Dietary flax seed in prevention of hypercholesterolemic atherosclerosis

Caiman's fat enriched with n-3 fatty acids: potential food supplement

Broad-snouted caiman (Caiman latirostris) products (meat, fat and oil) are currently beginning to be valued as a food of special interest due to its high content of n-3 fatty acids. Thus, the objective of this study was to characterize the fats of caiman fed with diets enriched with flaxseeds (Linus usitatissimun) rich in n-3 fatty acids, lignans and antioxidants. Caimans were fed six days a week with: a control diet (C), and a diet enriched with ground flaxseed = 90% C + 10% flaxseed ground (FS), during 30 (FS30) and 60 (FS60) days. Animals fed the flaxseed-enriched diets increased linolenic acid content and reduced the n-6/n-3 ratio of fats relative to controls, and this improvement increased over time. The proportion of eicosapentaenoic acid also increased, but there was no difference at the time the enriched diets were offered. Caiman fat of the FS30 and FS60, showed a decrease in lipoperoxidation (24% and 40%) and reactive oxygen species (44% and 76%) accompanied by an increase in antioxidant systems. Consumption of a flax-enriched diet by caimans increases the content of essential fatty acids and improves the lipoperoxidative status of fat. This provides an enriched fat with potential for the development products for human consumption.

Health benefits of flaxseed and its peptides (linusorbs)

Flaxseed (Linum usitatissimum L.) has been associated with numerous health benefits. The flax plant synthesizes an array of biologically active compounds including peptides or linusorbs (LOs, a.k.a., cyclolinopeptides), lignans, soluble dietary fiber and omega-3 fatty acids. The LOs arise from post-translational modification of four or more ribosome-derived precursors. These compounds exhibit an array of biological activities, including suppression of T-cell proliferation, excessive inflammation, and osteoclast replication as well as induction of apoptosis in some cancer cell lines. The mechanisms of LO action are only now being elucidated but these compounds might interact with other active compounds in flaxseed and contribute to biological activity attributed to other flax compounds. This review focuses on both the biological interaction of LOs with proteins and other molecules and comprehensive knowledge of LO pharmacological and biological properties. The physicochemical and nutraceutical properties of LOs, as well as the biological effects of certain LOs, and their underlying mechanisms of action, are reviewed. Finally, strategies for producing LOs by either peptide synthesis or recombinant organisms are presented. This review will be the first to describe LOs as a versatile scaffold for the action of compounds to deliver physiochemically/biologically active molecules for developing novel nutraceuticals and pharmaceuticals.

Availability of bioactive flax lignan from foods and supplements

Hyperlipidemia, high levels of blood lipids including cholesterol and triglycerides, is a major risk factor for cardiovascular disease. Traditional treatments of hyperlipidemia often include lifestyle changes and pharmacotherapy. Recently, flaxseed has been approved as a nutrient that lowers blood lipids. Several metabolites of flaxseed lignan secoisolariciresinol diglucoside (SDG), have been identified that reduce blood lipids. SDG is present in flaxseed hull as an ester-linked copolymer with 3-hydroxy-3-methylglutaric acid (HMGA). However, purification processes involved in hydrolysis of the copolymer and enriching SDG are often expensive. The natural copolymer of SDG with HMGA (SDG polymer) is a source of bioactive compounds useful in prophylaxis of hypercholesterolemia. After consumption of the lignan copolymer, SDG and HMGA are released in the stomach and small intestines. SDG is metabolized to secoisolariciresinol, enterolactone and enterodiol, the bioactive forms of mammalian lignans. These metabolites are then distributed throughout the body where they accumulate in the liver, kidney, skin, other tissues, and organs. Successively, these metabolites reduce blood lipids including cholesterol, triglycerides, low density lipoprotein cholesterol, and lipid peroxidation products. In this review, the metabolism and efficacies of flaxseed-derived enriched SDG and SDG polymer will be discussed.

Hypocholesterolemic Efficacy of Secoisolariciresinol Diglucoside and Its Polymer in Rat

Hypercholesterolemia is a risk factor for cardiovascular disease. Conventional treatment methods include lifestyle changes and pharmaceutical interventions, but recently Health Canada approved a health claim for whole ground flaxseed as an alternative treatment for hypercholesterolemia. The literature suggests flaxseed lignans are responsible for the cholesterol-reducing effects of flaxseed. In this study, 96.1% secoisolariciresinol diglucoside (SDG) and a 50% SDG enriched polymer (SDG polymer) were investigated as treatments for hypercholesterolemia in rats. Wistar female rats were fed a 1% high-cholesterol diet for a one-week acclimatization prior to a 23-day intervention with enriched SDG or SDG polymer. A reduction in body weight normalized liver weight was observed in rats treated with enriched SDG when compared to the controls. Both enriched SDG (96.1%) and SDG polymer reduced serum triacylglycerol (19% and 15%, respectively) and increased high-density lipoprotein cholesterol (15% and 24%, respectively). Histopathologic analyses revealed lipid-lowering effects of either enriched SDG or SDG polymer along with lower steatosis scores and nonalcoholic fatty liver disease activity. Furthermore, the lack of statistical significance between SDG and SDG polymer treatment groups suggests that SDG polymer may be a potential alternative to enriched SDG for hypercholesterolemia with similar efficacy but lower cost.

Atherosclerosis Development and Aortic Contractility in Hypercholesterolemic Rabbits Supplemented with Two Different Flaxseed Varieties

Alpha-linolenic acid (ALA) is widely regarded as the main beneficial component of flax for the prevention of cardiovascular disease. We evaluated the effect of the transgenic flaxseed W86-which is rich in ALA-on the lipid profile, atherosclerosis progression, and vascular reactivity in hypercholesterolemic rabbits compared to the parental cultivar Linola with a very low ALA content. Rabbits were fed a basal diet (control) or a basal diet supplemented with 1% cholesterol, 1% cholesterol and 10% flaxseed W86, or 1% cholesterol and 10% Linola flaxseed. A high-cholesterol diet resulted in an elevated plasma cholesterol and triglyceride levels compared to the control animals. Aortic sections from rabbits fed Linola had lower deposits of foamy cells than those from rabbits fed W86. A potassium-induced and phenylephrine-induced contractile response was enhanced by a high-cholesterol diet and not influenced by the W86 or Linola flaxseed. Pretreatment of the aortic rings with nitro-L-arginine methyl ester resulted in a concentration-dependent tendency to increase the reaction amplitude in the control and high-cholesterol diet groups but not the flaxseed groups. Linola flaxseed with a low ALA content more effectively reduced the atherosclerosis progression compared with the W86 flaxseed with a high concentration of stable ALA. Aorta contractility studies suggested that flaxseed ameliorated an increased contractility in hypercholesterolemia but had little or no impact on NO synthesis in the vascular wall.

