Polyphenols as Caloric Restriction Mimetics Regulating Mitochondrial Biogenesis and Mitophagy

Dietary polyphenols as geroprotective compounds: From Blue Zones to hallmarks of ageing

Following the demographic shift towards an ageing population over the past century, particularly in developed countries, the concept of healthspan has gained increasing acceptance as a key framework for understanding the drivers of healthy ageing. Accordingly, long-lived individuals, such as nonagenarians and centenarians, who remain free from chronic diseases, provide a valuable model to investigate the complex interplay of biological, genetic, and environmental factors that contribute to exceptional longevity. Although there are other longevity hotspots worldwide, five regions, known as Blue Zones, are widely recognized for their exceptionally long-lived populations. Among the various determinants of healthy ageing, the eating patterns of long-lived individuals in Blue Zones include a variety of polyphenol-rich foods, which may contribute to their healthy phenotype. A significant body of evidence suggests that polyphenols, a large family of compounds ubiquitously found in plant-based foods, may exhibit geroprotective activity by influencing underlying biological mechanisms of ageing and promoting optimal longevity. While identifying several knowledge gaps that future investigations should address, the goal of this review is to provide an overview of how specific polyphenols found in foods commonly consumed by long-lived individuals residing in the Blue Zones may mitigate the risk of age-related diseases. Additionally, we discuss how these compounds, by acting on evolutionarily conserved mechanisms associated with ageing, have the potential to modulate the intricate network of the hallmarks of ageing.

Effects of Quercetin Metabolites on Glucose-Dependent Lipid Accumulation in 3T3-L1 Adipocytes

The aim of the study was to assess the effects of quercetin metabolites (QMs) on lipid accumulation in adipocytes under high-glucose and physiological-glucose concentrations and to elucidate the mechanisms involved. 3T3-L1 mature adipocytes were exposed to a physiological glucose concentration, as a model of caloric restriction (CR), or high glucose (control), with and without QMs (quercetin-3-glucuronide [Q3G] and isorhamnetin [ISOR]). Cells were treated with Q3G (0.3 and 0.6 µmol/L) and ISOR (0.2 and 0.4 µmol/L) for 48 h. Lipid accumulation (Oil Red O staining) and Δ glucose level (HPLC) were assessed. Under high glucose, Q3G and ISOR reduced lipid accumulation (-10.8% and -10.4%; p < 0.01) and Δ glucose level (-13.6% and -14.2%; p < 0.05). Under CR, QMs increased Δ glucose level (+21.6% for Q3G and +21% for ISOR; p < 0.05). ISOR increased pAMPK levels under high glucose (+1.4-fold; p < 0.05). Under CR, Q3G and ISOR increased pAMPK (+1.4- and +1.5-fold; p < 0.05), while ISOR upregulated SIRT1 and PGC-1α (+2.3- and +1.5-fold; p < 0.05). Findings support, for the first time, the potential contribution of QMs, especially ISOR, in the regulation of lipid metabolism in vitro, possibly via AMPK activation. Further studies, including in vivo, are encouraged to strengthen evidence of the mechanisms observed.

Intermittent fasting applied in combination with astaxanthin alleviates D-galactose-induced aging in rats: Comparison in oxidative stress, immune response, and metabolomics

Effective anti-aging strategies involving dietary restriction and antioxidant supplementation are gaining increasing research attention, while the health effects of their combined intervention are rarely reported. In this study, for the first time, we investigated the anti-aging effects and underlying mechanisms of intermittent fasting (IF), astaxanthin (AX), and their combination in D-galactose-induced aging rats. Our results demonstrated that these three treatments effectively inhibited malondialdehyde levels and improved the activity of endogenous antioxidant enzymes in the brain, liver, and serum of aging rats. Simultaneously, the combination of IF and AX had a synergistic effect on the recovery of brain mitochondrial injury as evidenced by permeability transition pore openness, membrane potential, respiratory chain complex enzyme activity, and cortical and hippocampal lesions. Notably, the combination significantly increased the levels of Immunoglobulin M (55.66 ± 3.23%), immunoglobulin G (34.41 ± 2.65%), and IL-2 (23.49 ± 1.78%) compared with the model group. Moreover, AX reduced the accumulation of pro-inflammatory factor IL-6 (23.06 ± 2.02%), while the combination induced more remarkable reduction in the accumulation of IL-1β (35.92 ± 3.06%) in the serum. Considering the serum metabolomics analysis, we hypothesized that IF and AX played a positive role in the regulation of the nervous system, which was associated with the differential metabolites lysope 16:0, N-Acety-L-tyrosine, and L-Alanyl-L-Lysine. This research reveals that the combination therapy provided synergistic anti-aging efficacy by enhancing resistance to oxidative stress, ameliorating mitochondrial dysfunction, and restoring the immune system. These findings might have significant implications for further studies on the exploration of effective anti-aging therapy.

