A comprehensive insight into the potential effects of resveratrol supplementation on SIRT-1: A systematic review

Impact of Resveratrol Supplementation on Human Sirtuin 1: A Grading of Recommendations Assessment, Development and Evaluation-Assessed Systematic Review and Dose-Response Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Resveratrol, a natural polyphenol compound, possesses anti-aging, antitumor, and vascular protective properties. These attributes are believed to stem from its influence on Sirtuin 1 (Sirt1), a member of the human Sirtuin family and a nicotinamide adenine dinucleotide-dependent histone deacetylase.

OBJECTIVE

The aim of this study was to quantitatively investigate the impact of resveratrol supplementation on Sirt1 levels in adults by conducting a systematic review and meta-analysis of randomized controlled trials (RCTs) involving resveratrol supplementation.

METHODS

This Grading of Recommendations Assessment, Development and Evaluation-assessed systematic review involved a comprehensive search of PubMed, Embase, MEDLINE, Scopus, Web of Science, Cochrane Central Register of Controlled Trials, and Google Scholar databases using related keywords and was conducted from March 14, 2024, to April 15, 2024, to identify all RCTs investigating resveratrol's effects on Sirt1. Effect sizes were quantified as mean differences (MDs) or standardized mean differences (SMDs), with standard deviations of outcomes. An overall effect estimate was derived using a random-effects model when 2 or more studies reported similar outcomes. Statistical heterogeneity was assessed through the calculation of I2 statistics. In addition, a dose-response analysis was performed to assess potential dose-response relationships. Risk of bias was assessed using the Cochrane risk-of-bias tool for RCTs (RoB 2). Publication bias was evaluated using Begg's test and a meta-regression using the year of publication as a moderator.

RESULTS

Eleven RCTs examining the effects of resveratrol on Sirt1 gene expression (4 RCTs), protein expression (5 RCTs), and serum levels (3 RCTs) were included in the meta-analysis. The results showed no significant impact of resveratrol on Sirt1 gene expression (SMD = 0.05; 95% CI -0.24 to 0.344; P = .73), protein expression (SMD = 0.3; 95% CI -0.15 to 0.77; P = .18), or serum levels (MD = -0.04; 95% CI -0.235 to 0.16; P = .7). However, subgroup analyses suggested a significant increase in Sirt1 gene expression in studies with an intervention duration of <12 weeks and evaluating blood tissue. Furthermore, the impact of resveratrol on Sirt1 appeared to be influenced by the dosage regimen, with a significant effect for intervention duration.

CONCLUSIONS

Study results indicate that resveratrol supplementation does not significantly influence human Sirt1 based on the overall meta-analysis. However, the dose-response analysis suggests that the effect of resveratrol on Sirt1 depends on the dosage regimen.

Caloric restriction mimetics: Pinostilbene versus resveratrol regarding SIRT1 and SIRT6 interaction

PURPOSE

Caloric restriction (CR), the permanent or periodic reduction of caloric intake, is a dietary strategy that promotes longevity and healthspan, yielding multiple beneficial effects, such as improved insulin sensitivity and mitochondrial function, decreased body weight, and mitigation of cardiometabolic risk factors. The purpose of our study was the in silico and in vitro assessment of the effects exerted by pinostilbene on SIRT1 and SIRT6 compared to those of resveratrol, a known activator of these enzymes.

MATERIALS AND METHODS

Molecular docking was carried out to determine the interactions with SIRT1 and SIRT6 and, further, the effect of pinostilbene on their activity was tested in vitro to evaluate if it parallels resveratrol's effects regarding SIRT activation.

RESULTS

Molecular docking indicates that resveratrol and pinostilbene bind similarly to SIRT6, while pinostilbene may be able to activate SIRT1 more efficiently than resveratrol. In vitro activity assays showed that while both resveratrol and pinostilbene activate SIRT1 and SIRT6, the concentration-dependent effects differ. For resveratrol, a greater effect was observed at the medium concentration (25 ​μM), whereas pinostilbene showed a more pronounced activation at the lowest concentration (5 ​μM).

CONCLUSIONS

Our results offer a glimpse into the structural features and interactions of pinostilbene and resveratrol with SIRT1 and SIRT6, contributing to understanding their potential roles in various cellular processes regulated by SIRT.

