion of the natto fractions led to inhibition of LDL oxidation, and that the fractions perform direct antioxidant action in the body. It is suggested that natto fractions might help to prevent arteriosclerosis, as they appear to reduce lipid peroxidation and improve lipid metabolism.     

Improving the lipid profile in hypercholesterolemia-induced rabbit by supplementation of germinated brown rice

It is imperative that there be a diet designed specifically to improve lipid profile in order to impede the progress of atherosclerosis. Because rice is a staple food in Asia, it will be chosen as the diet of interest. This study sets out to discover whether consumption of different processed rice diets may result in a change of the lipid profile. The experiment was done on male New Zealand white rabbits after 10 weeks of treatment with diet containing 0.5% cholesterol. The experimental diets include white rice (WR), brown rice (BR), and germinated brown rice (GBR). Among them, rabbits fed a GBR diet demonstrated significantly lower levels of total cholesterol (TC), low-density lipoprotein (LDL), LDL/HDL, and atherogenic index (AI) and a higher level of high-density lipoprotein (HDL). Results from atherosclerotic plaque assessment further support the findings. The level of malondialdehyde (MDA), which acts as an indicator for oxidative stress, was also reduced by GBR diet. The positive change in lipid profile in the rabbits fed GBR appeared to correspond with the higher amounts of γ-oryzanol, tocopherol, and monounsaturated fatty acid (MUFA) content.     

Red wine antioxidants bind to human lipoproteins and protect them from metal ion-dependent and -independent oxidation

Plant-derived polyphenols may exert beneficial effects on atherosclerosis and cardiovascular diseases, in part, because of their antioxidant properties. In this study we compared the effects of unbound (free) and lipoprotein-associated red wine components on in vitro antioxidant protection of human low-density lipoprotein (LDL). Preincubation of LDL (1 mg protein/mL) with 0-2.5% (v/v) red wine for 3 h at 37 degrees C followed by gel filtration to remove unbound red wine components resulted in a dose-dependent, up to 4-fold increase in LDL-associated antioxidant capacity (measured as Trolox equivalents). Similar results were obtained with high-density lipoprotein (HDL) and bovine serum albumin (BSA). Furthermore, LDL was subjected to oxidation by copper and aqueous peroxyl radicals (2,2'-azobis[2-amidinopropane] dihydrochloride, AAPH). Under both types of oxidative stress, LDL-associated and free red wine components significantly decreased oxidation of the lipoprotein's protein moiety (assessed by tryptophan fluorescence) and lipid moiety (assessed by thiobarbituric acid-reactive substances and conjugated dienes). Similar protective effects of red wine components were observed against HDL oxidation. In contrast, red wine exerted a pro-oxidant effect on copper-induced oxidation of BSA tryptophan residues, while protecting them from AAPH-induced oxidation. Ascorbate strongly enhanced the protective effect of red wine against copper-induced LDL oxidation, and had an additive effect against AAPH-induced oxidation. Our data indicate that red wine components bind to LDL and HDL and protect these lipoproteins from metal ion-dependent and -independent protein and lipid oxidation.     

Apple polyphenols and fibers attenuate atherosclerosis in apolipoprotein E-deficient mice

Atherosclerosis, which is closely linked to nutritional habits, is a major cause of mortality in Western countries. Most of the previous investigations carried out on health effects of apples have been focused on their capacity to lower lipid concentration as well as on their antioxidant effects. The aim of the present study was to investigate the antiatherosclerotic effects of apple polyphenols and fibers. A crude apple polyphenol extract and low-viscosity apple fibers isolated from cider apples were administered separately or in association with the diet of apo E-deficient mice. After 4 months of supplementation, lipemia and oxidative stress biomarkers were measured and atheroslerotic lesions assessed by histomorphometry. Total plasmatic cholesterol and triacylgycerol levels were not affected by supplementation, and hepatic cholesterol level was lower in the group supplemented with both fibers and polyphenols. Uric acid concentrations and antioxidant capacity (FRAP) in plasma were reduced in all groups supplemented with polyphenols or fibers. The mean lesion area was reduced by 17, 38, and 38%, respectively, for the polyphenol, fiber, and polyphenol + fiber groups. Apple constituents supplied at nutritional doses therefore limit the development of atherosclerotic lesions in the aorta of apo E-deficient mice. On the basis of the results, we hypothesize that apple fibers and polyphenols may play a role in preventing atherosclerosis disease by decreasing uric acid plasma level.     