Flaxseed and Its Components in Treatment of Hyperlipidemia and Cardiovascular Disease

This paper describes the effects of flaxseed and its components (flax oil, secoisolariciresinoldiglucoside[SDG], flax lignan complex [FLC], and flax fibers] on serum lipids (total cholesterol [TC], low-density lipoprotein-cholesterol [LDL-C], high-density lipoprotein cholesterol [HDL-C], and triglycerides [TG]) in animals and humans. Ordinary flaxseed reduces TG, TC, LDL-C, and TC/HDL-C levels in a dose-dependent manner in animals. In humans, it reduces serum lipids in hypercholesterolemicpatients but has no effects in normocholesterolemicpatients. Flax oil has variable effects on serum lipids in normo- and hypercholesterolemic animals. Flax oil treatment, with a dosage containing greater than 25 g/day of α-linolenic acid, reduces serum lipids in humans. Although FLC reduces serum lipids and raises serum HDL-C in animals, its effects on serum lipids in humans are small and variable. Flax fibers exert small effects on serum lipids in humans. Crop Development Centre (CDC)-flaxseed, which contains low concentrations of α-linolenic acid, has significant lipid lowering effects in animals. Pure SDG has potent hypolipidemic effects and raises HDL-C. In conclusion, flaxseed and pure SDG have significant lipid-lowering effects in animals and humans, while other components of flaxseed have small and variable effects.

A small-scale fractionation pipeline for rapid analysis of seed mucilage characteristics

BACKGROUND

Myxospermy is a process by which the external surfaces of seeds of many plant species produce mucilage-a polysaccharide-rich gel with numerous fundamental research and industrial applications. Due to its functional properties the mucilage can be difficult to remove from the seed and established methods for mucilage extraction are often incomplete, time-consuming and unnecessarily wasteful of precious seed stocks.

RESULTS

Here we tested the efficacy of several established protocols for seed mucilage extraction and then downsized and adapted the most effective elements into a rapid, small-scale extraction and analysis pipeline. Within 4 h, three chemically- and functionally-distinct mucilage fractions were obtained from myxospermous seeds. These fractions were used to study natural variation and demonstrate structure-function links, to screen for known mucilage quality markers in a field trial, and to identify research and industry-relevant lines from a large mutant population.

CONCLUSION

The use of this pipeline allows rapid analysis of mucilage characteristics from diverse myxospermous germplasm which can contribute to fundamental research into mucilage production and properties, quality testing for industrial manufacturing, and progressing breeding efforts in myxospermous crops.

Flaxseed Lignans as Important Dietary Polyphenols for Cancer Prevention and Treatment: Chemistry, Pharmacokinetics, and Molecular Targets

Cancer causes considerable morbidity and mortality across the world. Socioeconomic, environmental, and lifestyle factors contribute to the increasing cancer prevalence, bespeaking a need for effective prevention and treatment strategies. Phytochemicals like plant polyphenols are generally considered to have anticancer, anti-inflammatory, antiviral, antimicrobial, and immunomodulatory effects, which explain their promotion for human health. The past several decades have contributed to a growing evidence base in the literature that demonstrate ability of polyphenols to modulate multiple targets of carcinogenesis linking models of cancer characteristics (i.e., hallmarks and nutraceutical-based targeting of cancer) via direct or indirect interaction or modulation of cellular and molecular targets. This evidence is particularly relevant for the lignans, an ubiquitous, important class of dietary polyphenols present in high levels in food sources such as flaxseed. Literature evidence on lignans suggests potential benefit in cancer prevention and treatment. This review summarizes the relevant chemical and pharmacokinetic properties of dietary polyphenols and specifically focuses on the biological targets of flaxseed lignans. The consolidation of the considerable body of data on the diverse targets of the lignans will aid continued research into their potential for use in combination with other cancer chemotherapies, utilizing flaxseed lignan-enriched natural products.

The effects of seed from Linum usitatissimum cultivar with increased phenylpropanoid compounds and hydrolysable tannin in a high cholesterol-fed rabbit

Background

Dietary fat is considered one of the most important factors associated with blood lipid metabolism and plays a significant role in the cause and prevention of atherosclerosis that has been widely accepted as an inflammatory disease of the vascular system. The aim of the present study was to evaluate the effect of genetically modified flaxseed (W86) rich in phenylpropanoid compounds and hydrolysable tannin in high cholesterol-induced atherosclerosis rabbit models compared to parental cultivar Linola.

Methods

Twenty-Eight White New Zealand white rabbits aged 6 months were randomly divided into four groups, control group, high cholesterol group (10 g/kg), Linola flaxseed group (100 g/kg) and W86 flaxseed group (100 g/kg). The rabbits were fed a normal diet or a high cholesterol diet for 10 weeks. Levels of blood lipids, hematological values, total antioxidative status and superoxide dismutase activity in serum were determined. Moreover, body weight and feed intake were measured after sixth and tenth weeks. After each stage of the experiment atherogenic indexes (non-HDL-C/HDL-C, LDL-C/HDL-C, and atherogenic index of plasma) was calculated.

Results

The intake of a dyslipidaemic diet negatively influenced lipid profile in rabbits at the 10 weeks of feeding. W86 flaxseed significantly decreased total cholesterol, LDL-C, VLDL-C and TG serum levels in cholesterolemic rabbits compared with parental Linola after 10 weeks. Atherogenic indexes decreased over time with a significant difference between the diets and they were the best for W86 flaxseed. Similarly, the experimental addition of W86 significantly decreased atherogenic predictors such as heterophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and the mean platelet volume-to-lymphocyte ratio. In rabbits, W86 flaxseed increased the activity of superoxide dismutase and total antioxidative status compared to Linola.

Conclusions

Results of the presented study suggest that the addition of W86 flaxseed alleviate serum lipid changes in high cholesterolemic diet-administered rabbits. W86 flaxseed significantly reduced atherogenic indexes, as compared with the Linola and indicate that W86 flaxseed more effectively red CVD risk factors during hypercholesterolemia. Moreover, the presented result suggested that W86 flaxseed can be a part of a heart-healthy and antiatherogenic diet for the human.

Electronic supplementary material

The online version of this article (10.1186/s12944-018-0726-4) contains supplementary material, which is available to authorized users.

Flaxseed: its bioactive components and their cardiovascular benefits

Cardiovascular disease remains the leading cause of mortality and morbidity worldwide. The inclusion of functional foods and natural health products in the diet are gaining increasing recognition as integral components of lifestyle changes in the fight against cardiovascular disease. Several preclinical and clinical studies have shown the beneficial cardiovascular effects of dietary supplementation with flaxseed. The cardiovascular effects of dietary flaxseed have included an antihypertensive action, antiatherogenic effects, a lowering of cholesterol, an anti-inflammatory action, and an inhibition of arrhythmias. Its enrichment in the ω-3 fatty acid α-linolenic acid and the antioxidant lignan secoisolariciresinol diglucoside as well as its high fiber content have been implicated primarily in these beneficial cardiovascular actions. Although not as well recognized, flaxseed is also composed of other potential bioactive compounds such as proteins, cyclolinopeptides, and cyanogenic glycosides, which may also produce biological actions. These compounds could also be responsible for the cardiovascular effects of flaxseed. This article will not only summarize the cardiovascular effects of dietary supplementation with flaxseed but also review its bioactive compounds in terms of their properties, biological effects, and proposed mechanisms of action. It will also discuss promising research directions for the future to identify additional health-related benefits of dietary flaxseed.