Interplay Between Polyphenols and Autophagy: Insights From an Aging Perspective

The relationship between polyphenols and autophagy, particularly in the context of aging, presents a promising avenue for therapeutic interventions in age-related diseases. A decline in autophagy is associated with aging-related affections, and an increasing number of studies suggest that this enhancement is linked to cellular resilience and longevity. This review delves into the multifaceted roles of autophagy in cellular homeostasis and the potential of polyphenols to modulate autophagic pathways. We revised the most updated literature regarding the modulatory effects of polyphenols on autophagy in cardiovascular, liver, and kidney diseases, highlighting their therapeutic potential. We highlight the role of polyphenols as modulators of autophagy to combat age-related diseases, thus contributing to improving the quality of life in aging populations. A better understanding of the interplay of autophagy between autophagy and polyphenols will help pave the way for future research and clinical applications in the field of longevity medicine.

HINT1 suppression protects against age-related cardiac dysfunction by enhancing mitochondrial biogenesis

OBJECTIVE

Cardiac function declines with age, impairing exercise tolerance and negatively impacting healthy aging. However, mechanisms driving age-related declines in cardiac function are not fully understood.

METHODS

We examined mechanisms underlying age-related cardiac dysfunction using 3- and 24-month-old wild-type mice fed ad libitum or 24-month-old wild-type mice subjected to 70% calorie restriction (CR) starting at 2-month-old. In addition, cardiac aging phenotypes and mitochondrial biogenesis were also analyzed in 25-month-old cardiac-specific Hint1 knockout mice, 24-month-old CAG-Caren Tg mice, and 24-month-old wild-type mice injected with AAV6-Caren.

RESULTS

We observed inactivation of mitochondrial biogenesis in hearts of aged mice. We also showed that activity of the BAF chromatin remodeling complex is repressed by HINT1, whose expression in heart increases with age, leading to decreased transcription of Tfam, which promotes mitochondrial biogenesis. Interestingly, CR not only suppressed age-related declines in cardiac function and mitochondrial biogenesis but blocked concomitant increases in cardiac HINT1 protein levels and maintained Tfam transcription. Furthermore, expression of the lncRNA Caren, which inhibits Hint1 mRNA translation, decreased with age in heart, and CR suppressed this effect. Finally, decreased HINT1 expression due to Caren overexpression antagonized age-related declines in mitochondrial biogenesis, ameliorating age-related cardiac dysfunction, exercise intolerance, and exercise-induced cardiac damage and subsequent death of mice.

CONCLUSION

Our findings suggest that mitochondrial biogenesis in cardiomyocytes decreases with age and could underlie cardiac dysfunction, and that the Caren-HINT1-mitochondrial biogenesis axis may constitute a mechanism linking CR to resistance to cardiac aging. We also show that ameliorating declines in mitochondrial biogenesis in cardiomyocytes could counteract age-related declines in cardiac function, and that this strategy may improve exercise tolerance and extend so-called "healthy life span".

Effect of Polyphenol Supplementation on Adiposity: A Systematic Review of Randomized Clinical Trials

PURPOSE OF REVIEW

The obesity is a multifactorial disease, result of high adiposity and excessive body fat, with closed relation to the development of other chronic disease. The growing obesity-related costs has relevant public health impact. In turn, the polyphenol is a dietary bioactive compound with recognized antioxidant propriety and healthy benefits. The polyphenol supplementation can be a promising strategy for obesity treatment, due to its potential antiadipogenic and metabolic control effects, improving quality of life of this population. This systematic review evaluated the effect of polyphenol supplementation on adiposity in overweight adults and elderly people (Systematic Review Registration: CRD42024586193).

RECENT FINDINGS

Current research demonstrates that polyphenol supplementation resulted in a significant decrease in markers of central adiposity (percentage of body fat, fat mass, waist circumference) and visceral adiposity (visceral adipose tissue). The mechanisms may be involved in the activation of lipid turnover pathways, AMPK activation and suppression of transcription factors (SREBPs, PPAR-γ and C/EBP-α) and key enzymes in lipid synthesis in adipose tissue. Furthermore, polyphenol supplementation has also beneficial effects on controlling of blood pressure, blood glucose and lipid profile, contribute to the prevention of other chronic metabolic disorders. Adiposity refers to the distribution of body fat, closely related to cardiometabolic risk, while polyphenols are phytochemicals with potential health-promoting effects. However, the role of these bioactive compounds in controlling adiposity is not well established. This systematic review presents antiadipogenic and metabolic control effects of the dietary polyphenol supplementation. However, there is no consensus on a specific dosage or form of presentation that generates the best results. Further studies are needed to elucidate better the potential effect of these compounds and related-pathway, to perform clinical validation of their use, and to establish the benefits of their long-term use.

The Many Facets of PPAR-γ Agonism in Obesity and Associated Comorbidities: Benefits, Risks, Challenges, and Future Directions

PURPOSE OF REVIEW

Obesity is strongly associated with cardiometabolic disorders and certain malignancies, emphasizing the key role of adipose tissue in human health. While incretin mimetics have shown effectiveness in glycemic control and weight loss, a holistic strategy for combating obesity and associated comorbidities remains elusive. This review explores peroxisome proliferator-activated receptor gamma (PPAR-γ) agonism as a potential therapeutic approach, highlighting its benefits, addressing its limitations, and outlining future directions for developing more effective treatment strategies.

