Effects of Pharmacologic Dose of Resveratrol Supplementation on Oxidative/Antioxidative Status Biomarkers in Nonalcoholic Fatty Liver Disease Patients: A Randomized, Double-Blind, Placebo-Controlled Trial

Resveratrol ameliorates mitochondrial biogenesis and reproductive outcomes in women with polycystic ovary syndrome undergoing assisted reproduction: a randomized, triple-blind, placebo-controlled clinical trial

BACKGROUND

This study was designed to examine the effect of resveratrol on mitochondrial biogenesis, oxidative stress (OS), and assisted reproductive technology (ART) outcomes in individuals with polycystic ovary syndrome (PCOS).

METHODS

Fifty-six patients with PCOS were randomly assigned to receive 800 mg/day of resveratrol or placebo for 60 days. The primary outcome was OS in follicular fluid (FF). The secondary outcome involved assessing gene and protein expression related to mitochondrial biogenesis, mitochondrial DNA (mtDNA) copy number, and adenosine triphosphate (ATP) content in granulosa cells (GCs). ART outcomes were evaluated at the end of the trial.

RESULTS

Resveratrol significantly reduced the total oxidant status (TOS) and oxidative stress index (OSI) in FF (P = 0.0142 and P = 0.0039, respectively) while increasing the total antioxidant capacity (TAC) (P < 0.0009). Resveratrol consumption also led to significant increases in the expression of critical genes involved in mitochondrial biogenesis, including peroxisome proliferator-activated receptor gamma coactivator (PGC-1α) and mitochondrial transcription factor A (TFAM) (P = 0.0032 and P = 0.0003, respectively). However, the effect on nuclear respiratory factor 1 (Nrf-1) expression was not statistically significant (P = 0.0611). Resveratrol significantly affected sirtuin1 (SIRT1) and PGC-1α protein levels (P < 0.0001 and P = 0.0036, respectively). Resveratrol treatment improved the mtDNA copy number (P < 0.0001) and ATP content in GCs (P = 0.0014). Clinically, the resveratrol group exhibited higher rates of oocyte maturity (P = 0.0012) and high-quality embryos (P = 0.0013) than did the placebo group. There were no significant differences between the groups in terms of chemical or clinical pregnancy rates (P > 0.05).

CONCLUSIONS

These findings indicate that resveratrol may be a promising therapeutic agent for patients with PCOS undergoing assisted reproduction.

TRIAL REGISTRATION NUMBER

http://www.irct.ir ; IRCT20221106056417N1; 2023 February 09.

Bioactive compounds from nature: Antioxidants targeting cellular transformation in response to epigenetic perturbations induced by oxidative stress

Oxidative stress results from a persistent imbalance in oxidation levels that promotes oxidants, playing a crucial role in the early and sustained phases of DNA damage and genomic and epigenetic instability, both of which are intricately linked to the development of tumors. The molecular pathways contributing to carcinogenesis in this context, particularly those related to double-strand and single-strand breaks in DNA, serve as indicators of DNA damage due to oxidation in cancer cases, as well as factors contributing to epigenetic instability through ectopic expressions. Oxidative stress has been considered a therapeutic target for many years, and an increasing number of studies have highlighted the promising effectiveness of natural products in cancer treatment. In this regard, we present significant research on the therapeutic targeting of oxidative stress using natural molecules and underscore the essential role of oxidative stress in cancer. The consequences of stress, especially epigenetic instability, also offer significant therapeutic prospects. In this context, the use of natural epi-drugs capable of modulating and reorganizing the epigenetic network is beginning to emerge remarkably. In this review, we emphasize the close connections between oxidative stress, epigenetic instability, and tumor transformation, while highlighting the role of natural substances as antioxidants and epi-drugs in the anti-tumoral context.

Impact of Adherence to the Mediterranean Diet on Antioxidant Status and Metabolic Parameters in NAFLD Patients: A 24-Month Lifestyle Intervention Study

BACKGROUND

The Mediterranean Diet (MedDiet) is recognized as a healthy dietary pattern. Non-alcoholic fatty liver disease (NAFLD) is characterized by the excessive accumulation of fat in the liver.

OBJECTIVES

To assess the antioxidant status in erythrocytes, plasma, and peripheral blood mononuclear cells (PBMCs) of NAFLD patients following a 24-month lifestyle intervention based on the MedDiet. Adult patients (n = 40; aged 40-60 years) diagnosed with NAFLD by magnetic resonance imaging were divided into two groups based on their adherence to the MedDiet. Consumption was assessed using a validated 143-item semiquantitative Food Frequency Questionnaire. Anthropometrics, biochemistry parameters, intrahepatic fat contents (IFC), antioxidants, and inflammatory biomarkers were measured in plasma and erythrocytes before and after the intervention.

RESULTS

After the intervention, body mass index (BMI) and plasma levels of total cholesterol, low-density lipoprotein cholesterol (LDL-chol), triglycerides, malondialdehyde (MDA), and cytokeratin-18 (CK18) decreased, and high-density lipoprotein cholesterol (HDL-chol) increased. Participants with high adherence to MedDiet showed lower IFC, hepatic enzyme (AST, ALT, and GGT), glycemia, oxidase LDL (oxLDL) plasma levels, and erythrocyte MDA levels. Higher antioxidant activity (erythrocyte catalase-CAT, superoxide dismutase-SOD, glutathione peroxidase-GPx, glutathione reductase-GRd, and total glutathione-GSH as well as PBMCs-CAT gene expression) was observed in these patients, along with a reduction of PBMCs reactive oxygen species production and Toll-like receptor 4 (TLR4) expression. Inverse associations were observed between adherence to the MedDiet and BMI, glycemia, AST, IFC, and CK18 plasma levels and oxLDL, CAT, SOD, and GRd activities in erythrocytes. A significant linear regression was observed between adherence to the MedDiet and antioxidant score.

CONCLUSIONS

Adherence to the MedDiet is associated with improved plasma and PBMC antioxidant and inflammatory biomarker profiles and high antioxidant defences in erythrocytes.

Does Resveratrol Improve Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)?

Metabolic dysfunction-associated steatotic liver disease (MASLD) is influenced by a variety of factors, including environmental and genetic factors. The most significant outcome is the alteration of free fatty acid and triglyceride metabolism. Lipotoxicity, impaired autophagy, chronic inflammation, and oxidative stress, as well as coexisting insulin resistance, obesity, and changes in the composition of gut microbiota, are also considered crucial factors in the pathogenesis of MASLD. Resveratrol is a polyphenolic compound that belongs to the stilbene subgroup. This review summarises the available information on the therapeutic effects of resveratrol against MASLD. Resveratrol has demonstrated promising antisteatotic, antioxidant, and anti-inflammatory activities in liver cells in in vitro and animal studies. Resveratrol has been associated with inhibiting the NF-κB pathway, activating the SIRT-1 and AMPK pathways, normalizing the intestinal microbiome, and alleviating intestinal inflammation. However, clinical studies have yielded inconclusive results regarding the efficacy of resveratrol in alleviating hepatic steatosis or reducing any of the parameters found in MASLD in human patients. The lack of homogeneity between studies, low bioavailability of resveratrol, and population variability when compared to animal models could be the reasons for this.