Effects of Flaxseed Oil on Serum Lipids and Atherosclerosis in Hypercholesterolemic Rabbits

Objective: Flaxseed oil has very high content of ox-linolenic acid (C18:3n-3, omega-3 [n-3] fatty acid). Based on the usefulness of n-3 fatty acid in fish oil against cardiovascular diseases, flaxseed oil is marketed as a health food. The n-3 fatty acid in flaxseed oil is different than that of fish oil. Indirect evidence suggests that the omega-3 fatty acid in flaxseed oil is not effective in lowering serum lipids and hypercholesterolemic atherosclerosis. The effects of flaxseed oil on serum lipids and hypercholesterolemic atherosclerosis are not known. An investigation, therefore, was made of flaxseed oil on high-cholesterol diet-induced atherosclerosis, serum lipids (triglycerides, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, risk ratio of total cholesterol to high-density lipoprotein cholesterol), serum and aortic malondialdehyde, an index of levels of reactive oxygen species, aortic chemiluminescence (a measure of antioxidant reserve), and reactive oxygen species-producing activity of white blood cell chemiluminescence in rabbits.

Methods: The rabbits were assigned to four groups: Group I, regular diet (control); Group II, 5% flaxseed oil in regular diet; Group III, 0.5% cholesterol diet; Group IV, diet containing 0.5% cholesterol and 5% flaxseed oil. Blood samples were collected before and after 4 and 8 weeks of experimental diets for measurement of serum lipids, serum malondialdehyde, and white blood cell chemiluminescence. At the end of 8 weeks of the experimental diet, aortas were removed for measurement of atherosclerotic plaques, aortic malondialdehyde, and antioxidant reserve.

Results: Serum total cholesterol, triglycerides, and low-density and high-density lipoprotein cholesterol, and risk ratio of total cholesterol to high-density lipoprotein cholesterol, were elevated to a similar extent in Groups III and IV compared to Groups I and II. The extent of atherosclerosis in Groups III and IV was similar (56.74% ± 11.14% vs 58.01% ± 10.95%). Groups III and IV both had similar increases in serum and aortic malondialdehyde and antioxidant reserve. Reactive oxygen species-producing activity of white blood cells increased in Group III, and flaxseed oil prevented the cholesterol-induced increase in white blood cell chemiluminescence in Group IV.

Conclusion: These results suggest that flaxseed oil does not produce an alteration in serum lipids or in the extent of hypercholesterolemic atherosclerosis; however, it decreases white blood cell chemiluminescence. The ineffectiveness of flaxseed oil was associated with its ineffectiveness in altering the levels of oxidative stress.

C-Reactive Protein Increases Oxygen Radical Generation by Neutrophils

C-reactive protein (CRP) has been suggested to play a role in the pathogenesis of atherosclerosis. Neutrophil respiratory burst and levels of CRP are increased during infection. The increase in the neutrophil respiratory burst may be due to factors that are elevated in infection, such as cytokines, tumor necrosis factor, platelet-activating factor, and CRP. The direct effect of CRP on the release of oxygen radicals by neutrophils is not known. This investigation was made to determine if CRP affects the generation of oxygen radicals by neutrophils and if this effect is blocked by antioxidants. The effect of various concentrations (1 to 200 µg/mL blood) of CRP on the generation of oxygen radicals by neutrophils was measured as luminol-dependent chemiluminescence (chemiluminescent activity) on a luminometer (Auto Lumat LB953, EG & G Berthold, Gaithersburg, MD). The unit of chemiluminescent activity is the relative light unit and was expressed as relative light unit/white blood cell (RLU/WBC). Chemiluminescent activity of blood without CRP was slightly higher than that of buffer with or without CRP. CRP markedly increased the chemiluminescent activity of blood. There was no significant change in the chemiluminescent activity of WBCs with 1 µg/mL of CRP. The chemiluminescent activity increased significantly with higher concentrations of CRP. The percent increases in the chemiluminescent activity with 2, 5, 10, 25, 50, 100 and 200 µg/mL of CRP were 45%, 72%, 50%, 70%, 52%, 67%, and 68% respectively. Antioxidants (superoxide dismutase, catalase, and dimethylthiourea) blocked CRP-induced oxygen radicals by WBCs. These results suggest that CRP increases the generation of oxygen radicals from the WBCs. CRP-induced atherosclerosis may be mediated through generation of oxygen radicals by neutrophils.

A Study on Regression of Hypercholesterolemic Atherosclerosis in Rabbits by Flax Lignan Complex

Flax lignan complex (FLC) isolated from flaxseed suppresses the development of hypercholesterolemic atherosclerosis. The objectives of this study were to investigate if FLC produces regression of atherosclerosis and if regression is associated with reductions in serum lipids and oxidative stress. The studies were conducted in 4 groups of rabbits: group I, control diet (2 months); group II, 0.25% cholesterol diet (2 months); group III, 0.25% cholesterol diet (2 months) followed by regular diet (4 months); and group IV, 0.25% cholesterol diet (2 months) followed by regular diet and FLC (4 months). Serum lipids and oxidative stress parameters were measured before and at various intervals thereafter on their respective diets. The aortas were removed at the end of the protocol for assessment of atherosclerotic plaques and oxidative parameters. Atherosclerosis in group II was associated with hyperlipidemia and increased oxidative stress. Atherosclerotic changes were accelerated in group III, and this was associated with reductions in serum lipids and oxidative stress. Atherosclerotic lesions in group IV were similar to group II, but significantly smaller than those in group III, and were associated with reductions in serum lipids and oxidative stress similar to that in group III. These results indicate that FLC does not produce regression but prevents the acceleration of atherosclerosis due to the removal of cholesterol in the diet. These effects of FLC are not associated with reductions in serum lipids and oxidative stress.

Effect of Flaxseed Consumption on Blood Pressure, Serum Lipids, Hemopoietic System and Liver and Kidney Enzymes in Healthy Humans

Background: Effects of flaxseed on serum lipids have been studied in humans, but the results are variable. Flaxseed is ineffective in lowering blood pressure in rats. Its effect on blood pressure in humans is not known. It is also not known if long-term use of flaxseed in humans has deleterious effects on the hemopoietic system, serum glucose, and renal and kidney function. We investigated the effect of short-term use of flaxseed in humans on arterial pressure and serum lipids (triglycerides, total cholesterol; high-, low-, and very-low-densitylipoprotein cholesterol [HDL-C, LDL-C, VLDL-C], hemopoietic system (red blood cells, neutrophils, hemoglobin) and the various biochemical parameters, such as serum protein, albumin, total bilirubin, aspartate aminotransferase, alkaline phosphatase, creatinine, urea, related to hepatic and renal function, and serum glucose.