The SIRT-1/Nrf2/HO-1 axis: Guardians of neuronal health in neurological disorders

SIRT1 (Sirtuin 1) is a NAD+-dependent deacetylase that functions through nucleoplasmic transfer and is present in nearly all mammalian tissues. SIRT1 is believed to deacetylate its protein substrates, resulting in neuroprotective actions, including reduced oxidative stress and inflammation, increased autophagy, increased nerve growth factors, and preserved neuronal integrity in aging or neurological disease. Nrf2 is a transcription factor that regulates the genes responsible for oxidative stress response and substance detoxification. The activation of Nrf2 guards cells against oxidative damage, inflammation, and carcinogenic stimuli. Several neurological abnormalities and inflammatory disorders have been associated with variations in Nrf2 activation caused by either pharmacological or genetic factors. Recent evidence indicates that Nrf2 is at the center of a complex cellular regulatory network, establishing it as a transcription factor with genuine pleiotropy. HO-1 is most likely a component of a defense mechanism in cells under stress, as it provides negative feedback for cell activation and mediator synthesis. This mediator is upregulated by Nrf2, nitric oxide (NO), and other factors in various inflammatory states. HO-1 or its metabolites, such as CO, may mitigate inflammation by modulating signal transduction pathways. Neurological diseases may be effectively treated by modulating the activity of HO-1. Multiple studies have demonstrated that SIRT1 and Nrf2 share an important connection. SIRT1 enhances Nrf2, activates HO-1, protects against oxidative injury, and decreases neuronal death. This has been associated with numerous neurodegenerative and neuropsychiatric disorders. Therefore, activating the SIRT1/Nrf2/HO-1 pathway may help treat various neurological disorders. This review focuses on the current understanding of the SIRT1 and Nrf2/HO-1 neuroprotective processes and the potential therapeutic applications of their target activators in neurodegenerative and neuropsychiatric disorders.

Antioxidant Effect of a Plant-Derived Extracellular Vesicles' Mix on Human Skin Fibroblasts: Induction of a Reparative Process

Plant-Derived Extracellular Vesicles extracellular vesicles (PDEVs) from organic agriculture (without the use of pesticides and microbicides) contain high levels of antioxidants. Organic PDEVs have shown an increased antioxidant power compared to PDEVs from single plants, suggesting a synergistic effect of the bioactives constitutively expressed in the PDEVs from single fruits. With this study, we wanted to investigate the beneficial effects of a mix of PDEVs on human skin cells. We found detectable levels of citric acid, ascorbic acid, glutathione, catalase, and SOD in a mix of PDEVs deriving from five different fruits (grape, red orange, papaya, pomegranate, and tangerine). We then treated H2O2-conditioned fibroblasts with the mix of PDEVs. The results showed that the PDEVs' mixture reverted the H2O2-induced redox imbalance, restoring mitochondrial homeostasis, with a strong reduction of mitochondrial anion superoxide and an increase in sirtuin levels. The antioxidant action was consistent with wound repair on a lesion produced in a fibroblast's monolayer. This result was consistent with an increased level of vimentin and matrix metalloproteinase-9, whose expression is directly related to the efficiency of the reparative processes. These data support a beneficial role of PDEVs in both preventing and treating skin injuries through their potent antioxidant and reparative activities.

Exploring epigenetic strategies for the treatment of osteoporosis

The worldwide trend toward an aging population has resulted in a higher incidence of chronic conditions, such as osteoporosis. Osteoporosis, a prevalent skeletal disorder characterized by decreased bone mass and increased fracture risk, encompasses primary and secondary forms, each with distinct etiologies. Mechanistically, osteoporosis involves an imbalance between bone resorption by osteoclasts and bone formation by osteoblasts. Current pharmacological interventions for osteoporosis, such as bisphosphonates, denosumab, and teriparatide, aim to modulate bone turnover and preserve bone density. Hormone replacement therapy and lifestyle modifications are also recommended to manage the condition. While current medications offer therapeutic options, they are not devoid of limitations. Recent studies have highlighted the importance of epigenetic mechanisms, including DNA methylation and histone modifications, in regulating gene expression during bone remodeling. The use of epigenetic drugs, or epidrugs, to target these mechanisms offers a promising avenue for therapeutic intervention in osteoporosis. In this review, we comprehensively examine the recent advancements in the application of epidrugs for treating osteoporosis.

Evaluating the Stability of a Novel Nutraceutical Formulation Combining Probiotic Limosilactobacillus fermentum 296, Quercetin, and Resveratrol Under Different Storage Conditions

This study evaluated the stability of a novel nutraceutical formulation composed of the probiotic Limosilactobacillus fermentum 296, quercetin (QUE), and resveratrol (RES) (LFQR) under different storage conditions. The effects of different relative humidities (RH; 11, 22, and 33%) and storage temperatures (refrigeration temperature -4 °C and room temperature -25 °C) on the stability of LFQR were evaluated through the determination of thermal stability, viable cell counts, bacterial physiological status, antioxidant capacity, and contents of QUE and RES during long-term storage. RH did not affect endothermic reactions and mass reduction in LFQR. After a 15-day-humidification period, L. fermentum 296 had higher viable cell counts in LFQR under refrigeration temperature storage when compared to room temperature storage regardless of the RH. The physiological status of L. fermentum 296 in LFQR was overall similar during 90 days of storage (11% RH) under refrigeration and room temperature. L. fermentum 296 had the highest viable cell counts (> 6 log CFU/g) in LFQR up to day 90 of refrigeration storage (11% RH). LFQR kept high contents of QUE and RES and maintained antioxidant capacity during 90 days of storage under refrigeration and room temperature. The results showed that the higher stability and functionality of LFQR during long-term storage should be guaranteed under 11% RH and refrigeration temperature.

