Short-Term Oral Quercetin Supplementation Improves Post-exercise Insulin Sensitivity, Antioxidant Capacity and Enhances Subsequent Cycling Time to Exhaustion in Healthy Adults: A Pilot Study

Quercetin-loaded PEGylated liposomes alleviate testicular dysfunction in alloxan-induced diabetic rats: The role of Kisspeptin/Neurokinin B/Dynorphin pathway

Diabetes mellitus (DM) is a chronic metabolic disorder that can lead to serious complications, including testicular dysfunction. This dysfunction is considered a significant cause of male infertility. Quercetin (Que), a naturally existing flavonoid with versatile biological functions, has limited water solubility and low bioavailability. The current study was designed to develop a bioavailable formulation of Que. via encapsulating it in PEGylated liposomes (Que-PEG-Lip) and determine whether this formulation is effective in the treatment of alloxan-induced testicular injury via targeting Kisspeptin/Neurokinin B/Dynorphin/steroidogenesis signaling pathway. Thirty-two male Sprague Dawley rats were randomly divided into four groups: Control, alloxan-induced diabetes with testicular dysfunction (ALX), ALX + metformin (MET) and ALX + Que-PEG-Lip. The results showed that treatment of ALX group with Que-PEG-Lip significantly improved the alteration of glycemic index, serum reproductive hormones, testicular antioxidant status, testicular Kiss-1, androgen receptor (AR), and proliferation marker protein (ki67) immunoexpression in compared to ALX group. Moreover, the treatment of ALX group with Que-PEG-Lip regulated the Kisspeptin/Neurokinin B/Dynorphin/steroidogenesis pathway gene expression. Interestingly, the outcomes of the molecular docking analysis revealed a strong agonistic effect of Que. on the kisspeptin, neurokinin, and dynorphin receptors. In conclusion, Que-PEG-Lip mitigated the testicular dysfunction in alloxan-induced diabetic rats via regulation of hypothalamic-pituitary-gonadal axis signaling pathway and alleviation the testicular oxidative stress.

Nutritional Strategies to Improve Post-exercise Recovery and Subsequent Exercise Performance: A Narrative Review

Post-exercise recovery strategies influence the body's ability to restore physiological homeostasis, replenish energy stores, repair muscle damage, and promote desired adaptations, which improve exercise performance. This narrative review examines the impact of nutritional strategies commonly used for enhancing recovery and subsequent exercise performance, particularly when athletes face short recovery periods. Carbohydrate ingestion is essential for glycogen replenishment, especially within the initial hours post-exercise, with its impact dependent on the types, timing, and amount. Protein is essential for accelerating muscle recovery and achieving a positive nitrogen balance, depending on the type and dosage. The co-ingestion of carbohydrates with proteins or fats is explored for its role in maximizing glycogen resynthesis and muscle repair, with evidence supporting the addition of protein to suboptimal carbohydrate intake for enhanced recovery. Moreover, this review addresses the potential benefits of creatine and caffeine co-ingestion for accelerating glycogen synthesis and improving subsequent performance. Hydration strategies, including the use of milk-based beverages and electrolyte solutions, are also discussed, emphasizing their importance in maintaining fluid balance and optimizing recovery. This review also highlights the emerging role of micronutrients such as omega-3 fatty acids, antioxidants, and sodium bicarbonate in reducing muscle damage and improving acid-base balance. Evidence supports the tailored use of these nutritional strategies, particularly for athletes managing tight competition/training schedules. Future research should focus on refining individualized approaches for recovery and investigating the impact of novel supplements on subsequent performance.

Polyphenols and post-exercise muscle damage: a comprehensive review of literature

Recent research highlights the significant role of polyphenols in alleviating post-exercise muscle damage, thus positioning them as a valuable nutritional strategy for athletes and fitness enthusiasts. Polyphenols, naturally occurring bioactive compounds abundant in fruits, vegetables, tea, wine, and other plant-based foods, are recognized for their potent antioxidant and anti-inflammatory properties. This dual mechanism is critical for combating oxidative stress and inflammation-two factors that intensify during vigorous physical activity and contribute to muscle soreness and damage. Among various polyphenols, compounds like quercetin have particularly emerged as effective agents for promoting muscle recovery and enhancing exercise performance. These protective effects are facilitated through several mechanisms, including the modulation of inflammatory pathways, acceleration of muscle repair processes, and enhancement of mitochondrial function, all of which bolster overall muscle health. As ongoing studies yield deeper insights, the potential of polyphenols to enhance athletic performance and overall health will become increasingly substantiated, leading towards their strategic incorporation into exercise nutrition protocols. Therefore, we reviewed relevant studies in order to show how efficient polyphenols can be in reducing muscle fatigue and damage and what are the exact mechanisms.

Effects of Quercetin and Citrulline on Nitric Oxide Metabolites and Antioxidant Biomarkers in Trained Cyclists

BACKGROUND

Quercetin (QCT) and citrulline (CIT) have been independently associated with improved antioxidant capacity and nitric oxide (NO) production, potentially enhancing cardiovascular function and exercise performance. This study aimed to evaluate the combined and independent effects of QCT and CIT supplementation on NO metabolites and antioxidant biomarkers in 50 trained cyclists undergoing a 20 km cycling time trial (TT).