Methods: Fifteen healthy men, aged 22 to 47 years, consumed three muffins daily containing 32.7 g of total flaxseed for 4 weeks, in addition to their normal daily diet. Blood pressure and blood samples for various biochemical measurements were collected before and after 4 weeks of flaxseed diet.

Results: Blood pressures, heart rate, hemoglobin, and counts of red blood cells, white blood cells, and neutrophils remained unaltered after flaxseed diet. Serum total cholesterol, HDLC, LDL-C, and VLDL-C remained unchanged, but serum triglycerides levels were elevated. Serum total bilirubin, aspartate aminotransferase, alkaline phosphatase, protein, albumin, glucose, and urea remained unaltered, but serum levels of creatinine decreased.

Conclusion: These results suggest that 4 weeks use of flaxseed does not have deleterious effects on the hemopoietic system or renal and hepatic function and does not lower blood pressure and serum lipids. However, the level of serum triglyceride level was elevated.

Effect of water stress on growth of three linseed (Linum usitatissimum L.) varieties

Linseed (Linum usitatissimum L.) is an annual oil crop that accounts for approximately 1 % of the world’s oilseed supplies. It produces seeds that are rich in the health-promoting ω-3 fatty acid, α-linolenic. In Kenya, linseed is grown in the Rift Valley and Western regions, places which often experience drought. This study was aimed at evaluating the effect of water stress on growth of three linseed cultivars and to establish the extent of drought tolerance in the three cultivars. A greenhouse pot experiment in a completely randomized design was conducted at Jomo Kenyatta University of Agriculture and Technology, Kenya. The pots were well watered until the fourth week when watering was completely withheld to a half of the pots (stressed) while the other half (well watered control) was maintained at 90 % field capacity. Destructive harvesting was done when the stressed pots were at 90, 70, 60, 50, 40 % field capacities and at permanent wilting point. The experiment was replicated thrice and was repeated twice (February–May and August–November 2014). There were no significant differences in production of leaves, plant height, number of tillers and biomass between the three varieties in both seasons. Subjecting the linseed varieties to permanent wilting resulted in reduced production of leaves, growth in height, production of tillers and dry weight by 20–40 %. Decline in all growth parameters begun when 30–80 % of available soil water had been used up. There existed linear relationships between the various evaluated growth parameters. These relationships were not influenced either by the water status of soil or the varieties. Relative water content for the three linseed varieties declined after 25–67 % of available soil water had been used up.

Thidiazuron-enhanced biosynthesis and antimicrobial efficacy of silver nanoparticles via improving phytochemical reducing potential in callus culture of Linum usitatissimum L

Green synthesis of silver nanoparticles (AgNPs) by using plants is an emerging class of nanobiotechnology. It revolutionizes all domains of medical sciences by synthesizing chemical-free AgNPs for various biomedical applications. In this report, AgNPs were successfully synthesized by using whole plant extract (WPE) and thidiazuron-induced callus extract (CE) of Linum usitatissimum. The phytochemical analysis revealed that the total phenolic and flavonoid contents were higher in CE than that in WPE. Ultraviolet-visible spectroscopy of synthesized AgNPs showed a characteristic surface plasmon band in the range of 410–426 nm. Bioreduction of CE-mediated AgNPs was completed in a shorter time than that of WPE-mediated AgNPs. Scanning electron microscopy showed that both types of synthesized AgNPs were spherical in shape, but CE-mediated AgNPs were smaller in size (19–24 nm) and more scattered in distribution than that of WPE-mediated AgNPs (49–54 nm). X-ray diffraction analysis confirmed crystalline nature (face-centered cubic) of both types of AgNPs. Fourier-transform infrared spectroscopy revealed that the polyphenols and flavonoids were mainly responsible for reduction and capping of synthesized AgNPs. Energy dispersive X-ray analysis further confirmed the successful synthesis of AgNPs. Moreover, the synthesized AgNPs were found to be stable over months with no change in the surface plasmon bands. More importantly, CE-mediated AgNPs displayed significantly higher bactericidal activity against multiple drug-resistant human pathogens than WPE-mediated AgNPs. The present work highlighted the potent role of thidiazuron in in vitro-derived cultures for enhanced biosynthesis of chemical-free AgNPs, which can be used as nanomedicines in many biomedical applications.

Atherosclerosis and the Hypercholesterolemic AGE-RAGE Axis

Background Interaction of advanced glycation end products (AGE) with the receptor for advanced glycation end products (RAGE) has been implicated in the pathogenesis of atherosclerosis. Soluble receptors for advanced glycation end products (sRAGE) act as a decoy for AGE by competing with RAGE and suppressing developing atherosclerosis. Hypercholesterolemia and the oxidative stress are known factors involved in atherosclerosis. High-density lipoprotein cholesterol (HDL-C) is known to exert a protective effect against the development of atherosclerosis. We hypothesize that hypercholesterolemia-induced atherosclerosis may be mediated through the AGE-RAGE axis. Objectives Two objectives to be determined are: (1) if hypercholesterolemia is positively correlated with serum AGE, AGE/sRAGE, and malondialdehyde (MDA: a marker for oxidative stress) and (2) if the protective effect of HDL-C is positively associated with serum sRAGE and negatively correlated with the levels of AGE and AGE/sRAGE. Methods Measurement of serum lipid levels from 100 patients allowed the separation into two groups (hypercholesterolemic and normocholesterolemic). Measurements of serum levels of AGE, sRAGE, and MDA were performed. Results Serum levels of sRAGE were lower, while the levels of AGE and AGE/sRAGE were higher in hypercholesterolemic subjects as compared with normocholesterolemic subjects. sRAGE levels are positively correlated with HDL, while they are negatively correlated with low-density lipoprotein, triglycerides, total cholesterol, and MDA in hypercholesterolemic subjects. Conclusions Hypercholesterolemia is positively correlated with serum AGE, AGE/sRAGE, and MDA. The effect of HDL-C may be due to increases in sRAGE and decreases in the levels of AGE and AGE/sRAGE. Hypercholesterolemia-induced atherosclerosis may be mediated through the AGE-RAGE axis; however, more research must be conducted.

Enhanced Extraction of Oil from Flaxseed (Linum usitatissimum L.) Using Microwave Pre-treatment

The effect of microwave (MW) pre-treatment on the extraction of flaxseed oil was investigated by hot extraction (HE). Nine MW pre-treatments were established, combining three MW radiation intensities (12, 18 and 24 W/g) and three MW radiation times of pre-treatment (90, 150 and 210 s). Extraction yield increased significantly with MW pre-treatments of flaxseed, and a max oil extraction yield (78.11%) can be obtained using MW pre-treatment at 18 W/g for 210 s. Scanning electronic microscopy showed that the microstructure of treated samples (18 W/g and 210 s) was modified compared with that of untreated samples. The fatty acid compositions (palmitic acid 5.85±0.01%, stearic acid 3.00±0.01%, oleic acid 17.64±0.07%, linoleic acid 16.16±0.06%, and linolenic acid 57.37±1.32%) of the oils extracted by the MW pre-treatments HE were similar with that of the conventional HE method. Results showed that fatty acid compositions of flaxseed oil were not affected by MW pre-treatments.