Effects of anthocyanins on psychological stress-induced oxidative stress and neurotransmitter status

There is strong evidence that oxidative stress participates in the etiology of neurodegenerative diseases such as Parkinson's, and Alzheimer's diseases. Moreover, emotional stress effects in the central nervous system play a vital role in homeostasis. The protective effect of anthocyanins on the cerebral oxidative stress was studied using the whiskers cut model. In mice, such treatment causes psychological or emotional distress leading to oxidative stress in tissues. To investigate the in vivo antioxidant activity of anthocyanins, an extract of Vaccinium myrtillis L., an anthocyanin mixture, was orally administered (100 mg/kg of body weight.) to mice for 7 days, and then psychological stress was assessed by cutting off their whiskers. Whisker removal increased both protein carbonyl formation and lipid peroxidation in the brain, heart, kidney, and liver. Further, the levels of oxidative markers showed regional differences in the brain. Concomitantly, dopamine neurotransmitter levels were altered in both the midbrain and the brain cortex. Orally administered anthocyanins were also active in the brain, suppressing stress-induced cerebral oxidative stress and dopamine abnormalities in distressed mice. These effects of anthocyanin treatment suggest their possible usefulness for the treatment of cerebral disorders related to oxidative stress.     

Influence on hazelnut oil administration on peroxidation status of erythrocytes and apolipoprotein B 100-containing lipoproteins in rabbits fed on a high cholesterol diet

Hazelnut oil (HO) is rich in monounsaturated fatty acids (MUFA). The effect of a high cholesterol (HC) diet with and without HO on lipids and lipid peroxide levels in plasma, apolipoprotein B 100-containing lipoproteins (VLDL + LDL), and erythrocytes as well as hematological data was investigated in rabbits. A HC diet caused significant increases in lipid peroxide levels in plasma and apo B-containing lipoproteins together with histopathological atherosclerotic findings in aorta. In addition, this diet resulted in hemolytic anemia associated with increased endogenous diene conjugate (DC) levels, but H(2)O(2)-induced malondialdehyde (MDA) levels remained unchanged in erythrocytes. HO supplementation reduced lipid peroxide levels in plasma and apolipoprotein B 100-containing lipoproteins as well as aortic atherosclerotic lesions in rabbits fed an HC diet without any decreasing effect on lipid levels. In addition, HO was found to reduce hemolytic anemia together with significant decreases in DC and H(2)O(2)-induced MDA levels.     

Grape seed proanthocyanidins prevent plasma postprandial oxidative stress in humans

Postprandial hyperlipemia is a well-defined risk factor for atherosclerosis. A reasonable contributing mechanism could involve the postprandial increase of plasma lipid hydroperoxides (LPO) affecting the oxidant/antioxidant balance and increasing the susceptibility of LDL to oxidation. Wine has been shown to prevent both these events. The present study was designed to investigate the effect of supplementing a meal with grape seed proanthocyanidins (the main phenolic antioxidant of red wine) on plasma postprandial oxidative stress. In two different sessions, 8 healthy volunteers consumed the same test meal rich in oxidized and oxidizable lipids without (control) or with 300 mg of a proanthocyanidin-rich grape seeds extract (GSE). Lipid hydroperoxide concentration, antioxidant status, and LDL resistance to oxidative modification were measured in postprandial plasma. The content of LPO in chylomicrons was 1.5-fold higher after the control meal than after the GSE-supplemented meal. Plasma LPO increased only after consumption of the control meal. The plasma antioxidant capacity increased in the postprandial phase only following the GSE supplemented meal. LDL isolated 3 h after the control meal tended to be more susceptible to oxidative modification (but the difference did not reach statistical significance). An opposite trend was observed following the GSE supplemented meal. In conclusion, the supplementation of a meal with GSE minimizes the postprandial oxidative stress by decreasing the oxidants and increasing the antioxidant levels in plasma, and, as a consequence, enhancing the resistance to oxidative modification of LDL.     