Antioxidants and phytochemicals - a scoping review for Nordic Nutrition Recommendations 2023

Antioxidants are a collection of substances that may prevent or delay the oxidation of cellular components. The antioxidant defense system includes both endogenously produced antioxidants and dietary antioxidants. The consumption of dietary antioxidants has long been speculated to be important for the defense against cellular oxidation, inflammation, and other disease-related processes. In addition to the well-known dietary antioxidants, such as vitamin C, vitamin E, β-carotene, and selenium, whole plants and plant-products contain numerous compounds, called phytochemicals, with antioxidant properties. These phytochemicals are potentially important modulators of oxidative stress and have been linked to health beneficial effects. However, the mechanisms underlying these potential health beneficial effects are not well understood. Foods containing high levels of phytochemicals with antioxidant properties include berries, fruits, vegetables, whole grains, and nuts and seeds. The aim of this scoping review is to describe the evidence of the role of specific antioxidants and phytochemicals, but not foods rich in these substances, for health outcomes. Based on a literature search from 2011 to March 2022, we identified eight meta-analyses related to the current topic. These studies include evidence of the effect of resveratrol (present mainly in berries, grapes, and peanuts) on health outcomes related to cardiometabolic risk, blood pressure, obesity, oxidative stress, adipokines, inflammation, and bone quality. In summary, resveratrol did elicit several health beneficial effects. However, the magnitude of effects was low, and whether the effects are related to the redox properties of resveratrol is not known. Even though there is a large body of evidence linking a plant-based diet rich in antioxidants and phytochemicals to beneficial health effects, the role of specific antioxidants and phytochemicals is still unclear.

Why Is Longevity Still a Scientific Mystery? Sirtuins-Past, Present and Future

The sirtuin system consists of seven highly conserved regulatory enzymes responsible for metabolism, antioxidant protection, and cell cycle regulation. The great interest in sirtuins is associated with the potential impact on life extension. This article summarizes the latest research on the activity of sirtuins and their role in the aging process. The effects of compounds that modulate the activity of sirtuins were discussed, and in numerous studies, their effectiveness was demonstrated. Attention was paid to the role of a caloric restriction and the risks associated with the influence of careless sirtuin modulation on the organism. It has been shown that low modulators' bioavailability/retention time is a crucial problem for optimal regulation of the studied pathways. Therefore, a detailed understanding of the modulator structure and potential reactivity with sirtuins in silico studies should precede in vitro and in vivo experiments. The latest achievements in nanobiotechnology make it possible to create promising molecules, but many of them remain in the sphere of plans and concepts. It seems that solving the mystery of longevity will have to wait for new scientific discoveries.

Implications of Resveratrol in Obesity and Insulin Resistance: A State-of-the-Art Review

Background: Resveratrol is a polyphenol chemical that naturally occurs in many plant-based dietary products, most notably, red wine. Discovered in 1939, widespread interest in the potential health benefits of resveratrol emerged in the 1970s in response to epidemiological data on the cardioprotective effects of wine. Objective: To explore the background of resveratrol (including its origins, stability, and metabolism), the metabolic effects of resveratrol and its mechanisms of action, and a potential future role of dietary resveratrol in the lifestyle management of obesity. Data sources: We performed a narrative review, based on relevant articles written in English from a Pubmed search, using the following search terms: “resveratrol”, “obesity”, “Diabetes Mellitus”, and “insulin sensitivity”. Results: Following its ingestion, resveratrol undergoes extensive metabolism. This includes conjugation (with sulfate and glucuronate) within enterocytes, hydrolyzation and reduction within the gut through the action of the microbiota (with the formation of metabolites such as dihydroresveratrol), and enterohepatic circulation via the bile. Ex vivo studies on adipose tissue reveal that resveratrol inhibits adipogenesis and prevents the accumulation of triglycerides through effects on the expression of Peroxisome Proliferator-activated Receptor γ (PPARγ) and sirtuin 1, respectively. Furthermore, resveratrol induces anti-inflammatory effects, supported by data from animal-based studies. Limited data from human-based studies reveal that resveratrol improves insulin sensitivity and fasting glucose levels in patients with Type 2 Diabetes Mellitus and may improve inflammatory status in human obesity. Although numerous mechanisms may underlie the metabolic benefits of resveratrol, evidence supports a role in its interaction with the gut microbiota and modulation of protein targets, including sirtuins and proteins related to nitric oxide, insulin, and nuclear hormone receptors (such as PPARγ). Conclusions: Despite much interest, there remain important unanswered questions regarding its optimal dosage (and how this may differ between and within individuals), and possible benefits within the general population, including the potential for weight-loss and improved metabolic function. Future studies should properly address these important questions before we can advocate the widespread adoption of dietary resveratrol supplementation.