Reduction of cardiac and aortic cholesterol in hypercholesterolemic rats fed esters of phytosterol and omega-3 fatty acids

Sterol esters are currently gaining importance because of their recent recognition and application in the food and nutraceutical industries. Phytosterol esters have an advantage over phytosterols, naturally occurring antioxidants, with better fat solubility and compatibility. Antioxidants and hypocholesterolemic agents are known to reduce hypercholesterolemic atherosclerosis. The objective of the study was to determine the effects of different sterol esters on cardiac and aortic lipid profile and oxidative stress parameters and on the development of atherosclerosis in rats fed a high-cholesterol diet. Thirty six rats were divided into six groups: control group, hypercholesterolemic group and four experimental groups fed with EPA-DHA rich sitosterol ester in two different doses, 0.25 g/kg body wt/day and 0.5 g/kg body wt/day, and ALA rich sitosterol ester in two different doses, 0.25 g/kg body wt/day and 0.5 g/kg body wt/day. The sterol esters were gavaged to the rats once daily for 32 days. The cardiac and aortic total cholesterol, non-HDL cholesterol and triglyceride level which were elevated in hypercholesterolemia were significantly lowered by both the doses of sterol esters. Antioxidant enzyme activities were significantly decreased and peroxidation product, malondialdehyde was increased in hypercholesterolemia. But administration of both the sterol esters was able to increase enzyme activities and decrease MDA level in the tissues. Histological study of cardiac tissues showed fatty changes in hypercholesterolemic group which was reduced by treatment with sterol esters. The higher doses of sterol-ester caused better effects against hypercholesterolemic atherosclerosis.

Secoisolariciresinol diglucoside abrogates oxidative stress-induced damage in cardiac iron overload condition

Cardiac iron overload is directly associated with cardiac dysfunction and can ultimately lead to heart failure. This study examined the effect of secoisolariciresinol diglucoside (SDG), a component of flaxseed, on iron overload induced cardiac damage by evaluating oxidative stress, inflammation and apoptosis in H9c2 cardiomyocytes. Cells were incubated with 50 μ5M iron for 24 hours and/or a 24 hour pre-treatment of 500 μ M SDG. Cardiac iron overload resulted in increased oxidative stress and gene expression of the inflammatory mediators tumor necrosis factor-α, interleukin-10 and interferon γ, as well as matrix metalloproteinases-2 and -9. Increased apoptosis was evident by increased active caspase 3/7 activity and increased protein expression of Forkhead box O3a, caspase 3 and Bax. Cardiac iron overload also resulted in increased protein expression of p70S6 Kinase 1 and decreased expression of AMP-activated protein kinase. Pre-treatment with SDG abrogated the iron-induced increases in oxidative stress, inflammation and apoptosis, as well as the increased p70S6 Kinase 1 and decreased AMP-activated protein kinase expression. The decrease in superoxide dismutase activity by iron treatment was prevented by pre-treatment with SDG in the presence of iron. Based on these findings we conclude that SDG was cytoprotective in an in vitro model of iron overload induced redox-inflammatory damage, suggesting a novel potential role for SDG in cardiac iron overload.

Comparative pharmacokinetics of purified flaxseed and associated mammalian lignans in male Wistar rats

Consumption of flaxseed lignans is associated with various health benefits; however, little is known about the bioavailability of purified lignans in flaxseed. Data on their bioavailability and hence pharmacokinetics (PK) are necessary to better understand their role in putative health benefits. In the present study, we conducted a comparative PK analysis of the principal lignan of flaxseed, secoisolariciresinol diglucoside (SDG), and its primary metabolites, secoisolariciresinol (SECO), enterodiol (ED) and enterolactone (EL) in rats. Purified lignans were intravenously or orally administered to each male Wistar rat. SDG and its primary metabolites SECO, ED and EL were administered orally at doses of 40, 40, 10 and 10 mg/kg, respectively, and intravenously at doses of 20, 20, 5 and 1 mg/kg, respectively. Blood samples were collected at 0 (pre-dose), 5, 10, 15, 20, 30 and 45 min, and at 1, 2, 4, 6, 8, 12 and 24 h post-dosing, and serum samples were analysed. PK parameters and oral bioavailability of purified lignans were determined by non-compartmental methods. In general, administration of the flaxseed lignans SDG, SECO and ED demonstrated a high systemic clearance, a large volume of distribution and short half-lives, whereas administration of EL at the doses of 1 mg/kg (intravenously) and 10 mg/kg (orally administered) killed the rats within a few hours of dosing, precluding a PK analysis of this lignan. PK parameters of flaxseed lignans exhibited the following order: systemic clearance, SDG < SECO < ED; volume of distribution, SDG < SECO < ED; half-life, SDG < ED < SECO. The percentage of oral bioavailability was 0, 25 and < 1 % for SDG, SECO and ED, respectively.

The role of n - 6 and n - 3 polyunsaturated fatty acids in the manifestation of the metabolic syndrome in cardiovascular disease and non-alcoholic fatty liver disease

Cardiovascular disease (CVD) and non-alcoholic fatty liver disease (NAFLD) are manifestations of the metabolic syndrome. CVD remains the number one cause of mortality in the West, while NAFLD is the most common liver disease. Growing evidence suggests that polyunsaturated fatty acids (PUFA) influence risk factors including circulating lipids and inflammation on the development of CVD and NAFLD. N - 6 and n - 3 PUFA are comprised of distinct family members, which are increasingly recognized for their individual effects. Therefore, this review examines what is currently known about the specific effects of the major n - 3 and n - 6 PUFA on CVD and NAFLD. Overall, this review supports a beneficial effect of n - 3 PUFA and highlights distinctive effects between alpha-linolenic acid found in plant oils relative to marine derived eicosapentaenoic acid and docosahexaenoic acid. This review also highlights contrasting health effects between the n - 6 PUFA, linoleic and arachidonic acid.

Isolation, characterization and antihyperlipidemic activity of secoisolariciresinol diglucoside in poloxamer-407-induced experimental hyperlipidemia

CONTEXT

Linum usitatissimum L. (Linaceae), commonly known as flaxseed, is a good source of dietary fiber and lignans. Earlier we reported cardioprotective, antihyperlipidemic, and in vitro antioxidant activity of flax lignan concentrate (FLC) obtained from flaxseed.

OBJECTIVES

To isolate secoisolariciresinol diglucoside (SDG) from FLC and to evaluate the antihyperlipidemic activity of SDG in poloxamer-407 (P-407)-induced hyperlipidaemic mice.

MATERIAL AND METHODS

FLC was subjected to column chromatography and further subjected to preparative HPTLC to isolate SDG. The chemical structure of the isolated compound was elucidated by UV, IR, (1)H NMR, (13)C NMR, DEPT, COSY, HSQC, HMBC, ROESY, MS, and specific optical rotation was recorded. Further, we have investigated the antihyperlipidaemic effect of SDG (20 mg/kg) in P-407-induced hyperlipidaemic rats. Hyperlipidaemia was induced by intraperitoneal administration of P-407 (30% w/v). Serum lipid parameters such as total cholesterol (TC), triglycerides (TG), and high-density lipoprotein cholesterol (HDL-C) levels were measured.