Resveratrol for the Management of Human Health: How Far Have We Come? A Systematic Review of Resveratrol Clinical Trials to Highlight Gaps and Opportunities

Resveratrol has long been proposed as being beneficial to human health across multiple morbidities, yet there is currently no conclusive clinical evidence to advocate its recommendation in any healthcare setting. A large cohort with high-quality clinical data and clearly defined biomarkers or endpoints are required to draw meaningful conclusions. This systematic review compiles every clinical trial conducted using a defined dose of resveratrol in a purified form across multiple morbidities to highlight the current 'state-of-play' and knowledge gaps, informing future trial designs to facilitate the realisation of resveratrol's potential benefits to human health. Over the last 20 years, there have been almost 200 studies evaluating resveratrol across at least 24 indications, including cancer, menopause symptoms, diabetes, metabolic syndrome, and cardiovascular disease. There are currently no consensus treatment regimens for any given condition or endpoint, beyond the fact that resveratrol is generally well-tolerated at a dose of up to 1 g/day. Additionally, resveratrol consistently reduces inflammatory markers and improves aspects of a dysregulated metabolism. In conclusion, over the last 20 years, the increasing weight of clinical evidence suggests resveratrol can benefit human health, but more large, high-quality clinical trials are required to transition this intriguing compound from health food shops to the clinic.

The effect of resveratrol supplementation on biomarkers of liver health: A systematic review and meta-analysis of randomized controlled trials

This study aimed to evaluate the effect of resveratrol on liver biomarkers in adult participants, using systematic review and meta-analysis of randomized controlled trials. PubMed, Scopus, Web of Science and Cochran Library was searched, up to October 2021. The pooled effects were calculated using a random-effects model and expressed as weighted mean difference and 95% confidence interval. The methodological quality of studies as well as certainty of evidence were assessed by standard tools. Thirty-seven relevant trials were found. Although overall analysis found no significant change, subgroup analysis showed a significant improvement in alanine aminotransferase (ALT; -7.79 U/L) and glutamyl transferase (-6.0 U/L) in patients with liver disorders, and ALT (-2.22 U/L) in younger adults; however, high-dose supplementation (>1,000 mg/day) appeared to increase alkaline phosphatase concentration (+5.07 U/L). ALT also increased in older adults (+2.33 U/L) following resveratrol supplementation. We found resveratrol did not have a significant effect on liver health in the general population. However, resveratrol could be effective in patients with liver disorders. Our findings also suggest that high-dose resveratrol administration and supplementation in older adults should be performed with caution. Further high-quality clinical trials are also needed to firmly establish the clinical efficacy of resveratrol.

trans-Chalcone inhibits transforming growth factor-β1 and connective tissue growth factor-dependent collagen expression in the heart of high-fat diet-fed rats

Objective: Non-alcoholic fatty liver disease (NAFLD) is one of the main risk factors for cardiovascular mortality and morbidity. This study, for the first time, explored the effects of trans-chalcone on cardiac expressions of myocardial fibrosis-related genes, including transforming growth factor -β1 (TGF-β1), connective tissue growth factor (CTGF/CCN2), and collagen type I.Materials and methods: Twenty-eight rats were randomly divided into four groups: control, received 10% tween 80; chalcone, received trans-chalcone; HFD, received high-fat diet (HFD) and 10% tween 80; HFD + chalcone, received HFD and trans-chalcone, by once-daily gavage for 6 weeks. Finally, cardiac expression levels of TGF-β1, CTGF, and collagen type I were determined.Results: HFD feeding increased mRNA levels of collagen type I, TGF-β1, and CTGF in the heart of rats. However, trans-chalcone inhibited HFD-induced changes.Conclusions: trans-Chalcone can act as a cardioprotective compound by inhibiting TGF-β1 and CTGF-dependent stimulation of collagen type I synthesis in the heart of HFD-fed rats.

Polyphenols and atherosclerosis: A critical review of clinical effects on LDL oxidation

Atherosclerosis is a major etiology of cardiovascular disease that causes considerable mortality. Oxidized low-density lipoprotein (oxLDL) is a fundamental attributor to atherosclerosis. Therefore, there seems to be an essential place for antioxidant therapy besides the current treatment protocols for coronary heart disease. Polyphenols are a class of compounds with substantial antioxidant properties that have shown the ability to reduce LDL oxidation in preclinical studies. However, clinical evidence has not been as conclusive although offering many promising signs. This review aims to examine the trials that have evaluated how dietary intake of polyphenols in different forms might influence the oxidation of LDL. Lowering the circulating cholesterol, incorporation into LDL particles, and enhancing systemic antioxidant activity are among the main mechanisms of action for polyphenols for lowering oxLDL. On the other hand, the population under study significantly affects the impact on oxLDL, as the type of the supplement and phenolic content. To conclude, although the polyphenols might decrease inflammation and enhance endothelial function via lowering oxLDL, there are still many gaps in our knowledge that need to be filled with further high-quality studies.

Resveratrol from Dietary Supplement to a Drug Candidate: An Assessment of Potential

Resveratrol (RVT) is a well known phyto-chemical and is widely used in dietary supplements and botanical products. It shows a wide range of pharmacological/beneficial effects. Therefore, it can be a potential candidate to be developed as phyto-pharmaceutical. Multiple diseases are reported to be treated by the therapeutic effect of RVT since it has antioxidant, anti-cancer activity and anti-inflammatory activities. It also has a major role in diabetes, arthritis, cardiac disorder and platelet aggregation etc. The major requirements are establishments regarding safety, efficacy profile and physicochemical characterization. As it is already being consumed in variable maximum daily dose, there should not be a major safety concern but the dose needs to be established for different indications. Clinical trials are also being reported in different parts of the world. Physicochemical properties of the moiety are also well reported. Moreover, due to its beneficial effect on health it leads to the development of some intellectual property in the form of patents.

Effects of Calorie Restricted Diet on Oxidative/Antioxidative Status Biomarkers and Serum Fibroblast Growth Factor 21 Levels in Nonalcoholic Fatty Liver Disease Patients: A Randomized, Controlled Clinical Trial

Oxidative stress plays a fundamental role in the development and progression of nonalcoholic fatty liver disease (NAFLD). This study aimed to investigate the effects of a calorie-restricted (CR) diet on oxidative/anti-oxidative status in patients with NAFLD and the potential mediating role of fibroblast growth factor 21 (FGF-21) in this regard. This randomized, controlled clinical trial was carried out on sixty patients with NAFLD aged 20 to 60 years with body mass index (BMI) ranging from 25 to 35 kg/m2. Participants were randomly assigned to either the CR diet group (received a prescribed low-calorie diet for twelve weeks, n = 30) or the control group (n = 30). Fasting blood samples, anthropometric measurements, dietary intake, and physical activity data were collected for all participants at baseline and at the end of the trial. Significant reductions in weight, BMI, waist circumference, and serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were observed in the CR diet group compared to the control group (all p < 0.05). Liver steatosis grade, serum levels of malondialdehyde (MDA), total antioxidant capacity (TAC), and FGF-21, as well as erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities did not show significant changes in the CR group when compared to the controls at the end of the study (p > 0.05). CR diet with moderate weight loss has some favorable effects on NAFLD but was not able to modify oxidative/anti-oxidative status in these patients. Future studies are warranted to target the effects of long-term interventions with a greater weight loss in this patient population.

