Isoflavone glycitein diminished plasma cholesterol in female golden Syrian hamsters

Understanding hypocholesterolemic activity of soy isoflavones: Completing the puzzle through computational simulations

The hypocholesterolemic activity of soy isoflavones has been studied, but the exact mechanism underlying the activity remains unclear. This study reveals the proposed mechanism of the cholesterol-lowering effect of soy isoflavones by computational simulations. Daidzin, Glycitin, Genistin, Daidzein, Glycitein, Genistein, Glyceollin I, Glyceollin II, and Glyceollin III were selected to be analyzed their interaction with 3-Hydroxy-3-Methyl-Glutaryl-Coenzyme A Reductase (HMGCR) and Sterol Regulatory Element-Binding Protein 2 (SREBP2) as key factors in cholesterol biosynthesis as well as Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) as a common target for hypercholesterolemia. Protein-isoflavones interaction was analyzed using AutoDock. According to binding energy calculations, a total of five out of those nine isoflavones, including Glycitin, Genistin, Genistein, Glyceollin II, and Glyceollin III, were favored to be a HMGCR inhibitor but not with SREBP2 and PCSK9. Those isoflavones were then compared with Simvastatin as known inhibitor of HMGCR. Isoflavone with binding energy lower than Simvastatin then directed to molecular dynamics using YASARA and headed into toxicity estimations. Almost all of those isoflavones could bind with HMGCR with better stability than Simvastatin according to molecular dynamics simulations. Toxicity prediction filtered two out of the five isoflavones mentioned earlier as the proper candidate to be an HMGCR inhibitor. Those isoflavones were Genistin and Genistein. In summary, the hypocholesterolemic activity of soy isoflavones may occur by blocking the cholesterol biosynthesis pathway.Communicated by Ramaswamy H. Sarma.

Flavonoids and Their Metabolites: Prevention in Cardiovascular Diseases and Diabetes

The occurrence of atherosclerosis and diabetes is expanding rapidly worldwide. These two metabolic disorders often co-occur, and are part of what is often referred to as the metabolic syndrome. In order to determine future therapies, we propose that molecular mechanisms should be investigated. Once the aetiology of the metabolic syndrome is clear, a nutritional intervention should be assessed. Here we focus on the protective effects of some dietary flavonoids, and their metabolites. Further studies may also pave the way for development of novel drug candidates.

Dietary daidzein, but not genistein, has a hypocholesterolemic effect in non-ovariectomized and ovariectomized female Sprague-Dawley rats on a cholesterol-free diet

We compared the effects of two major isoflavones, daidzein and genistein, on lipid metabolism in rats. Daidzein (150 mg/kg diet), genistein (150 mg/kg diet), daidzein and genistein (1:1, 300 mg/kg diet), or control diets were fed to 4 groups of 6-week-old ovariectomized (Ovx) and non-Ovx Sprague Dawley rats for 4 weeks. Dietary daidzein, but not genistein, reduced serum and hepatic total cholesterol levels significantly relative to that by the control group, regardless of whether the rats had undergone ovariectomy. Genistein did not exhibit any physiological effects on lipid levels, but did affect genes involved in cholesterol metabolism. These results indicate that daidzein and genistein may influence lipid regulation via differing modes of action.

Antiherpes evaluation of soybean isoflavonoids

The antiviral effects of soybean isoflavonoids have been investigated recently, especially those of genistein. It has been reported that this isoflavone is able to inhibit herpes simplex virus (HSV) replication, which is associated with skin and epithelial mucosa infections. The treatment of these infections with antiherpes drugs has resulted in the emergence of resistant viral strains. Based on this evidence, the aim of this study was to investigate the anti-HSV effects of soybean isoflavonoids: daidzein, genistein, glycitein, and coumestrol. Genistein and coumestrol inhibited HSV-1 (KOS and 29R strains, which are acyclovir sensitive and acyclovir resistant, respectively) and HSV-2 (333 strain) replication, whereas no antiviral effects were detected for daidzein and glycitein. The mechanisms of action were evaluated by different methodological strategies. Coumestrol affected the early stages of viral infection, and both compounds were able to reduce HSV-1 protein expression, as well as HSV-2 cell-to-cell spread.