RESULTS AND DISCUSSION

The structure and stereochemistry of the isolated compound were confirmed on the basis of 1D and 2D spectral data and characterized as SDG. Finally, isolated pure SDG was screened using a P-407-induced mice model for its antihyperlipidemic action using serum lipid parameters. The isolated SDG (20 mg/kg) significantly reduced serum cholesterol, triglyceride (p < 0.001), very low-density lipoprotein (p < 0.05), and non-significantly increased HDL-C.

CONCLUSION

Finally, it was concluded unequivocally that SDG showed antihyperlipidaemic effects in P-407-induced hyperlipidaemic mice. Isolated pure SDG confirms that SDG is beneficial in the prevention of experimental hyperlipidemia in laboratory animals.

Flaxseed Mitigates Acute Oxidative Lung Damage in a Mouse Model of Repeated Radiation and Hyperoxia Exposure Associated with Space Exploration

BACKGROUND

Spaceflight missions may require crewmembers to conduct extravehicular activities (EVA). Pre-breathe protocols in preparation for an EVA entail 100% hyperoxia exposure that may last for a few hours and be repeated 2-3 times weekly. Each EVA is associated with additional challenges such as low levels of total body cosmic/galactic radiation exposure that may present a threat to crewmember health. We have developed a mouse model of total body radiation and hyperoxia exposure and identified acute damage of lung tissues. In the current study we evaluated the usefulness of dietary flaxseed (FS) as a countermeasure agent for such double-hit exposures.

METHODS

We evaluated lung tissue changes 2 weeks post-initiation of exposure challenges. Mouse cohorts (n=5/group) were pre-fed diets containing either 0% FS or 10% FS for 3 weeks and exposed to: a) normoxia (Untreated); b) >95% O₂ (O₂); c) 0.25Gy single fraction gamma radiation (IR); or d) a combination of O₂ and IR (O₂+IR) 3 times per week for 2 consecutive weeks, where 8-hour hyperoxia treatments were spanned by normoxic intervals.

RESULTS

At 2 weeks post challenge, while control-diet fed mice developed significant lung injury and inflammation across all challenges, FS protected lung tissues by decreasing bronchoalveolar lavage fluid (BALF) neutrophils (p<0.003) and protein levels, oxidative tissue damage, as determined by levels of malondialdehyde (MDA) (p<0.008) and nitrosative stress as determined by nitrite levels. Lung hydroxyproline levels, a measure of lung fibrosis, were significantly elevated in mice fed 0% FS (p<0.01) and exposed to hyperoxia/radiation or the combination treatment, but not in FS-fed mice. FS also decreased levels of a pro-inflammatory, pro-fibrogenic cytokine (TGF-β1) gene expression levels in lung.

CONCLUSION

Flaxseed mitigated adverse effects in lung of repeat exposures to radiation/hyperoxia. This data will provide useful information in the design of countermeasures to early tissue oxidative damage associated with space exploration.

Potent Antihypertensive Action of Dietary Flaxseed in Hypertensive Patients

Flaxseed contains ω-3 fatty acids, lignans, and fiber that together may provide benefits to patients with cardiovascular disease. Animal work identified that patients with peripheral artery disease may particularly benefit from dietary supplementation with flaxseed. Hypertension is commonly associated with peripheral artery disease. The purpose of the study was to examine the effects of daily ingestion of flaxseed on systolic (SBP) and diastolic blood pressure (DBP) in peripheral artery disease patients. In this prospective, double-blinded, placebo-controlled, randomized trial, patients (110 in total) ingested a variety of foods that contained 30 g of milled flaxseed or placebo each day over 6 months. Plasma levels of the ω-3 fatty acid α-linolenic acid and enterolignans increased 2- to 50-fold in the flaxseed-fed group but did not increase significantly in the placebo group. Patient body weights were not significantly different between the 2 groups at any time. SBP was ≈10 mm Hg lower, and DBP was ≈7 mm Hg lower in the flaxseed group compared with placebo after 6 months. Patients who entered the trial with a SBP ≥140 mm Hg at baseline obtained a significant reduction of 15 mm Hg in SBP and 7 mm Hg in DBP from flaxseed ingestion. The antihypertensive effect was achieved selectively in hypertensive patients. Circulating α-linolenic acid levels correlated with SBP and DBP, and lignan levels correlated with changes in DBP. In summary, flaxseed induced one of the most potent antihypertensive effects achieved by a dietary intervention.

Vitamin E and regression of hypercholesterolemia-induced oxidative stress in kidney

Hypercholesterolemia (HC) is an independent risk factor for the onset and progression of renal disease. HC induces oxidative stress (OS) in the kidney; Vitamin E (Vit.E), an antioxidant, slows the progression of OS in the kidney. This study was to investigate if Vit.E regresses the HC-induced OS, and the regression is associated with an increase in the antioxidant reserve (AR). The studies were carried out in four groups of rabbits. The kidneys were removed under anesthesia. OS and AR in the renal tissue were assessed by measuring malondialdetyde (MDA) and chemiluminescent (CL) activity, respectively. High-cholesterol diet elevated the serum total cholesterol (TC), and the regular diet with or without Vit.E following a high-cholesterol diet reduced the serum TC to control levels. HC increased the MDA levels of kidney by 5.54-fold compared to control. The MDA contents of the kidneys in groups on regular diet with or without Vit.E were, respectively, 56 and 53 % lower than the control group. The CL activity in the control group was 12.15 ± 0.73 × 10(6) RLU/mg protein. The CL activity in HC group was 45.26 % lower than that in control, indicating an increase in AR. The regular diet with or without Vit.E following high-cholesterol diet normalized the CL activity/AR. In conclusion, HC increases OS in the kidney; reduction of serum cholesterol by regular diet regresses the renal OS but Vit.E does not regress HC-induced OS in kidney.

Mammary gene expression and activity of antioxidant enzymes and oxidative indicators in the blood, milk, mammary tissue and ruminal fluid of dairy cows fed flax meal

The effects of flax meal (FM) on the activity of antioxidant enzymes (superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT)) in the blood, mammary tissue and ruminal fluid, and oxidative stress indicators (thiobarbituric acid-reactive substances(TBARS) and 1,1-diphenyl-2-picrylhydrazyl-scavenging activity) in the milk, plasma and ruminal fluid of dairy cows were determined.The mRNA abundance of the antioxidant enzymes and oxidative stress-related genes was assessed in mammary tissue. A total of eight Holstein cows were used in a double 4 x 4 Latin square design. There were four treatments in the diet: control with no FM(CON) or 5% FM (5FM), 10% FM (10FM) and 15% FM (15FM). There was an interaction between treatment and time for plasma GPx and CAT activities. Cows supplemented with FM had a linear reduction in TBARS at 2 h after feeding, and there was no treatment effect at 0, 4 and 6 h after feeding. TBARS production decreased in the milk of cows fed the 5FM and 10FM diets. There was a linear increase in nuclear factor (erythroid-derived 2)-like 2 (NFE2L2) mRNA abundance in mammary tissue with FM supplementation.A linear trend for increased mRNA abundance of the CAT gene was observed with higher concentrations of FM. The mRNA abundance of CAT, GPx1, GPx3, SOD1, SOD2, SOD3 and nuclear factor of k light polypeptide gene enhancer in B-cells (NFKB) genes was not affected by the treatment. These findings suggest that FM supplementation can improve the oxidative status of Holstein cows as suggested by decreased TBARS production in ruminal fluid 2 h post-feeding and increased NFE2L2/nuclear factor-E2-related factor 2 (Nrf2) mRNA abundance in mammary tissue.