METHODS

In a randomized, double-blind, placebo-controlled design, forty-two male and eight female trained cyclists were assigned to QCT + CIT, QCT, CIT, or placebo (PL) groups. Supplements were consumed twice daily for 28 days. Biochemical assessments included NO metabolites (nitrate/nitrite), ferric reducing antioxidant power (FRAP), superoxide dismutase (SOD) activity, and antioxidant capacity, measured pre- and post-TT.

RESULTS

NO metabolites were significantly elevated post-supplementation (p = 0.03); however, no significant interaction effects were observed for NO metabolites, FRAP, SOD, or antioxidant capacity across the groups (p > 0.05). Post-hoc analyses revealed that QCT significantly reduced FRAP concentrations compared to PL (p = 0.01), while no significant changes in SOD or antioxidant capacity were found across any groups.

CONCLUSIONS

These findings suggest that combined and independent QCT and CIT supplementation did not significantly improve these biomarkers, suggesting that baseline training adaptations, supplementation timing, and individual variability may influence the efficacy of these compounds in enhancing exercise performance and oxidative stress markers. The ergogenic efficacy of QCT + CIT on antioxidant-related markers remains inconclusive.

Health Benefits and Future Research of Phytochemicals: A Literature Review

Phytochemicals are nonnutritive substances found in plant foods that contribute significantly to the flavor and color of foods. These substances are usually classified as polyphenols, terpenes, sulfur-containing compounds, nitrogen-containing compounds, and others. Numerous studies over the last decades have demonstrated these substances play an immeasurable role in physiological regulation, health care, and disease prevention through their actions in antioxidation, anti-inflammation, antiaging, antivirus, anticancer, antithrombosis, lipid profile regulation, cardiovascular protection, neuroprotection, immunity regulation, and improvement of metabolic functions. This article reviews the chemistry and biochemistry of phytochemicals, their classification and chemical structure, occurrence and biosynthesis in plants, and biological activities and implications for human health and various diseases. The discussions are focused on the most recent important advances in these phytochemical researches. In addition, some future research directions of phytochemicals are set forth regarding dose-response, their mechanism and targets, interactions with gut microbiota, and impact on human health and different stages of chronic diseases.

Antifatigue effect of okara protein hydrolysate supplementation during cycling exercise in men: a pre-post uncontrolled pilot study

BACKGROUND

Prolonged exercise usually leads to exercise fatigue, which has a negative short-term impact on exercise performance and metabolic rate; thus, fatigue needs to be resolved. Okara is a protein-rich residue of soy processing. Enzyme hydrolysis is known to increase the content of branched-chain amino acids (BCAAs), which have been reported to confer benefits for exercise. The purpose of this study was to investigate the antifatigue effect of okara protein hydrolysate (OPH) on cycling exercise.

METHODS

A total of 16 male participants who habitually exercised (2 times or more per week and without participation in athletic contests) were instructed to receive 11.74 g of OPH once a day. They then completed two intense cycling exercise challenges before and after four weeks of supplementation. Exercise time and blood markers related to fatigue and energy metabolism were measured.

RESULTS

The results showed that the time to exhaustion significantly increased after the treatment. The levels of lactate during exercise and at the end of exercise were significantly lower after treatment than before. Additionally, postexercise insulin sensitivity was increased after treatment.

CONCLUSIONS

This study showed that OPH supplementation can promote endurance in exercise by decreasing the accumulation of fatigue-related metabolites during exercise and can promote energy recovery by increasing insulin function. These findings suggest that OPH has an antifatigue property.

Moringa oleifera leaf extracts improve exercise performance in young male adults: A pilot study

BACKGROUND

Moringa oleifera leaves are rich in bioactive substances.

PURPOSE

The purpose of this study was to evaluate the effects of Moringa oleifera leaf aqueous extract supplements on energy metabolism and antioxidant function in young male adults.

METHODS

Forty-four young male adults (26.3 ± 3.5 years) were randomly assigned to two groups: a supplement group (n = 23) receiving aqueous extract of Moringa oleifera leaves and a placebo group (n = 21). The supplementation period lasted for 30 days. Baseline measurements were taken at the beginning of the study, and further measurements were taken at the end of the supplementation period. Changes in upper- and lower-body strength, treadmill endurance, and certain blood biochemical parameters were evaluated.

RESULTS

After 30 days of supplementation, participants in the supplement group exhibited enhanced performance in push-ups and treadmill exhaustion tests compared to the placebo group. Levels of glucose, urea, malondialdehyde, and glutathione peroxidase activity in serum were also improved in the supplement group.

CONCLUSION

The findings suggest that Moringa oleifera leaf aqueous extracts have the potential to improve post-exercise energy metabolism and antioxidant function in young male adults.