Modulation of Oxidative Stress-Induced Senescence during Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease is characterized by disturbed lipid metabolism and increased oxidative stress. These conditions lead to the activation of different cellular response mechanisms, including senescence. Cellular senescence constitutes an important response to injury in the liver. Recent findings show that chronic oxidative stress can induce senescence, and this might be a driving mechanism for NAFLD progression, aggravating the disturbance of lipid metabolism, organelle dysfunction, pro-inflammatory response and hepatocellular damage. In this context, the modulation of cellular senescence can be beneficial to ameliorate oxidative stress-related damage during NAFLD progression. This review focuses on the role of oxidative stress and senescence in the mechanisms leading to NAFLD and discusses the possibilities to modulate senescence as a therapeutic strategy in the treatment of NAFLD.

A Molecular Insight into the Role of Antioxidants in Nonalcoholic Fatty Liver Diseases

Nonalcoholic fatty liver disease (NAFLD) defines fat accumulation in the liver, and it is commonly associated with metabolic syndromes like diabetes and obesity. Progressive NAFLD leads to nonalcoholic steatohepatitis (NASH) and ultimately causes cirrhosis and hepatocellular carcinoma, and NASH is currently a frequent cause of liver transplantation. Oxidative stress is often contributed to the progression of NAFLD, and hence, antioxidants such as silymarin, silybin, or silibinin, pentoxifylline, resveratrol, and vitamins A, C, and E are used in clinical trials against NAFLD. Silymarin induces the peroxisome proliferator-activated receptor α (PPARα), a fatty acid sensor, which promotes the transcription of genes that are required for the enzymes involved in lipid oxidation in hepatocytes. Silybin inhibits sterol regulatory element-binding protein 1 and carbohydrate response element-binding protein to downregulate the expression of genes responsible for de novo lipogenesis by activating AMP-activated protein kinase phosphorylation. Pentoxifylline inhibits TNF-α expression and endoplasmic reticulum stress-mediated inflammatory nuclear factor kappa B (NF-κB) activation. Thus, it prevents NAFLD to NASH progression. Resveratrol inhibits methylation at Nrf-2 promoters and NF-κB activity via SIRT1 activation in NAFLD conditions. However, clinically, resveratrol has not shown promising beneficial effects. Vitamin C is beneficial in NAFLD patients. Vitamin E is not effectively regressing hepatic fibrosis. Hence, its combination with antifibrotic agents is used as an adjuvant to produce a synergistic antifibrotic effect. However, to date, none of these antioxidants have been used as a definite therapeutic agent in NAFLD patients. Further, these antioxidants should be studied in NAFLD patients with larger populations and multiple endpoints in the future.

Therapeutic Effects of Resveratrol on Nonalcoholic Fatty Liver Disease Through Inflammatory, Oxidative Stress, Metabolic, and Epigenetic Modifications

The prevalence of nonalcoholic fatty liver disease (NAFLD) is increasing around the world, in association with the progressive elevation in overweight and obesity. The accumulation of lipids in NAFLD patients contributes to the development of insulin resistance, inflammation and oxidative stress in hepatocytes, and alteration of blood lipids and glycaemia. There are currently no effective pharmacological therapies for NAFLD, although lifestyle and dietary modifications targeting weight reduction are among the prevailing alternative approaches. For this reason, new approaches should be investigated. The natural polyphenol resveratrol represents a potential new treatment for management of NAFLD due to anti-inflammatory and antioxidant properties. Although preclinical trials have demonstrated promising results of resveratrol against NALFD, the lack of conclusive results creates the need for more trials with larger numbers of patients, longer time courses, and standardized protocols.

Design of Hepatic Targeted Drug Delivery Systems for Natural Products: Insights into Nomenclature Revision of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD), recently renamed metabolic-dysfunction-associated fatty liver disease (MAFLD), affects a quarter of the worldwide population. Natural products have been extensively utilized in treating NAFLD because of their distinctive advantages over chemotherapeutic drugs, despite the fact that there are no approved drugs for therapy. Notably, the limitations of many natural products, such as poor water solubility, low bioavailability in vivo, low hepatic distribution, and lack of targeted effects, have severely restricted their clinical application. These issues could be resolved via hepatic targeted drug delivery systems (HTDDS) that boost clinical efficacy in treating NAFLD and decrease the adverse effects on other organs. Herein an overview of natural products comprising formulas, single medicinal plants, and their crude extracts has been presented to treat NAFLD. Also, the clinical efficacy and molecular mechanism of active monomer compounds against NAFLD are systematically discussed. The targeted delivery of natural products via HTDDS has been explored to provide a different nanotechnology-based NAFLD treatment strategy and to make suggestions for natural-product-based targeted nanocarrier design. Finally, the challenges and opportunities put forth by the nomenclature update of NAFLD are outlined along with insights into how to improve the NAFLD therapy and how to design more rigorous nanocarriers for the HTDDS. In brief, we summarize the up-to-date developments of the NAFLD-HTDDS based on natural products and provide viewpoints for the establishment of more stringent anti-NAFLD natural-product-targeted nanoformulations.

Chronic liver disease and oxidative stress - a narrative review

Introduction: Oxidative stress underlies the pathophysiology of various etiologies of chronic liver disease and contributes to the development of hepatocarcinogenesis.Areas covered: This review focuses on the impact of oxidative stress in various etiologies of chronic liver disease such as alcoholic liver disease (ALD), nonalcoholic steatohepatitis (NASH), hepatitis B virus (HBV), and hepatitis C virus (HCV) infection. The efficacy of antioxidants in laboratory, animal, and clinical studies in chronic liver disease is also reviewed.Expert opinion: Currently, there are limited targeted pharmacotherapeutics for NASH and no pharmacotherapeutics for ALD and antioxidant supplementation may be useful in these conditions to improve liver function and reverse fibrosis. Antioxidants may also be used in patients with HBV or HCV infection to supplement antiviral therapies. Specific genotypes of antioxidant and prooxidant genes render patients more susceptible to liver cirrhosis and hepatocellular carcinoma while other individual characteristics like age, genotype, and metabolomic profiling can influence the efficacy of antioxidants on CLD. More research needs to be done to establish the safety, efficacy, and dosage of antioxidants and to establish the ideal patient profile that will benefit the most from antioxidant treatment.