Protective effects of bilberry (Vaccinium myrtillus L.) extract on restraint stress-induced liver damage in mice

Our experiments showed that 18 h restraint stress could induce serious liver damage, with an increase in plasma alanine aminotransferase (ALT) level (107.68 +/- 3.19 U/L vs 18.08 +/- 1.46 U/L). Meanwhile, we observed increased malondialdehyde (MDA) levels and lowered oxygen radical absorbance capacity (ORAC) values in plasma and liver of restraint mice compared with starved mice. Bilberry extract (containing 42.04% anthocyanins) was oral administrated to mice at 50, 100, and 200 mg/(kg x day) for five days, which remarkably decreased plasma ALT level to 17.23 +/- 2.49 U/L at the dose of 200 mg/(kg x day) and thus alleviated stress-induced liver damage. In addition, bilberry extracts increased glutathione (GSH) and vitamin C levels and significantly decreased MDA and nitric oxide (NO) levels in the liver tissues. These results suggest that bilberry extract plays an important role in protecting against restraint stress-induced liver damage by both scavenging free radicals activity and lipid peroxidation inhibitory effect. This study showed the beneficial health effects of bilberry extract through its antioxidative action.     

Red mold dioscorea has greater hypolipidemic and antiatherosclerotic effect than traditional red mold rice and unfermented dioscorea in hamsters

Monascus-fermented red mold dioscorea (RMD) was proven to produce higher monacolin K levels than red mold rice (RMR) in our previous study. The goal of this study is to investigate whether the novel RMD had more hypolipidemic and antiatherosclerotic effect than traditional red mold rice. The daily dose of RMR for adults was recommended as 1 g, which corresponded to 96 mg/kg/day for hamsters. Therefore, high cholesterol diet-induced hyperlipidemic hamsters were daily administrated with a 0.5-fold (48 mg/kg/day), a 1-fold (96 mg/kg/day), or a 5-fold dose (480 mg/kg/day) of RMD for 8 weeks. Furthermore, a 1-fold dose of RMR (96 mg/kg/day) and unfermented dioscorea (96 mg/kg/day) were also respectively used to evaluate the effect of hypolipidemic and antiarteriosclerosis. The results indicated that only needing a 0.5-fold dose of RMD was able to significantly lower total cholesterol (by 13.78%, p<0.001), triglyceride (by 38.74%, p<0.01), and low-density lipoprotein cholesterol levels (by 43.11%, p<0.05) as well as maintain a high-density lipoprotein cholesterol level, as compared to the hyperlipidemic group. RMD including a higher monacolin K level and a dioscorea substrate was able to exhibit a more significant difference in the hypolipidemic effect than RMR or unfermented dioscorea. Both RMR and dioscorea exhibited potent in vitro antioxidative ability and in vivo protection against hypolipidemia-induced oxidative stress. Therefore, the antioxidative ability of RMD provided by Monascus metabolites (dimerumic acid, tannin, phenol, etc.) as well as dioscorea was able to perform more antiatherosclerotic effects on increasing total antioxidant status, catalase, and superoxide dismutase activity and repressing lipid peroxidation and atherosclerotic plaque than RMR and dioscorea.     

Pomegranate byproduct administration to apolipoprotein e-deficient mice attenuates atherosclerosis development as a result of decreased macrophage oxidative stress and reduced cellular uptake of oxidized low-density lipoprotein

The effects of a pomegranate byproduct (PBP, which includes the whole pomegranate fruit left after juice preparation) on atherosclerosis development in apolipoprotein E-deficient (E degrees ) mice were studied. Consumption of PBP (17 or 51.5 microg of gallic acid equiv/kg/day) by the mice resulted in a significant reduction in atherosclerotic lesion size by up to 57%. PBP consumption significantly reduced oxidative stress in the mice peritoneal macrophages (MPM): Cellular lipid peroxide content decreased by up to 42%, the reduced glutathione levels increased by up to 53%, and paraoxonase 2 lactonase activity increased by up to 50%, as compared to MPM from E degrees mice that consumed only water. Furthermore, oxidized low-density lipoprotein (Ox-LDL) uptake by the MPM was reduced by up to 19%. Similar results were observed also in vitro. Treatment of J774A.1 macrophages with PBP (10 or 50 micromol/L of total polyphenols) significantly decreased both cellular total peroxide content and Ox-LDL uptake. It was thus concluded that PBP significantly attenuates atherosclerosis development by its antioxidant properties.     