Regulation of the immune response by soybean isoflavones

Soybeans are rich in immuno-modulatory isoflavones such as genistein, daidzein, and glycitein. These isoflavones are well-known antioxidants, chemopreventive and anti-inflammatory agents. Several epidemiological studies suggest that consumption of traditional soy food containing isoflavones is associated with reduced prevalence of chronic health disorders. Isoflavones are considered to be phytoestrogens because of their ability to bind to estrogen receptors. The literature is extensive on the chemistry, bio-availability, and bio-activity of isoflavones. However, their effects on immune response are yet to be fully understood, but are beginning to be appreciated. We review the role of isoflavones in regulation of the immune response and their potential clinical applications in immune-dysfunction. Special emphasis will be made regarding in vivo studies including humans and animal model systems.

Effects of probiotic bacteria, isoflavones and simvastatin on lipid profile and atherosclerosis in cholesterol-fed rabbits: a randomized double-blind study

Background

Much attention has been drawn to different alternative strategies for cardiovascular disease prevention. Objective: The aim of the present study was to observe and compare the effects of Enterococcus faecium CRL183 (probiotic microorganism), an isoflavones mixture and simvastatin (drug used to treat hypercholesterolemia) on lipid parameters and atherosclerosis development in rabbits with induced hypercholesterolemia.

Methods

The animals were randomly allocated to 5 experimental groups (n = 6) for 60 days: control (C) that did not consume cholesterol, hypercholesterolemic (H) that consumed an atherogenic diet (1.0% cholesterol wt/wt), hypercholesterolemic plus E. faecium (HE), hypercholesterolemic plus isoflavone (HI) and hypercholesterolemic plus simvastatin (HS). Total and HDL-cholesterol and triglycerides were determined by enzymatic methods; non-HDL-C was calculated by subtracting HDL-C from total cholesterol; and atherosclerosis was presented as the percentage of lesion area, relative to the total area from the aorta segment analyzed.

Results

Simvastatin significantly reduced the tot cholesterol (16%) and non-HDL-C level (17%) and increased the HDL-C (98%), compared to group H. E. faecium raised the HDL-C level by 43.3% (P < 0.05). Isoflavone decreased the total cholesterol and non-HDL-C concentrations (9%), but this effect was not statistically significant. At the end of the treatments, groups HE and HS had significantly lower levels of triglycerides in relation to H and HI. The atherosclerotic lesion area in the aortic arch was not different between groups. The extent of atherosclerosis in the thoracic and abdominal aorta was reduced in the groups HI and HS by 22.7% and 26.7% respectively, but this effect was not significant (P > 0.05).

Conclusion

The results indicated that probiotic microorganism E. faecium CRL 183 could be used to improve the lipid profile as an alternative or an adjuvant for drug therapy. The effectiveness of simvastatin in the management of blood lipid was confirmed. There were no effects of soy isoflavones, E. faecium and simvastatin on atherosclerosis development.

Cholesterol-lowering nutraceuticals and functional foods

Epidemiological studies have demonstrated that elevated levels of plasma total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) are the major risk factors for coronary heart disease (CHD), whereas high concentrations of plasma high-density lipoprotein cholesterol (HDL-C) and a low ratio of TC to HDL-C are protective against CHD. A relationship between plasma TC and the risk of CHD is well established at concentrations above 240 mg/dL. In addition to the use of three main classes of cholesterol-lowering medications, including HMG-CoA reductase inhibitors, anion-exchange resins, and fibrates, a nutritionally balanced diet that reduces saturated fat and cholesterol intake has traditionally been the first goal of dietary therapy in lowering plasma TC. In recent years, nutraceuticals and functional foods have attracted much interest as possible alternative therapies for lowering plasma TC, especially for hypercholesterolemia patients, whose blood cholesterol level is marginally high (200-240 mg/dL) but not high enough to warrant the prescription of cholesterol-lowering medications. This review summarizes the findings of recent studies on the production, application, efficacy, and mechanisms of popular cholesterol-lowering nutraceuticals and functional foods.