Radioprotective role in lung of the flaxseed lignan complex enriched in the phenolic secoisolariciresinol diglucoside (SDG)

While dietary wholegrain Flaxseed (FS) has potent anti-inflammatory, anti-fibrotic and antioxidant properties in murine models of acute and chronic lung injury, the main bioactive ingredient that contributes to these protective effects remains unknown. This study evaluated the lignan complex of FS (FLC) enriched in secoisolariciresinol diglucoside with respect to lung radioprotective and tumor radiosensitizing efficacy using a mouse model of thoracic radiation-induced pneumonopathy. C57/Bl6 mice were fed 0% FS, 10% FS, 10% FLC or 20% FLC for 3 weeks, then irradiated with a single fraction (13.5 Gy) of X-ray radiation treatment (XRT). Mouse survival was monitored for 4 months after irradiation and inflammatory lung parameters were evaluated in bronchoalveolar lavage (BAL) fluid. Gene and protein levels of protective antioxidant and phase II enzymes were evaluated in lung tissue using qPCR and protein levels were verified by immunoblotting. Prolonged administration of the FLC diet was well tolerated and was not associated with any toxicity. Importantly, comparable to the whole grain 10% FS diet, irradiated mice fed 10% and 20% FLC diets displayed improved survival. Improved hemodynamic measurements were also recorded in irradiated mice fed 10% FS or 10% FLC diet compared to irradiated 0% FS fed mice. Flaxseed lignan complex diet also attenuated polymorphonuclear infiltration and overall lung inflammation to levels comparable to those in nonirradiated mice. Flaxseed lignan complex, similarly to FS, up-regulated gene expression as well as protein levels of protective antioxidant enzymes such as heme oxygenase-1 (HO-1) and NAD(P)H quinone oxidoreductase 1 (NQO1). Dietary FLC induced radiosensitizing effects in our murine model of metastatic lung cancer. Importantly, protection of normal tissue does not thwart tumor cell death by radiation treatment. The dietary lignan complex of FS, mainly consisting of the phenolic secoisolariciresinol, is protective against radiation pneumonopathy in vivo while not hindering the tumoricidal effects of radiotherapy.

Antioxidants for chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a significant risk factor for premature cardiovascular disease and death. Increased oxidative stress in people with CKD has been implicated as a potential causative factor for some cardiovascular diseases. Antioxidant therapy may reduce cardiovascular mortality and morbidity in people with CKD.

OBJECTIVES

To examine the benefits and harms of antioxidant therapy on mortality and cardiovascular events in people with CKD stages 3 to 5; dialysis, and kidney transplantation patients.

SEARCH METHODS

We searched the Cochrane Renal Group's specialised register (July 2011), CENTRAL (Issue 6, 2011), MEDLINE (from 1966) and EMBASE (from 1980).

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) investigating the use of antioxidants for people with CKD, or subsets of RCTs reporting outcomes for participants with CKD.

DATA COLLECTION AND ANALYSIS

Titles and abstracts were screened independently by two authors who also performed data extraction using standardised forms. Results were pooled using the random effects model and expressed as either risk ratios (RR) or mean difference (MD) with 95% confidence intervals (CI).

MAIN RESULTS

We identified 10 studies (1979 participants) that assessed antioxidant therapy in haemodialysis patients (two studies); kidney transplant recipients (four studies); dialysis and non-dialysis CKD patients (one study); and patients requiring surgery (one study). Two additional studies reported the effect of an oral antioxidant inflammation modulator in patients with CKD (estimated glomerular filtration rate (eGFR) 20 to 45 mL/min/1.73 m²), and post-hoc findings from a subgroup of people with mild-to-moderate renal insufficiency (serum creatinine ≥125 μmol/L) respectively. Interventions included different doses of vitamin E (two studies); multiple antioxidant therapy (three studies); co-enzyme Q (one study); acetylcysteine (one study); bardoxolone methyl (one study); and human recombinant superoxide dismutase (two studies).Compared with placebo, antioxidant therapy showed no clear overall effect on cardiovascular mortality (RR 0.95, 95% CI 0.70 to 1.27; P = 0.71); all-cause mortality (RR 0.93, 95% CI 0.76 to 1.14; P = 0.48); cardiovascular disease (RR 0.78, 95% CI 0.52 to 1.18; P = 0.24); coronary heart disease (RR 0.71, 95% CI 0.42 to 1.23; P = 0.22); cerebrovascular disease (RR 0.91, 95% CI 0.63 to 1.32; P = 0.63); or peripheral vascular disease (RR 0.54, 95% CI 0.26 to 1.12; P = 0.10). Subgroup analyses found no evidence of significant heterogeneity based on proportions of males (P = 0.99) or diabetes (P = 0.87) for cardiovascular disease. There was significant heterogeneity for cardiovascular disease when studies were analysed by CKD stage (P = 0.003). Significant benefit was conferred by antioxidant therapy for cardiovascular disease prevention in dialysis patients (RR 0.57, 95% CI 0.41 to 0.80; P = 0.001), although no effect was observed in CKD patients (RR 1.06, 95% CI 0.84 to 1.32; P = 0.63).Antioxidant therapy was found to significantly reduce development of end-stage of kidney disease (ESKD) (RR 0.50, 95% CI 0.25 to 1.00; P = 0.05); lowered serum creatinine levels (MD 1.10 mg/dL, 95% CI 0.39 to 1.81; P = 0.003); and improved creatinine clearance (MD 14.53 mL/min, 95% CI 1.20 to 27.86; P = 0.03). Serious adverse events were not significantly increased by antioxidants (RR 2.26, 95% CI 0.74 to 6.95; P = 0.15).Risk of bias was assessed for all studies. Studies that were classified as unclear for random sequence generation or allocation concealment reported significant benefits from antioxidant therapy (RR 0.57, 95% CI 0.41 to 0.80; P = 0.001) compared with studies at low risk of bias (RR 1.06, 95% CI 0.84 to 1.32; P = 0.63).