Consumption of a novel dietary formula of plant sterol esters of canola oil fatty acids, in a canola oil matrix containing 1,3-diacylglycerol, reduces oxidative stress in atherosclerotic apolipoprotein E-deficient mice

The antiatherogenic properties of a novel dietary formula (PS-CO) of plant sterol esters of fatty acids, produced by enzymatic interesterification of plant sterols with canola oil (CO), in a CO matrix containing 1,3-diacylglycerol, were evaluated in apolipoprotein E-deficient mice. PS-CO consumption strongly tended to lower total plasma cholesterol levels by 21%, compared to the placebo group. Blood triglycerides were reduced by 38% and 36% compared to CO and placebo-fed mice, respectively. Serum lipid peroxide levels were lowered following PS-CO administration by 62% and 63%, compared to CO and placebo administration, respectively. Unlike CO supplementation, PS-CO consumption preserved serum paraoxonase (PON1) activity. Mouse peritoneal macrophages from PS-CO-fed mice exhibited reduced cellular uptake of oxidized-LDL compared to those from placebo-fed mice and demonstrated a tendency toward a decreased capability to release superoxide anions. These findings indicate that PS-CO supplementation is beneficial in reducing serum lipid levels, and serum and macrophage oxidative stress, thus contributing to the reduction in atherogenic risk factors.     

Protein-lipid interactions during liposome oxidation with added anthocyanin and other phenolic compounds

Oxidation of bovine serum albumin, casein, and lactalbumin and the effect of different procyanidins, anthocyanins, and their aglycons (10 and 20 microM) on lactalbumin oxidation were investigated in a liposome system. Samples were incubated in the dark at 37 degrees C with copper, and the extent of oxidation was measured by determining the loss of tryptophan fluorescence and the formation of protein carbonyls, conjugated diene hydroperoxides, and hexanal. The correlation between different protein and lipid oxidation measurements was good and statistically significant. Casein was the most stable protein in the liposome model, and it was also the best inhibitor of liposome oxidation. All tested anthocyanins and other phenolic compounds inhibited both lipid and protein oxidation. There were no systematic differences with anthocyanins and their aglycons in relation to the concentrations used or glycosylation with either glucose or rutinose. Procyanidins B1 and B2 and ellagic acid were potentially better antioxidants than anthocyanins due to their several hydroxyl groups as measured by both protein and lipid oxidation. In conclusion, oxidative deterioration of liposomes due to protein-lipid interaction is inhibited by anthocyanins, procyanidins, and ellagitannin present, for example, in berries.     

Supplementation of plasma with olive oil phenols and extracts: influence on LDL oxidation

Phenols present in olive oil may contribute to the health effects of the Mediterranean lifestyle. Olive oil antioxidants increase the resistance of low-density lipoproteins (LDL) against oxidation in vitro, but human intervention studies have failed to demonstrate similar consistent effects. To better mimic the in vivo situation, plasma was incubated with either individual olive oil phenols or olive oil extracts with different phenolic compositions, and LDL was subsequently isolated and challenged for its resistance to oxidation. The results show that the ortho-dihydroxy phenols (hydroxytyrosol and oleuropein-aglycone) are more efficient than their mono-hydroxy counterparts (tyrosol and ligstroside-aglycone) in increasing the resistance of LDL to oxidation. However, the concentration of antioxidants required to inhibit LDL oxidation when added to whole plasma was substantially higher as compared to previous data where antioxidants are directly added to isolated LDL. In conclusion, this study supports the hypothesis that extra virgin olive oil phenols protect LDL in plasma against oxidation. The explanation that in vitro studies show protective effects in contrast to the lack of effect in the majority of human studies may be that the dose of the phenols and thus their plasma concentration in humans was too low to influence ex vivo LDL oxidizability. Further studies are required to gain a better understanding of the potential health benefits that extra virgin olive oil may provide.     

