Plant sterols in atherosclerosis prevention

Overview of Natural Supplements for the Management of Diabetes and Obesity

Bioactive compounds found in various natural sources, such as fruits, vegetables, and herbs, have been studied for their potential benefits in managing obesity and diabetes. These compounds include polyphenols, flavonoids, other antioxidants, fiber, and certain fatty acids. Studies have found that these compounds may improve insulin sensitivity, regulate blood sugar levels, and promote weight loss. However, the effects of these compounds can vary depending on the type and amount consumed, as well as individual factors, such as genetics and lifestyle. Nutraceutical substances have multifaceted therapeutic advantages, and they have been reported to have disease-prevention and health-promoting properties. Several clinically used nutraceuticals have been shown to target the pathogenesis of diabetes mellitus, obesity, and metabolic syndrome and their complications and modulate various clinical outcomes favorably. This review aims to highlight and comment on some of the most prominent natural components used as antidiabetics and in managing obesity.

Stigmasterol Protects Against Steatohepatitis Induced by High-Fat and High-Cholesterol Diet in Mice by Enhancing the Alternative Bile Acid Synthesis Pathway

BACKGROUND

Hepatic cholesterol accumulation is a significant risk factor in the progression of nonalcoholic fatty liver disease (NAFLD) to steatohepatitis. However, the precise mechanism by which stigmasterol (STG) mitigates this process remains unclear.

OBJECTIVES

This study aimed to investigate the potential mechanism underlying the protective effect of STG in mice with NAFLD progressing to steatohepatitis while being fed a high-fat and high-cholesterol (HFHC) diet.

METHODS

Male C57BL/6 mice were fed an HFHC diet for 16 wk to establish the NAFLD model. Subsequently, the mice received STG or a vehicle via oral gavage while continuing the HFHC diet for an additional 10 wk. The study evaluated hepatic lipid deposition and inflammation as well as the expression of key rate-limiting enzymes involved in the bile acid (BA) synthesis pathways. BAs in the colonic contents were quantified using ultra-performance liquid chromatography-tandem mass spectrometry.

RESULTS

Compared with the vehicle control group, STG significantly reduced hepatic cholesterol accumulation (P < 0.01) and suppressed the gene expression of NLRP3 inflammasome and interleukin-18 (P < 0.05) in the livers of HFHC diet-fed mice. The total fecal BA content in the STG group was nearly double that of the vehicle control group. Additionally, the administration of STG increased the concentrations of representative hydrophilic BAs in the colonic contents (P < 0.05) along with the upregulation of gene and protein expression of CYP7B1 (P < 0.01). Furthermore, STG enhanced the α-diversity of the gut microbiota and partially reversed the alterations in the relative abundance of the gut microbiota induced by the HFHC diet.

CONCLUSIONS

STG mitigates steatohepatitis by enhancing the alternative pathway for BA synthesis.

Pathophysiology of atherosclerosis: Association of risk factors and treatment strategies using plant-based bioactive compounds

Under physiological conditions, endothelial cells act as protective barrier which prevents direct contact of blood with circulating factors via production of tissue plasminogen activator. Risk factors of metabolic disorders are responsible to induce endothelial dysfunction and may consequently lead to prognosis of atherosclerosis. This article summarizes the process of atherosclerosis which involves number of sequences including formation and interaction of AGE-RAGE, activation of polyol pathway, protein kinase C, and hexosamine-mediated pathway. All these mechanisms can lead to the development of oxidative stress which may further aggravate condition. Different pharmacological interventions are being used to treat atherosclerosis, however, these might be associated with mild to severe side effects. Therefore, plant-based bioactive compounds having potential to combat and prevent atherosclerosis in diabetic patients are attaining recent focus. By understanding process of development and mechanisms involved in atherosclerotic plaque formation, these bioactive compounds can be better option for future therapeutic interventions for atherosclerosis treatment. PRACTICAL APPLICATIONS: Atherosclerosis is one of major underlying disorders of cardiovascular diseases which occur through multiple mechanisms and is associated with metabolic disorders. Conventional therapeutic interventions are not only used to treat atherosclerosis, but are also commonly associated with mild to severe side effects. Therefore, nowadays, bioactive compounds having potential to combat and prevent atherosclerosis in diabetic patients are preferred. By understanding mechanisms involved in atherosclerotic plaque formation, bioactive compounds can be better understood for treatment of atherosclerosis. In this manuscript, we have focused on treatment strategies of atherosclerosis using bioactive compounds notably alkaloids and flavonoids having diverse pharmacological and therapeutic potentials with special focus on the mechanism of action of these bioactive compounds suitable for treatment of atherosclerosis. This manuscript will provide the scientific insights of bioactive compounds to researchers who are working in the area of drug discovery and development to control pathogenesis and development of atherosclerosis and its associated cardiometabolic disorders.