Effects of resveratrol supplementation on bone quality: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The results from clinical trials have revealed that the effects of resveratrol supplementation on bone mineral density (BMD) and bone biomarkers are inconsistent. Our objective was to determine the effects of resveratrol supplementation on BMD and serum bone biomarkers.

METHODS

PubMed, Cochrane library, EMBASE, Web of science and Scopus were searched up to August 24, 2020. Two reviewers independently performed the articles search and screen according to defined selection criteria. The study quality of the randomized controlled trials (RCTs) was evaluated with the Cochrane scoring system. Heterogeneity among studies was examined by Cochrane Q test. Retrieved data were pooled after mean differences (MD) were computed between two groups for BMD and serum biomarkers. Subgroup analyses were performed to evaluate a potential difference in terms of dose of resveratrol and intervention duration. Sensitivity analysis was executed by omitting studies with imputed values in order to evaluate the influence of these studies on the overall results.

RESULTS

Ten eligible studies involving 698 subjects were included in this meta-analysis with 401 participants receiving resveratrol and 297 receiving placebo. Supplementation of resveratrol had no statistically significant effects on areal bone mineral density (aBMD) at lumbar spine (MD: -0.02, 95% CI: - 0.05, 0.01, p = 0.26, I² = 6%), total hip BMD (MD: -0.01, 95% CI: - 0.04, 0.02, p = 0.65, I² = 0%), and whole body BMD (MD: 0.00, 95% CI: - 0.02, 0.02, p = 0.74, I² = 0%). Supplementation of resveratrol also did not result in significant change in bone serum markers, including serum alkaline phosphatase (ALP), bone alkaline phosphatase (BAP), osteocalcin (OCN), procollagen I N-terminal propeptide (PINP), C-terminal telopeptide of type I collagen (CTX) and parathyroid hormone (PTH). Subgroup analysis showed the effect of resveratrol supplementation on BMD and serum bone markers were similar in trails of different doses, intervention duration, and pathological conditions of the participants.

CONCLUSION

Resveratrol supplementation did not show any significant effect on BMD or serum bone markers with the current evidence. Further investigation with more well-organized multicentre randomized trial is warranted.

Nutritional supplementation for nonalcohol-related fatty liver disease: a network meta-analysis

BACKGROUND

The prevalence of non-alcohol-related fatty liver disease (NAFLD) varies between 19% and 33% in different populations. NAFLD decreases life expectancy and increases risks of liver cirrhosis, hepatocellular carcinoma, and the requirement for liver transplantation. Uncertainty surrounds relative benefits and harms of various nutritional supplements in NAFLD. Currently no nutritional supplement is recommended for people with NAFLD.

OBJECTIVES

• To assess the benefits and harms of different nutritional supplements for treatment of NAFLD through a network meta-analysis • To generate rankings of different nutritional supplements according to their safety and efficacy SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, Science Citation Index Expanded, Conference Proceedings Citation Index-Science, the World Health Organization International Clinical Trials Registry Platform, and trials registers until February 2021 to identify randomised clinical trials in people with NAFLD.

SELECTION CRITERIA

We included only randomised clinical trials (irrespective of language, blinding, or status) for people with NAFLD, irrespective of method of diagnosis, age and diabetic status of participants, or presence of non-alcoholic steatohepatitis (NASH). We excluded randomised clinical trials in which participants had previously undergone liver transplantation.

DATA COLLECTION AND ANALYSIS

We performed a network meta-analysis with OpenBUGS using Bayesian methods whenever possible and calculated differences in treatments using hazard ratios (HRs), odds ratios (ORs), and rate ratios with 95% credible intervals (CrIs) based on an available-case analysis, according to National Institute of Health and Care Excellence Decision Support Unit guidance.

MAIN RESULTS

We included in the review a total of 202 randomised clinical trials (14,200 participants). Nineteen trials were at low risk of bias. A total of 32 different interventions were compared in these trials. A total of 115 trials (7732 participants) were included in one or more comparisons. The remaining trials did not report any of the outcomes of interest for this review. Follow-up ranged from 1 month to 28 months. The follow-up period in trials that reported clinical outcomes was 2 months to 28 months. During this follow-up period, clinical events related to NAFLD such as mortality, liver cirrhosis, liver decompensation, liver transplantation, hepatocellular carcinoma, and liver-related mortality were sparse. We did not calculate effect estimates for mortality because of sparse data (zero events for at least one of the groups in the trial). None of the trials reported that they measured overall health-related quality of life using a validated scale. The evidence is very uncertain about effects of interventions on serious adverse events (number of people or number of events). We are very uncertain about effects on adverse events of most of the supplements that we investigated, as the evidence is of very low certainty. However, people taking PUFA (polyunsaturated fatty acid) may be more likely to experience an adverse event than those not receiving an active intervention (network meta-analysis results: OR 4.44, 95% CrI 2.40 to 8.48; low-certainty evidence; 4 trials, 203 participants; direct evidence: OR 4.43, 95% CrI 2.43 to 8.42). People who take other supplements (a category that includes nutritional supplements other than vitamins, fatty acids, phospholipids, and antioxidants) had higher numbers of adverse events than those not receiving an active intervention (network meta-analysis: rate ratio 1.73, 95% CrI 1.26 to 2.41; 6 trials, 291 participants; direct evidence: rate ratio 1.72, 95% CrI 1.25 to 2.40; low-certainty evidence). Data were sparse (zero events in all groups in the trial) for liver transplantation, liver decompensation, and hepatocellular carcinoma. So, we did not perform formal analysis for these outcomes. The evidence is very uncertain about effects of other antioxidants (antioxidants other than vitamins) compared to no active intervention on liver cirrhosis (HR 1.68, 95% CrI 0.23 to 15.10; 1 trial, 99 participants; very low-certainty evidence). The evidence is very uncertain about effects of interventions in any of the remaining comparisons, or data were sparse (with zero events in at least one of the groups), precluding formal calculations of effect estimates. Data were probably because of the very short follow-up period (2 months to 28 months). It takes follow-up of 8 to 28 years to detect differences in mortality between people with NAFLD and the general population. Therefore, it is unlikely that differences in clinical outcomes are noted in trials providing less than 5 to 10 years of follow-up.

AUTHORS' CONCLUSIONS

The evidence indicates considerable uncertainty about effects of nutritional supplementation compared to no additional intervention on all clinical outcomes for people with non-alcohol-related fatty liver disease. Accordingly, high-quality randomised comparative clinical trials with adequate follow-up are needed. We propose registry-based randomised clinical trials or cohort multiple randomised clinical trials (study design in which multiple interventions are trialed within large longitudinal cohorts of patients to gain efficiencies and align trials more closely to standard clinical practice) comparing interventions such as vitamin E, prebiotics/probiotics/synbiotics, PUFAs, and no nutritional supplementation. The reason for the choice of interventions is the impact of these interventions on indirect outcomes, which may translate to clinical benefit. Outcomes in such trials should be mortality, health-related quality of life, decompensated liver cirrhosis, liver transplantation, and resource utilisation measures including costs of intervention and decreased healthcare utilisation after minimum follow-up of 8 years (to find meaningful differences in clinically important outcomes).