Nutritional and biological properties of extra virgin olive oil

The nutritional benefits generally recognized for the consumption of extra virgin olive oil (EVOO) are based on a large number of dietary trials of several international populations and intervention studies. Unfortunately, many authors in this field used questionable analytical methods and commercial kits that were not validated scientifically to evaluate the complex bioactive constituents of EVOO and lipid oxidation and decomposition products. Many questionable antiradical methods were commonly used to evaluate natural polyphenolic antioxidants, including an indirect method to determine low-density lipoprotein (LDL) cholesterol. Extensive differences were observed in experimental design, diet control, populations of different ages and problems of compliance intervention, and questionable biomarkers of oxidative stress. Analyses in many nutritional studies were limited by the use of one-dimensional methods to evaluate multifunctional complex bioactive compounds and plasma lipid profiles by the common applications of commercial kits. Although EVOO contains polyphenolic compounds that exhibit significant in vitro antioxidant activity, much more research is needed to understand the absorption and in vivo activity. Many claims of in vivo human beneficial effects by the consumption of EVOO may be overstated. No distinctions were apparently made between in vivo studies based on general health effects in large populations of human subjects and smaller scale well-controlled feeding trials using either pure or mixtures of known phenolic constituents of EVOO. More reliable protocols and testing methods are needed to better validate the complex nutritional properties of EVOO.     

Juice and phenolic fractions of the berry Aristotelia chilensis inhibit LDL oxidation in vitro and protect human endothelial cells against oxidative stress

Oxidative modification of low-density lipoprotein (LDL) particles is a key event in the development of atherosclerosis. Oxidized LDL induces oxidative stress and modifies gene expression in endothelial cells. Berries constitute a rich dietary source of phenolic antioxidants. We found that the endemic Chilean berry Aristotelia chilensis (ach) has higher phenol content and scores better for total radical-trapping potential and total antioxidant reactivity in in vitro antioxidant capacity tests, when compared to different commercial berries. The juice of ach is also effective in inhibiting copper-induced LDL oxidation. In human endothelial cell cultures, the addition of ach juice significantly protects from hydrogen peroxide-induced intracellular oxidative stress and is dose-dependent. The aqueous, anthocyanin-rich fraction of ach juice accounts for most of ach's antioxidant properties. These results show that ach is a rich source of phenolics with high antioxidant capacity and suggest that it may have antiatherogenic properties.     

Antioxidative and antiglycative effects of six organosulfur compounds in low-density lipoprotein and plasma

Low-density lipoprotein (LDL) and plasma were isolated from patients with non-insulin-dependent diabetes. The protective effects of six organosulfur compounds (DAS, diallyl sulfide; DADS, diallyl disulfide; SAC, S-allylcysteine; SEC, S-ethylcysteine; SMC, S-methylcysteine; SPC, S-propylcysteine) against further oxidation and glycation in these already partially oxidized and glycated samples were studied. DAS and DADS showed significantly greater oxidative-delaying effects than four cysteine-containing compounds in both partially oxidized LDL and plasma samples (P < 0.05). However, cysteine-containing agents were superior to DAS and DADS in delaying glycative deterioration in already partially glycated LDL (P < 0.05). The observed delays of oxidative and glycative effects from each agent were significantly concentration-dependent (P < 0.05). Furthermore, six organosulfur agents significantly decreased the loss of catalase and glutathione peroxidase activities in plasma and increased alpha-tocopherol retention in LDL and plasma (P < 0.05). These results suggested that the use of these organosulfur agents derived from garlic at these concentrations could protect partially oxidized and glycated LDL or plasma against further oxidative and glycative deterioration, which might benefit patients with diabetic-related vascular diseases.     

Significance of preslaughter stress and different tissue PUFA levels on the oxidative status and stability of porcine muscle and meat

Polyunsaturated fatty acids (PUFAs) and exercise-induced stress are known to increase the oxidative susceptibility of lipids in muscle tissue. In contrast, antioxidative enzymes, e.g., catalase, superoxide dismutase, and glutathione peroxidase, are known to help sustain the delicate oxidative balance in biological tissue upon the application of stressors. The present study investigates the combined effect of different diet-induced muscle PUFA contents and preslaughter stress on the activity of antioxidative muscle enzymes and the oxidative stability of cooked meat. An increased content of unsaturated fatty acids in the tissue led to a decreased activity of lactate dehydrogenase in the plasma, indicating increased cell integrity. Catalase activity in the muscle tissue increased with increasing PUFA levels. However, this upregulation in antioxidative status of the muscle could not counteract the subsequent development of accelerated lipid oxidation in cooked meat as measured in terms of thiobarbituric acid reactive substances. Moreover, preslaughter stress induced increasing oxidative changes with elevated PUFA levels in the muscle tissue.     