Bioavailability of nanotechnology-based bioactives and nutraceuticals

Bioaccessibility and bioavailability of some hydrophobic bioactives (e.g., carotenoids, polyphenols, fat-soluble vitamins, phytosterols and fatty acids) are limited due to their low water solubility, and in some instances low chemical stability. Nanotechnology involving nanometric (r<500nm) delivery systems, can be used to improve the solubility and thus enhance the bioaccessibility and bioavailability of hydrophobic compounds. Nanometric delivery systems, derived from food grade phospholipids and biopolymers adopt many forms, including liposomes, micelles, micro/nanoemulsions, particles, polyelectrolyte complexes, and hydrogels. The small particle sizes and customized materials used to create delivery systems confer their unique properties such as higher stability and/or resistance to enzymatic activity in the gastrointestinal tract. This chapter provides an overview of bioaccessibility and bioavailability of different classes of hydrophobic bioactive compounds, focusing on nanometric delivery systems and methods of evaluation.

In silico and in vivo analysis to identify the antidiabetic activity of beta sitosterol in adipose tissue of high fat diet and sucrose induced type-2 diabetic experimental rats

Adipose tissue is the primary site of storage for excess energy as triglyceride and it helps in synthesizing a number of biologically active compounds that regulate metabolic homeostasis. Consumption of high dietary fat increases stored fat mass and is considered as a main risk factor for metabolic diseases. Beta-sitosterol (β-sitosterol) is a plant sterol. It has the similar chemical structure like cholesterol. Clinical and experimental studies have shown that β-sitosterol has anti-diabetic, hypolipidemic, anti-cancer, anti-arthritic, and hepatoprotective role. However, effect of β-sitosterol on insulin signaling molecules and glucose oxidation has not been explored. Hence in the present study we aimed to discover the protective role of β-sitosterol on the expression of insulin signaling molecules in the adipose tissue of high-fat diet and sucrose-induced type-2 diabetic experimental rats. Effect dose of β-sitosterol (20 mg/kg b.wt, orally for 30 days) was given to high fat diet and sucrose-induced type-2 diabetic rats to study its anti-diabetic activity. Results of the study showed that the treatment with β-sitosterol to diabetes-induced rats normalized the altered levels of blood glucose, serum insulin and testosterone, lipid profile, oxidative stress markers, antioxidant enzymes, insulin receptor (IR), and glucose transporter 4 (GLUT4) proteins. Our present findings indicate that β-sitosterol improves glycemic control through activation of IR and GLUT4 in the adipose tissue of high fat and sucrose-induced type-2 diabetic rats. Insilico analysis also coincides with invivo results. Hence it is very clear that β-sitosterol can act as potent antidiabetic agent.

Legume consumption and CVD risk: a systematic review and meta-analysis

Objective

The aim of the present study was to systematically review and perform a meta-analysis of prospective cohort studies exploring the association between dietary legume consumption and CVD risk, including CHD and stroke.

Design

The PubMed and EMBASE databases were searched up to December 2015. A meta-analysis of the highestv.lowest (reference) category of dietary legume consumption was performed through random-effects models.

Results

Fourteen studies conducted on eleven cohorts and accounting for a total of 367 000 individuals and 18 475 cases of CVD (7451 CHD and 6336 stroke cases) were considered for the analyses. Compared with lower legume consumption, the highest category of exposure was associated with a decreased risk of 10 % in both CVD and CHD (relative risk=0·90; 95 % CI 0·84, 0·97) with no or little evidence of heterogeneity and no publication bias. Null results were found regarding legume consumption and stroke risk. No substantial confounding factors were evident in stratified analyses.

Conclusions

Legume consumption was associated with lower risk of CVD. Legumes’ intrinsic characteristics, because they are often part of an overall healthy diet, or because they are a substitute for unhealthy sources of protein may potentially explain the current findings.

Diet and cardiovascular disease

This paper describes the importance of diet in cardiovascular disease prevention. Different aspects of diet are discussed: nutrients, single foods/food groups and dietary patterns. The evidence regarding the impact of diet on intermediate risk factors (such as blood pressure and cholesterol levels) and the impact on cardiovascular endpoints are discussed.

Plant sterols and atherosclerosis

PURPOSE OF REVIEW

Plant sterols as ingredients to functional foods are recommended for lowering LDL cholesterol. However, there is an ongoing discussion whether the use of plant sterols is safe.

RECENT FINDINGS

Genetic analyses showed that common variants of the ATP binding cassette transporter G8 (ABCG8) and ABO genes are associated with elevated circulating plant sterols and higher risk for cardiovascular disease. However, these data do not prove a causal role for plant sterols in atherosclerosis because the risk alleles in ABCG8 and ABO are also related to elevated total and LDL cholesterol levels. The ABO locus exhibits still further pleiotropy. Moreover, analyses in the general population indicated that moderately elevated circulating plant sterols are not correlated with present or future vascular disease. In agreement, novel studies using food frequency questionnaires, studies in experimental animals, and dietary intervention studies support that ingestion of plant sterols may be beneficial to cardiovascular health.

SUMMARY

Taken together, current evidence supports the recommendations for the use of plant sterols as LDL cholesterol-lowering agents. Nevertheless, a prospective, randomized, controlled, double-blinded, intervention trial conclusively showing that plant sterol supplementation will prevent hard cardiovascular endpoints is not available to date.