Therapeutic potential of natural products in inflammation: underlying molecular mechanisms, clinical outcomes, technological advances, and future perspectives

Chronic inflammation is a common underlying factor in many major diseases, including heart disease, diabetes, cancer, and autoimmune disorders, and is responsible for up to 60% of all deaths worldwide. Metformin, statins, and corticosteroids, and NSAIDs (non-steroidal anti-inflammatory drugs) are often given as anti-inflammatory pharmaceuticals, however, often have even more debilitating side effects than the illness itself. The natural product-based therapy of inflammation-related diseases has no adverse effects and good beneficial results compared to substitute conventional anti-inflammatory medications. In this review article, we provide a concise overview of present pharmacological treatments, the pathophysiology of inflammation, and the signaling pathways that underlie it. In addition, we focus on the most promising natural products identified as potential anti-inflammatory therapeutic agents. Moreover, preclinical studies and clinical trials evaluating the efficacy of natural products as anti-inflammatory therapeutic agents and their pragmatic applications with promising outcomes are reviewed. In addition, the safety, side effects and technical barriers of natural products are discussed. Furthermore, we also summarized the latest technological advances in the discovery and scientific development of natural products-based medicine.

Biflavonoid quercetin protects against cyclophosphamide-induced organ toxicities via modulation of inflammatory cytokines, brain neurotransmitters, and astrocyte immunoreactivity

BACKGROUND

Cyclophosphamide use has been associated with increased oxidative stress in cells and tissues. Quercetin's antioxidative properties make it of potential benefit in such conditions of oxidative stress.

OBJECTIVE

To assess quercetin's ability to mitigate cyclophosphamide-induced organ toxicities in rats.

METHODS

Sixty rats were assigned into six groups. Groups A and D served as normal and cyclophosphamide control and were fed standard rat chow, groups B and E were fed quercetin supplemented diet (100 mg/kg of feed), while those in groups C and F were fed quercetin at 200 mg/kg of feed. Groups A-C received intraperitoneal (ip) normal saline on days 1 and 2, while D-F received ip cyclophosphamide (150 mg/kg/day on days 1 and 2). On day 21, behavioural tests were carried out, animals were sacrificed and blood samples taken. Organs were processed for histological study.

RESULTS

Quercetin reversed cyclophosphamide-induced decrease in body weight, food intake and total antioxidant capacity, and increase in lipid peroxidation (p = 0.001), It also reversed derangement in levels of liver transaminase, urea, creatinine and proinflammatory cytokines (p = 0.001). Improvement in working-memory and anxiety-related behaviours were also observed. Finally, quercetin reversed alterations in levels of acetylcholine, dopamine and brain-derived neurotropic factor (p = 0.021); while reducing serotonin levels and astrocyte immunoreactivity.

CONCLUSION

Quercetin shows significant ability to protect against cyclophosphamide-induced changes in rats.

Microalgae as a Nutraceutical Tool to Antagonize the Impairment of Redox Status Induced by SNPs: Implications on Insulin Resistance

Microalgae represent a growing innovative source of nutraceuticals such as carotenoids and phenolic compound which are naturally present within these single-celled organisms or can be induced in response to specific growth conditions. The presence of the unfavourable allelic variant in genes involved in the control of oxidative stress, due to one or more SNPs in gene encoding protein involved in the regulation of redox balance, can lead to pathological conditions such as insulin resistance, which, in turn, is directly involved in the pathogenesis of type 2 diabetes mellitus. In this review we provide an overview of the main SNPs in antioxidant genes involved in the promotion of insulin resistance with a focus on the potential role of microalgae-derived antioxidant molecules as novel nutritional tools to mitigate oxidative stress and improve insulin sensitivity.

Quercetin Abates Aluminum Trioxide Nanoparticles and Lead Acetate Induced Altered Sperm Quality, Testicular Oxidative Damage, and Sexual Hormones Disruption in Male Rats

This study examined the effects of exposure to lead acetate (PbAc) and/or aluminum trioxide nanoparticles (Al2O3NPs) on testicular function. Additionally, the probable reproprotective effects of quercetin (QTN) against Al2O3NPs and PbAc co-exposure in male Sprague Dawely rats were assessed. Al2O3NPs (100 mg/kg b.wt.), PbAc (50 mg/kg b.wt.), and QTN (20 mg/kg b.wt.) were orally administered for 60 days. Then, spermiogram, histopathological examinations of the testis and accessory glands, and immunohistochemical detection of androgen receptors (AR) and tumor necrotic factor alpha (TNF-α) were achieved. Moreover, serum levels of male sex hormones and testicular levels of antioxidant indices were estimated. The results showed that Al2O3NPs and/or PbAc caused significant sperm abnormalities, testicular oxidative stress, and histopathological changes. Furthermore, serum testosterone, LH, and FSH levels significantly decreased, while estradiol levels significantly increased. The Al2O3NPs and/or PbAc co-exposed group had more obvious disturbances. Furthermore, QTN co-administration significantly reversed the Al2O3NPs and PbAc-induced testicular histopathological alterations, reduced antioxidant defenses, and altered AR and TNF-α immune expression in testicular tissues. Conclusively, Al2O3NPs and/or PbAc evoked testicular dysfunction by inducing oxidative injury and inflammation. However, QTN oral dosing effectively mitigated the negative effects of Al2O3NPs and PbAc by suppressing oxidative stress and inflammation and improving the antioxidant defense system.