Effects of proanthocyanidin preparations on hyperlipidemia and other biomarkers in mouse model of type 2 diabetes

The protective effect of proanthocyanidins from persimmon peel, using both oligomers and polymers, was investigated in a db/db type 2 diabetes model. Male db/db mice were divided into three groups: control (vehicle), polymer-, or oligomer- (10 mg/(kg body weight x day x p.o.)) administered mice. Age-matched nondiabetic m/m mice were used as a normal group. The administration of proanthocyanidins reduced hyperglycemia in db/db mice through a decline in the serum level of glucose and glycosylated protein. In addition, it had a strong effect on hyperlipidemia through lowering levels of triglyceride, total cholesterol, and nonesterified fatty acids. The protective effect against hyperglycemia and hyperlipidemia was greater in the groups administered the oligomeric rather than polymeric form. The increased oxidative stress in db/db mice was attenuated by the administration of oligomers through inhibiting the generation of reactive oxygen species and lipid peroxidation and elevating the reduced glutathione/oxidized glutathione ratio. On the other hand, polymers did not show such an effect. Moreover, expressions in the liver of sterol regulatory element binding protein (SREBP)-1 and SREBP-2 were downregulated by the administration of proanthocyanidins, especially the oligomeric form. Oligomers caused a slight elevation in the expression of peroxisome proliferator-activated receptors alpha. Furthermore, oligomeric proanthocyanidin regulated the expression of nuclear factor kappaB in db/db type 2 diabetes via the activation of inhibitor protein kappaB-alpha. It also attenuated the protein expressions of cyclooxygenase-2 and inducible nitric oxide synthase. This suggests that oligomers would act as a regulator in inflammatory reactions associated with oxidative stress in type 2 diabetes. The present study results suggest that proanthocyanidin administration, especially the oligomeric form, may improve oxidative stress via the regulation of hyperlipidemia than hyperglycemia in type 2 diabetes.     

Ameliorative influence of sesame lignans on lipid profile and lipid peroxidation in induced diabetic rats

Sesame lignans are working as antioxidants in various physiological functions. In the present study, the antioxidative effect of sesame lignans is examined in chemically induced diabetes mellitus (DM) in rats against lipid profile and lipid peroxidations. DM was induced in four groups of rats by injection of alloxan. The control groups (non-diabetic and diabetic) received a diet containing sunflower oil while the rest of the three experimental diabetic groups received a diet containing 0.25% alpha-tocopherol (D-Toc), 0.5% sesame lignan (D-SL), and 0.25% alpha-tocopherol+0.25% sesame lignan (D-Toc-SL) in sunflower oil for 4 weeks. Lipid profile and lipid peroxidations of plasma, erythrocyte membrane (EM), and liver tissues were measured. The total cholesterol, non-HDL cholesterol, plasma lipid peroxidation, and also LDL-peroxidation decreased, and HDL cholesterol increased significantly (P<0.05) in all the experimental groups as compared to the control diabetic sunflower oil group. The triacylglycerol (TAG) level in plasma decreased significantly in the D-SL and D-Toc-SL groups as compared to control diabetic group. Significant decrease in TAG level was observed in the D-SL group as compared to the D-Toc group. LDL peroxidation also decreased significantly in the D-Toc-SL group as compared to the D-Toc group. EM lipid peroxidation and liver lipid peroxidation decreased significantly in the D-Toc, D-SL, and D-Toc-SL groups as compared to the control diabetic group. Liver TAG level decreased more significantly in the D-SL and D-Toc-SL groups than in the control diabetic group. So, sesame lignans at 0.5% level and sesame lignan + alpha-tocopherol significantly ameliorate the alteration in lipid profile and the adverse free radical generative influence of DM induced by alloxan.