Natural Polyphenols in Metabolic Syndrome: Protective Mechanisms and Clinical Applications

Metabolic syndrome (MetS) is a chronic disease, including abdominal obesity, dyslipidemia, hyperglycemia, and hypertension. It should be noted that the occurrence of MetS is closely related to oxidative stress-induced mitochondrial dysfunction, ectopic fat accumulation, and the impairment of the antioxidant system, which in turn further aggravates the intracellular oxidative imbalance and inflammatory response. As enriched anti-inflammatory and antioxidant components in plants, natural polyphenols exhibit beneficial effects, including improving liver fat accumulation and dyslipidemia, reducing blood pressure. Hence, they are expected to be useful in the prevention and management of MetS. At present, epidemiological studies indicate a negative correlation between polyphenol intake and MetS incidence. In this review, we summarized and discussed the most promising natural polyphenols (including flavonoid and non-flavonoid drugs) in the precaution and treatment of MetS, including their anti-inflammatory and antioxidant properties, as well as their regulatory functions involved in glycolipid homeostasis.

The Effects of Resveratrol on Oxidative Stress Markers: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

OBJECTIVE

Recent trial studies have found that resveratrol supplementation beneficially reduces oxidative stress marker, but, there is no definitive consensus on this context. The present systematic review and meta-analysis aimed to investigate the effect of resveratrol supplementation on oxidative stress parameters.

METHODS

We searched databases of Pubmed, Scopus and Cochrane Library up to December 2018 with no language restriction. Studies were reviewed according to preferred reporting items for systematic reviews and meta-analyses (PRISMA) and Cochrane handbook. To compare the effects of resveratrol with placebo, weighted mean difference (WMD) with 95% confidence intervals (CI) were pooled based on the random-effects model.

RESULTS

Among sixteen clinical trials, we found that resveratrol supplementation increased GPx serum levels significantly (WMD: 18.61; 95% CI: 8.70 to 28.52; P<0.001) but had no significant effect on SOD concentrations (WMD: 1.01; 95% CI: -0.72 to 2.74; P= 0.25), MDA serum levels (WMD: -1.43; 95% CI: -3.46 to 0.61; P = 0.17) and TAC (WMD: -0.09; 95% CI: -0.29 to 0.11; P = 0.36) compared to placebo. Finally, we observed that resveratrol supplementation may not have a clinically significant effect on oxidative stress.

CONCLUSION

However, the number of human trials is limited in this context, and further large prospective clinical trials are needed to confirm the effect of resveratrol supplement on oxidative stress markers.

Nanomaterial Complexes Enriched With Natural Compounds Used in Cancer Therapies: A Perspective for Clinical Application

Resveratrol and quercetin are natural compounds contained in many foods and beverages. Reports indicate implications for the health of the general population; on the other hand the use of both compounds has interesting results for the treatment of many diseases as cardiovascular affections, diabetes, Alzheimer’s disease, viral and bacterial infections among others. Based on their capacities described as anti-inflammatory, antioxidant, and anti-aging, resveratrol and quercetin showed antiproliferative and anticancer activity specifically in maligned cells. These molecular characteristics trigger the pharmacological repurposing of both compounds and improved its research for treating different cancer types with interesting results at in vitro, in vivo, and clinical trial studies. Meanwhile, the development of different systems of drug release in specific sites as nanomaterials and specifically the nanoparticles, potentiates the personal treatment perspective in conjunct with the actual cancer therapies; regularly invasive and aggressive, the perspective of nanomedicine as higher effective and lower invasive has gained popularity. Knowledge of molecular interactions of resveratrol and quercetin in diseases confirms the evidence of multiple benefits, while the multiple analyses suggested a positive response for the treatment and diagnostics of cancer in different stages, including at metastatic stage. The present work reviews the reports related to the impact of resveratrol and quercetin in cancer treatment and its effects when the antioxidants are encapsulated in different nanoparticle systems, which improve the prospects of cancer treatment.

The efficacy of novel metabolic targeted agents and natural plant drugs for nonalcoholic fatty liver disease treatment: A PRISMA-compliant network meta-analysis of randomized controlled trials

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a highly prevalent chronic liver disease characterized by excess accumulation of fat in hepatocytes. Because no drug has been approved for NAFLD treatment, this work analyzed the effects of agents resulting from 2 research hotspots, metabolic target agents, and natural plant drugs, on NAFLD with network meta-analysis.

METHODS

Public databases were searched through August 14, 2020. Randomized controlled trials that compared obeticholic acid, elafibranor, cenicriviroc, selonsertib, curcumin, silymarin, and resveratrol to placebo were included. Liver pathology improvement, hepatic biochemical indicators, and lipid metabolism indicators were analyzed.

RESULTS

Thirty-five studies were included in the meta-analysis. Obeticholic acid was found to significantly increase the frequency of liver biopsy improvement compared to placebo (OR: 2.10; 95% CI: 1.60, 2.77). The ranking results among the hepatic biochemical indicators showed that obeticholic acid (94.9%) and elafibranor (86.3%) have a relative advantage in reducing alanine aminotransferase (ALT) levels, and obeticholic acid also had an advantage (95.4%) in reducing aspartate aminotransferase (AST) levels. Considering lipid metabolic indicators, elafibranor (expSMD: 0.01; 95% CI: 0.00, 0.05; SUCRA: 100%), and obeticholic acid (expSMD: 0.48; 95% CI: 0.28,0.84; SUCRA: 75.6%) significantly reduced triglyceride (TG) levels compared with placebo; moreover, obeticholic acid, but not elafibranor, caused a serious increase in total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels and a decrease in high-density lipoprotein cholesterol (HDL-C) levels.

CONCLUSIONS

Novel metabolic targeted agents generally have better effects than natural plant drugs, especially obeticholic acid, and elafibranor. However, obeticholic acid showed serious adverse effects such as increasing LDL-C levels and decreasing HDL-C levels. Curcumin showed potential advantages for NAFLD but lacked statistical significance.

The Role of Resveratrol in Liver Disease: A Comprehensive Review from In Vitro to Clinical Trials

Many studies have shown that resveratrol has a lot of therapeutic effects on liver disorders. Its administration can significantly increase the survival rate after liver transplantation, reduce fat deposition and ischemia-induced necrosis and apoptosis in Wistar rats. Resveratrol can provide Liver protection against chemical, cholestatic, and alcohol-mediated damage. It can improve glucose metabolism and lipid profile, reduce liver fibrosis, and steatosis. Additionally, it is capable of altering the fatty acid composition of the liver cells. Resveratrol may be a potential treatment option for the management of non-alcoholic fatty liver disease (NAFLD) due to its anti-inflammatory, antioxidant, and calorie-restricting effects. There are also studies that have evaluated the effect of resveratrol on lipid and liver enzyme profiles among patients with metabolic syndrome (MetS) and related disorders. Based on the extent of liver disease worldwide and the need to find new treatment possibilities, this review critically examines current in vitro and in vivo preclinical studies and human clinical studies related to liver protection.