AUTHORS' CONCLUSIONS

Although antioxidant therapy does not reduce the risk of cardiovascular and all-cause death or major cardiovascular events in people with CKD, it is possible that some benefit may be present, particularly in those on dialysis. However, the small size and generally suboptimal quality of the included studies highlighted the need for sufficiently powered studies to confirm this possibility. Current evidence suggests that antioxidant therapy in predialysis CKD patients may prevent progression to ESKD; this finding was however based on a very small number of events. Further studies with longer follow-up are needed for confirmation. Appropriately powered studies are needed to reliably assess the effects of antioxidant therapy in people with CKD.

Vitamin E slows the progression of hypercholesterolemia-induced oxidative stress in heart, liver and kidney

Vitamin E suppresses the hypercholesterolemia-induced oxidative stress in the heart. The objectives were to investigate if: (a) hypercholesterolemia-induced oxidative stress is similar in heart, liver, and kidney, and is dependent upon duration of hypercholesterolemia; and (b) vitamin E slows the progression of oxidative stress in these organs. The rabbits were assigned to 4 groups: I, regular diet (2 months); II, 0.25 % cholesterol diet (2 months); III, 0.25 % cholesterol diet (4 months); and IV, 0.25 % cholesterol diet (2 months) followed by 0.25 % cholesterol diet plus vitamin E (2 months). Blood samples were collected before and at the end of protocol for the measurement of total cholesterol (TC). Hearts, livers, and kidneys were removed at the end of the protocol under anesthesia for the measurement of oxidative parameters, malondialdehyde (MDA), and chemiluminescence (CL). The basal MDA levels in the heart, liver, and kidney of rabbits in Group I were similar, but increased to 14.65-, 3.18-, and 10.35-fold, respectively, with hypercholesterolemia. The increases in MDA levels were dependent upon the duration of hypercholesterolemia. Vitamin E did not alter the TC levels, but reduced the MDA levels in all organs. Hypercholesterolemia and vitamin E had variable effects on CL activity. In conclusion, (i) hypercholesterolemia induces oxidative stress in heart, liver, and kidney, the heart being the most and the liver the least susceptible to oxidative stress; (ii) oxidative stress is positively associated with duration of hypercholesterolemia; and (iii) vitamin E slows the progression of oxidative stress in these organs.

The α-linolenic acid content of flaxseed can prevent the atherogenic effects of dietary trans fat

Dietary intake of industrially hydrogenated trans fatty acids (TFA) has been associated with coronary heart disease. Dietary flaxseed can inhibit atherosclerosis induced by dietary cholesterol. The aim of this study was to determine whether supplementing the diet with flaxseed could protect against atherosclerosis induced by a diet enriched in TFA. Low-density lipoprotein receptor-deficient (LDLr−/−) mice were fed 1 of 14 experimental diets for 14 wk containing one of two fat sources [regular (pork/soy) or trans fat] at two concentrations (4 or 8%) and supplemented with or without dietary cholesterol (2%), whole ground flaxseed, or one of the components of flaxseed [α-linolenic acid (ALA), defatted fiber, or lignan]. Adding flaxseed to the diet partially mitigated the rise in circulating cholesterol levels induced by the cholesterol-enriched diet. Atherosclerosis was stimulated by TFA and/or cholesterol. Including milled flaxseed to an atherogenic diet significantly reduced atherosclerosis compared with the groups that consumed cholesterol and/or TFA. ALA was the only component within flaxseed that could inhibit the atherogenic action of cholesterol and/or TFA on its own. Dietary flaxseed protects against atherosclerotic development induced by TFA and cholesterol feeding through its content of ALA.

Presence of caffeic acid in flaxseed lignan macromolecule

Phenolic compounds were extracted from defatted flaxseeds using ethanol-dioxane (1:1, v/v). The crude extract obtained was purified using Amberlite XAD-16 column chromatography with water and methanol as mobile phases. RP-HPLC and SE-HPLC showed a lignan macromolecule (LM) as a dominant phenolic compound in the purified extract. After the alkaline hydrolysis of LM caffeic acid glucoside (CaAG) was isolated using a semi-preparative HPLC and its structure was confirmed by LC-ESI-MS. In LM of the investigated flaxseed, one molecule of caffeic acid corresponded with five molecules of p-coumaric acid and two molecules of ferulic acid. The presence of caffeic acid in the lignan molecule might be very beneficial due to its high antioxidant activity.

Effects of linseed consumption for a short period of time on lipid profile and atherosclerotic lesions in rabbits fed a hypercholesterolaemic diet

Linseed contains biologically active substances, such as lignans, fibres and linoleic acid, which are believed to provide cardioprotective effects. The objective of the present study was to assess the potential hypolipaemic, anti-atherogenic and anti-inflammatory effects of linseed consumption using an experimental animal model, with rabbits fed a hypercholesterolaemic diet (1 % cholesterol extracted from lyophilised egg). A total of twenty white male rabbits were selected and divided into two groups: group I (GI), control group, ten rabbits; group II (GII), ten rabbits. The animals were fed a hypercholesterolaemic diet for 56 d. For the GII diet, ground linseed was added from day 29 through to day 56. Animals underwent aortic arch and descending aorta dissection on day 56 for histological, morphometric and immunohistochemical analysis. At the end of the experiment, GII animals presented with lower levels of total cholesterol (TC, 10 068·3 v. 16 767·0 mg/l; P < 0·05) and lower levels of LDL-cholesterol (LDL-C; 10 743·2 v. 15 961·2 mg/l; P < 0·05) when compared with the GI control group. There was no significant difference in serum HDL-cholesterol and TAG between the two groups. Almost all animals exhibited type III atherosclerotic lesions in the descending aorta. There was no statistically significant difference between the intima area and the intima:media layer area ratio in both groups. There was no difference between the positive areas for vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 molecules between the groups. Linseed consumption showed hypolipaemic action by reducing LDL-C and TC levels; however, this cholesterol-lowering effect did not reduce the atherosclerotic lesions induced by a hypercholesterolaemic diet (1 % cholesterol) for a short period of time.

Cardioprotective activity of flax lignan concentrate extracted from seeds of Linum usitatissimum in isoprenalin induced myocardial necrosis in rats

The objective of the study was to evaluate the cardioprotective activity of flax lignan concentrate (FLC) in isoprenalin (ISO) induced cardiotoxicity in rats. Male Wistar rats (200–230 g) were divided into three groups. Group I: control, Group II: isoprenalin, Group III: FLC (500 mg/kg, p.o.) orally for 8 days and in group II and III isoprenalin 5.25 mg/kg, s.c. on day 9 and 8.5 mg/kg on day 10. On day 10 estimation of marker enzymes in serum and haemodynamic parameters were recorded. Animals were sacrificed, histology of heart was performed. Isoprenalin showed cardiotoxicity, manifested by increased levels of marker enzymes and increased heart rate. FLC treatment reversed these biochemical changes significantly compared with ISO group. The cardiotoxic effect of isoprenalin was less in FLC pretreated animals, which was confirmed in histopathological alterations. Haemodynamic, biochemical alteration and histopathological results suggest a cardioprotective protective effect of FLC in isoprenalin induced cardiotoxicity.