Resveratrol inhibits MRGPRX2-mediated mast cell activation via Nrf2 pathway

Mast cells (MCs) are crucial effectors in inflammation and allergic reactions. The Mas-related G-protein-coupled receptor X2 (MRGPRX2) was the MC-specific receptor and play a key role in IgE-independent allergic reactions. The activation of the Nuclear factor erythroid derived 2-related factor 2 (Nrf2) is involved in IgE-mediated MC degranulation. Resveratrol (Res) is a polyphenolic compound in red wine and has been reported to exert a variety of pharmacological effects. In the current study, we investigated the effect of Res in regulating MRGPRX2-mediated MC activation and its underlyingmechanism. We demonstrated that Res reduced compound 48/80 (C48/80)-induced calcium flux in MCs and inhibited MCs degranulation in vitro. Res also suppressed C48/80-induced hind paw extravasation, active systemic anaphylaxis, and MCs degranulation in mouse models of pseudo-allergy in vivo. Furthermore, PCR and immunohistochemistry assay suggest that Res up-regulates Nrf2 expression and Nrf2 inhibitor attenuates the protective effects of Res. In conclusion, Res exerts an inhibitory effect on MRGPRX2-mediated MCs activation by targeting Nrf2 pathway and may present a promising new therapeutic agent for the treatment of MRGPRX2-dependent anaphylactoid reactions.

Efficacy of resveratrol supplementation in patients with nonalcoholic fatty liver disease: A systematic review and meta-analysis of clinical trials

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and refers to the accumulation of triglycerides in hepatocytes. Recent studies have showed that resveratrol (antioxidant of grape) can be effective in the treatment of NAFLD through its inhibitory effect on lipid accumulation.

METHOD

We systematically searched databases including: ISI web of science, Scopus, PubMed and Embase by using related keywords. Then, by considering inclusion and exclusion criteria, appropriate articles were selected. All the analyses were conducted in Review Manager (RevMan) Version 5.3.

RESULTS

Finally, 6 RCTs were included in meta-analysis and systematic review. Our results showed that resveratrol supplementation significantly reduced levels of TNF-alpha (SMD = -0.46; 95% CI (-0.78, 0.14); P = 0.005) and hs-CRP (SMD = -0.53; 95% CI (-1.01, -0.05); P = 0.030), but for other markers (BW, BMI, WC, HC, WHR, SBP, DBP, ALT, AST, GGT, ALP, bilirubin, TC, TG, HDL, LDL, LDL to HDL ratio, apo-A1, apo-B, insulin, HOMA-IR, glucose, creatinine and IL-6), no significant change was observed.

CONCLUSION

Overall, the results of the present study show that resveratrol supplementation does not affect the management of NAFLD although it can improve some inflammatory markers.

Resveratrol Metabolites Are Able to Reduce Steatosis in Cultured Hepatocytes

Steatosis is characterized primarily by excessive lipid accumulation in the form of triglycerides in the liver. Although resveratrol shows a low bioavailability, it has significant positive effects on steatosis. The aim of this study was to analyze whether some phase II and microbial resveratrol metabolites (trans-resveratrol-4'-O-glucuronide (R-4G); trans-resveratrol-3-O-glucuronide (R-3G); trans-resveratrol-3-O-sulfate (R-S) and dihydro-resveratrol (DH-R) were effective in reducing hepatocyte fat accumulation. An in vitro model mimicking the hepatocyte situation in fatty liver was developed by incubating mouse AML12 hepatocytes with palmitic acid (PA). For cell treatments, hepatocytes were incubated with 1, 10, or 25 µM resveratrol or its metabolites. Triglycerides and cell viability were assessed using commercial kits. Protein expression of enzymes and transporters involved in triglyceride metabolism were analyzed by western blot. We show for the first time that resveratrol and all the tested metabolites, at 1 µM, partially prevented lipid accumulation induced by the saturated fatty acid PA in AML12 hepatocytes. This effect was mainly due to the inhibition of de novo lipogenesis. This demonstrates that the low bioavailability of resveratrol is not as big a problem as it was thought to be, because resveratrol metabolites contribute to the delipidating effects of the parent compound.

The Evaluation of Effective Drugs for the Treatment of Non-Alcoholic Fatty Liver Disease: A Systematic Review and Network Meta-Analysis

Purpose: Non-alcoholic fatty liver disease (NAFLD) and steatohepatitis are two forms of fatty liver disease with benign and malignant nature, respectively. These two conditions can cause an increased risk of liver cirrhosis and hepatocellular carcinoma. Given the importance and high prevalence of NAFLD, it is necessary to investigate the results of different studies in related scope to provide a clarity guarantee of effectiveness. Therefore, this systematic review and meta-analysis aim to study the efficacy of various medications used in the treatment of NAFLD. Methods: A systematic search of medical databases identified 1963 articles. After exclusion of duplicated articles and those which did not meet our inclusion criteria, eta-analysis was performed on 84 articles. Serum levels of alanine aminotransferase (ALT), aspartate amino transferase (AST) were set as primary outcomes and body mass index (BMI), hepatic steatosis, and NAFLD activity score (NAS) were determined as secondary outcomes. Results: Based on the P-score of the therapeutic effects on the non-alcoholic steatohepatitis (NASH), we observed the highest efficacy for atorvastatin, tryptophan, orlistat, omega-3 and obeticholic acid for reduction of ALT, AST, BMI, steatosis and NAS respectively. Conclusion: This meta-analysis showed that atorvastatin. life-style modification, weight loss, and BMI reduction had a remarkable effect on NAFLD-patients by decreasing aminotransferases.

Effects of Resveratrol Supplementation in Patients with Non-Alcoholic Fatty Liver Disease-A Meta-Analysis

Non-alcoholic fatty liver disease (NAFLD) is regarded as one of the most common liver pathologies in many societies. Resveratrol, as a phenolic compound with powerful antioxidant and anti-inflammatory properties exerting positive effects on the lipid profile and lipid accumulation and also on insulin resistance, appears to be an effective, natural, and safe complementary treatment option in NAFLD therapy. This meta-analysis was undertaken to evaluate the effects of resveratrol supplementation in NAFLD patients. To this end, scientific databases PubMed/Medline/Embase were searched up to 19 March 2020. We included seven randomized clinical trials (RCTs) with a total of 302 patients with NAFLD. In all the trials included in the analysis, resveratrol was administered daily over periods between 56 and 180 days in doses ranging from 500 mg to 3000 mg a day. The results of this meta-analysis reveal that resveratrol supplementation, irrespective of the dose or duration, did not affect the analyzed parameters (p < 0.05). The sole exception was an increase in alanine aminotransferase following the administration of resveratrol (p = 0.041). Currently available evidence is insufficient to confirm the efficacy of resveratrol in the management of NAFLD. Due to the inconsistencies between the existing scientific reports, a number of which found a positive effect on NAFLD-related parameters; further research in this area is needed.

Combined Amelioration of Prebiotic Resveratrol and Probiotic Bifidobacteria on Obesity and Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) and obesity are becoming increasingly common globally and characteristic as gut microbiota disturbance. Supplement of probiotics is considered as a promising strategy for NAFLD and obesity treatment. However, this effect varied from each other in clinical trials. We proposed that combination with a prebiotic substrate may improve the effects of probiotics. Thus, in this study, we investigated the separated and combined effects of Bifidobacteria and resveratrol (RSV) against obesity and NAFLD. NAFLD was caused by high-fat diet (HFD) feeding for 8 weeks. HFD-treated mice were orally treated with B. longum (1 × 10⁹ CFU/mouse/day), RSV (100 mg/kg/day), and both of them from the fifth week. HFD feeding caused obesity and NAFLD as indicated by significantly increased body and liver weights, liver steatosis, elevated serum transaminases and lipid profiles, increased inflammation and imbalanced redox status. Based on these physical and biochemical parameters, inflammatory and antioxidant markers, individual administration of B. longum and RSV alleviated obesity and NAFLD, while coadministration of both products further enhanced the efficacy. These data suggested that combined prebiotic RSV and probiotic B. longum would be a potential candidate or adjuvant for the treatment of obesity and NAFLD.

The effects of resveratrol on lipid profiles and liver enzymes in patients with metabolic syndrome and related disorders: a systematic review and meta-analysis of randomized controlled trials

Background

There are current trials investigating the effect of resveratrol supplementation on lipid profiles and liver enzymes among patients with metabolic syndrome (MetS) and related disorders; however, their findings are controversial. This systematic review and meta-analysis were aimed to determine the effects of resveratrol supplementation on lipid profiles and liver enzymes among patients with MetS and related disorders.

Methods

We performed a comprehensive search of the following online databases up to November 2018: Cochrane Library, PubMed, Embase, and Web of Science. The relevant articles were assessed for quality of studies using the Cochrane risk of bias tool.

Results

Out of 2459 citations, 31 articles were appropriate for including to the current meta-analysis. The pooled results indicated that resveratrol use significantly decreased total cholesterol [weighted mean difference (WMD) = − 7.65 mg/dL; 95% CI, − 12.93, − 2.37; P < 0.01; I²: 83.4%] and increased gamma-glutamyl transferase (GGT) concentrations (WMD = 1.76 U/l; 95% CI, 0.58, 2.94; P < 0.01; I²: 20.1%). We found no significant effect of resveratrol supplementation on triglycerides (WMD = − 5.84 mg/dL; 95% CI, − 12.68, 1.00; P = 0.09; I²: 66.8%), LDL- (WMD = -2.90 mg/dL; 95% CI, − 10.88, 5.09; P = 0.47; I²: 96.0%), HDL-cholesterol (WMD = 0.49 mg/dL; 95% CI, − 0.80, 1.78; P = 0.45; I²: 74.0%), alanine aminotransferase (ALT) (WMD = -0.14 U/l; 95% CI, − 3.69, 3.41; P = 0.93; I²: 79.6%), and aspartate aminotransferase (AST) (WMD = -0.34 U/l; 95% CI, − 2.94, 2.27; P = 0.80; I²: 88.0%) concentrations.

Conclusions

This meta-analysis demonstrated that resveratrol supplementation among patients with MetS and related disorders significantly reduced total cholesterol and increased GGT concentrations, but did not affect triglycerides, LDL-, HDL-cholesterol, ALT, and AST concentrations. This data suggests that resveratrol may have a potential cardio-protective effect in patients with MetS and related disorders.

Herbal medicines for the liver: from bench to bedside

The liver is one of the most complex organs of the human body and is involved in various metabolic processes. Due to its anatomical proximity to the digestive tract, its blood flow, and its contribution to the detoxification process, the liver is susceptible to a wide variety of disorders. Hepatic diseases can be caused by alcoholism, viral infections, malnutrition and xenobiotics, which result in a high frequency of patients with liver disease and subsequent increase in the number of deaths from these diseases, for which adequate treatments are not yet available. Therefore, the search for new alternatives to treat these liver conditions is mandatory. In recent decades, there has been an increase in interest in medicinal herbs due to their safety and hepatoprotective properties that arise from their anti-inflammatory, antioxidant, antifibrotic, antiviral, immunomodulatory and anticancer properties. Epidemiological and clinical studies have shown that the consumption of these compounds is associated with a decrease in the risk of developing liver diseases; thus, medicinal herbs have emerged as a viable option for the treatment of these hepatic pathologies. However, more basic and clinical studies are needed before reaching a final recommendation to treat human liver diseases. This review provides molecular and clinical information on some natural compounds and medicinal herbs that have hepatoprotective effects and could be useful for the treatment of hepatic disorders.

Effect of green coffee extract supplementation on serum adiponectin concentration and lipid profile in patients with non-alcoholic fatty liver disease: A randomized, controlled trial

OBJECTIVES

The current study evaluated the effects of green coffee extract (GCE) on serum lipid profile and adiponectin levels in patients with nonalcoholic fatty liver disease (NAFLD).

DESIGN

This randomized, double-blind, placebo-controlled clinical trial was conducted on NAFLD patients aged 20-60 years and body mass index (BMI) of 25-35 kg/m².

SETTING

Patients were recruited from the Bahman poly-clinic (Neyshabur, Iran) between January and June 2016.

INTERVENTIONS

The study subjects were randomly assigned to receive a daily dose of 400 mg GCE (n = 24) or placebo (n = 24) for eight weeks.

MAIN OUTCOME MEASURES

Serum liver enzyme levels, lipid profile, adiponectin concentrations, and hepatic steatosis grade were measured for all patients at baseline and the end of the trial.

RESULTS

GCE supplementation significantly reduced BMI [mean difference (MD): -0.57 and 95 % confidence interval (CI): -0.84 to -0.29, P < 0.001] and increased serum high-density lipoprotein cholesterol (MD: 7.06, 95 % CI: 0.25-13.87, P < 0.05) compared to the control group. Serum total cholesterol decreased significantly within the GCE group (MD: -13.33, 95 % CI: -26.04 to -0.61, P < 0.05). Triglyceride levels reduced significantly in GCE group compared to the placebo group (MD: -37.91; 95 % CI: -72.03 to -3.80; P = 0.03). However, this reduction was not significant when was further adjusted for mean changes in BMI and daily energy intake (MD: -23.43; 95 % CI: -70.92 to 24.06; P = 0.32). Hepatic steatosis grade, liver enzymes, and adiponectin levels did not show significant differences between the two groups after the intervention.

CONCLUSIONS

GCE supplementation improved serum lipid profile and BMI in individuals with NAFLD. GCE may be useful in controlling NAFLD risk factors.

Therapeutic effect of resveratrol supplementation on oxidative stress: a systematic review and meta-analysis of randomised controlled trials

Background

Resveratrol is a naturally occurring polyphenol compound mainly found in grapes and red wine. The evidence has suggested that resveratrol has an antioxidant effect. However, the results are inconsistent and inconclusive. Thus, we conducted a systematic review and meta-analysis to evaluate the effect of resveratrol supplementation on markers of oxidative stress.

Methods

We searched PubMed, ISI Web of Science, EMBASE, Scopus and the Cochrane library up to December 2018 to identify randomised controlled trials (RCTs) assessing resveratrol supplementation effects on oxidative markers. Heterogeneity, publication bias, risk of bias and subgroup analysis were analysed. This meta-analysis was conducted in accordance with the guidelines of the Preferred ReportingItems for Systematic Reviews and Meta-Analysis (PRISMA).

Results

Meta-analysis of data from 12 RCTs did not support significant effect of resveratrol supplementation on circulating levels of superoxide dismutase (SOD) (standardized mean difference (SMD) (1.12), (95% CI −0.91 to 3.1), p=0.28), catalase (CAT) (SMD (−0.07), (95% CI −1.4 to 1.3), p=0.92) and glutathione peroxidase (GPx) (SMD (−0.76), (95% CI −2.56 to 1.04), p=0.40). Although, resveratrol supplementation increased significantly circulating total antioxidant capacity (TAC) concentrations (SMD (0.52), (95% CI −0.02 to 1.07), p=0.05). Severe heterogeneity was observed between studies, and no obvious publication bias was observed in included RCTs.

Conclusion

Collectively, our findings of available RCTs did no show any benefit of resveratrol supplementation on SOD, CAT and GPx except for TAC. Well-designed RCTs are necessary to confirm these results.

The effects of resveratrol on metabolic status in patients with type 2 diabetes mellitus and coronary heart disease

This study was performed to investigate the effects of resveratrol on metabolic status in patients with type 2 diabetes mellitus (T2DM) and coronary heart disease (CHD). This randomized, double-blind, placebo-controlled trial was performed with 56 patients having T2DM and CHD. The patients were randomly divided into two groups to receive either 500 mg resveratrol per day (n = 28) or placebo (n = 28) for 4 weeks. Resveratrol reduced fasting glucose (β-10.04 mg dL^-1; 95% CI, -18.23, -1.86; P = 0.01), insulin (β-1.09 μIU mL^-1; 95% CI, -1.93, -0.24; P = 0.01) and insulin resistance (β-0.48; 95% CI, -0.76, -0.21; P = 0.001) and significantly increased insulin sensitivity (β 0.006; 95% CI, 0.001, 0.01; P = 0.02) when compared with the placebo. Resveratrol also significantly increased HDL-cholesterol levels (β 3.38 mg dL^-1; 95% CI, 1.72, 5.05; P < 0.001) and significantly decreased the total-/HDL-cholesterol ratio (β-0.36; 95% CI, -0.59, -0.13; P = 0.002) when compared with the placebo. Additionally, resveratrol caused a significant increase in total antioxidant capacity (TAC) (β 58.88 mmol L^-1; 95% CI, 17.33, 100.44; P = 0.006) and a significant reduction in malondialdehyde (MDA) levels (β-0.21 μmol L^-1; 95% CI, -0.41, -0.005; P = 0.04) when compared with the placebo. Resveratrol upregulated PPAR-γ (P = 0.01) and sirtuin 1 (SIRT1) (P = 0.01) in the peripheral blood mononuclear cells (PBMCs) of T2DM patients with CHD. Resveratrol supplementation did not have any effect on inflammatory markers. Four-week supplementation of resveratrol in patients with T2DM and CHD had beneficial effects on glycemic control, HDL-cholesterol levels, the total-/HDL-cholesterol ratio, TAC and MDA levels. Resveratrol also upregulated PPAR-γ and SIRT1 in the PBMCs of T2DM patients with CHD.

Effects of resveratrol on VEGF & HIF1 genes expression in granulosa cells in the angiogenesis pathway and laboratory parameters of polycystic ovary syndrome: a triple-blind randomized clinical trial

OBJECTIVES

Management options for PCOS, as the most prevalent endocrine disorder in women of reproductive age, using natural supplements have a high priority for physicians, especially based on the etiological pathways. Therefore, this study was conducted to describe the effect of resveratrol on the angiogenesis pathway, for management of PCOS through assessing VEGF, HIF1 gene expression, and laboratory parameters.

METHODS

In this triple-blind RCT, PCOS was confirmed in ICSI candidates based on the Rotterdam criteria. Sixty-two patients that met the inclusion criteria were randomly assigned to two groups. All patients took resveratrol 800 mg/day or placebo for 40 days orally from the beginning of their previous menstruation cycle until the oocyte retrieval day. The serum levels of different hormones were measured, and the expression of HIF1 & VEGF genes was quantified by real-time PCR.

RESULTS

As for the laboratory hormone assay in 61 PCOS patients, a significant mean difference was seen in the FSH, LH, TSH, and testosterone between the two groups (P < 0.05). The results showed a reduction in the expression of VEGF & HIF1 genes under the effect of resveratrol in the granulosa cells (P = 0.0001). The number of mature oocytes, cleavage rate, fertilization rate, and fertility rate were not significantly different between the two groups (P > 0.05), but the high-quality oocyte rate and high-quality embryo rate were higher in the resveratrol group (P < 0.05).

CONCLUSIONS

Based on the results, resveratrol may improve some outcomes of PCOS patients, probably through changing the serum levels of some sex hormones and expression of VEGF & HIF1 genes in the angiogenesis pathway of granulosa cells.

Resveratrol Enhances Apoptotic and Oxidant Effects of Paclitaxel through TRPM2 Channel Activation in DBTRG Glioblastoma Cells

Numerous studies have reported a strong association between increased production of reactive oxygen species (ROS) and the pathobiology of several diseases, and cancer in particular. Therefore, manipulation of cellular oxidative stress levels represents an important therapeutic target. Recently, resveratrol (RESV), a naturally occurring phytochemical, has been shown to sensitize several cell lines to the anticancer effects of other chemotherapeutic agents, including paclitaxel (PAX). However, the molecular mechanisms of action of RESV through oxidative sensitive TRPM2 channel activation remain unclear. The aim of this study was to evaluate the effect of combination therapy of RESV and PAX on activation of TRPM2 in DBTRG glioblastoma cells. DBTRG cells were divided into four treatment groups: control, RESV (50 μM), PAX (50 μM), and PAX + RESV for 24 hours. Our data shows that markers for apoptosis, mitochondrial membrane depolarization and mitochondrial function, intracellular steady-state ROS levels, caspase 3 activity, TRPM2 current density, and Ca²⁺ florescence intensity were significantly increased in DBTRG cells following treatment with PAX and RESV, respectively, although cell viability was also decreased by these treatments. These biochemical markers were further increased to favor the anticancer effects of PAX in DBTRG cells in combination with RESV. The PAX and RESV-mediated increase in current density and Ca²⁺ florescence intensity was decreased with a TRPM2 blocker. This suggests that for this combination therapy to have a substantial effect on apoptosis and cell viability, the TRPM2 channel must be stimulated.