RECENT FINDINGS

Both natural and synthetic PPAR-γ agonists hold significant therapeutic potential as insulin sensitizers, while also demonstrating anti-inflammatory properties and playing a critical role in regulating lipid metabolism. However, the clinical use of natural agonists is limited by poor bioavailability, while synthetic agents like thiazolidinediones are associated with adverse effects, including fluid retention, weight gain, and bone loss. Current research is focused on developing modified, tissue-specific PPAR-γ agonists, as well as dual PPAR-α/PPAR-γ agonists, with improved safety profiles to mitigate these side effects. Nanotechnology-based drug delivery systems also hold promise for enhancing bioavailability and therapeutic efficacy. Furthermore, the transformative potential of machine learning and artificial intelligence offers opportunities to accelerate advancements in this field. PPAR-γ agonists exhibit significant potential in addressing metabolic syndrome, cardiovascular disease, and cancer. However, their clinical use is restricted by safety concerns and suboptimal pharmacokinetics. Innovations in modified PPAR-γ agonists, nanotechnology-based delivery systems, and computational tools hold promise for creating safer and more effective therapeutic options for obesity and its associated disorders.

Lycium barbarum glycopeptide ameliorates aging phenotypes and enhances cardiac metabolism by activating the PINK1/Parkin-mediated mitophagy pathway in D-galactose-induced mice

BACKGROUND

Aging is a complex biological process that disrupts tissue structure and impairs physiological function, which contributes to the development of age-related diseases such as cardiovascular disorders. However, effective treatment strategies are lacking.

OBJECTIVE

To investigate the geroprotective effects of Lycium barbarum glycopeptide (LbGp) and its potential mechanisms in a D-galactose-induced accelerated aging mouse model.

METHODS

Mice were subcutaneously injected with D-galactose (500 mg/kg/day) for 12 weeks to induce aging, while LbGp was orally administered (100 mg/kg/day) throughout the study. The geroprotective effects of LbGp were assessed by behavioral tests, cardiac echocardiography, pathohistological and transcriptomic analyses. Transmission electron microscopy was used to observe the ultrastructure of mitochondria. Mitochondrial stress assays and JC-1 fluorescent probe were conducted to evaluate mitochondrial function. Flow cytometer and western blot were performed to assess mitophagy flux.

RESULTS

LbGp treatment improved the aging phenotypes of D-galactose-induced mice, with a pronounced enhancement in cardiac function compared to neurocognitive and skeletal muscle functions. Transcriptome analysis indicated that LbGp ameliorated energy metabolism in the heart. Mitochondrial assays revealed LbGp improved mitochondrial function and preserved structural integrity of the mitochondrial inner membrane. LbGp attenuated mitochondrial fission and restored impaired PINK1/Parkin-mediated mitophagy pathway caused by D-galactose in cardiomyocytes.

CONCLUSION

LbGp can ameliorate aging phenotypes and enhance cardiac metabolism by activating the PINK1/Parkin-mediated mitophagy pathway in D-galactose-induced mice. These findings underscore its potential as a therapeutic agent for aging and aging-related cardiovascular diseases.

Borneol Ameliorates Non-Alcoholic Fatty Liver Disease via Promoting AMPK-Mediated Lipophagy

Despite the worldwide surge in the prevalence of non-alcoholic fatty liver disease (NAFLD), however, no efficacious treatment has been clinically approved to date for combating this condition, necessitating elucidation of new therapeutic compounds. Our research presented evidence pertaining to the successful induction of NAFLD in C57BL/6 mice using a multiple liver insults paradigm. This was achieved by concurrently administering thioacetamide (100 mg/kg i.p.) along with high-fat and high-fructose diet (HFFrD) for 10 weeks. Following this, the beneficial effect of borneol, a bicyclic monoterpenoid, was observed in NAFLD mice in a dose-dependent manner. Borneol administration for 4 weeks led to significant improvement in morphometric, metabolic profiles, liver functions, and oxidative stress parameters. Accumulation of lipids in hepatic tissues, which is characteristic feature of NAFLD, was confirmed by H&E, as well as oil-red O staining was alleviated by borneol. Our investigation elucidated the pro-autophagic effect of borneol via AMPK activation, thereby leading to the downstream activation of autophagy effector proteins, that is, Beclin1, ATG5, ATG7, and LC3 I-II, which helps to diminish the hepatic lipid loads through augmentation of lipophagy. This study demonstrates that borneol combats NAFLD through augmentation of AMPK-mediated lipophagy offering a promising therapeutic strategy against NAFLD.

Caloric restriction and its mimetics in heart failure with preserved ejection fraction: mechanisms and therapeutic potential

The global increase in human life expectancy, coupled with an unprecedented rise in the prevalence of obesity, has led to a growing clinical and socioeconomic burden of heart failure with preserved ejection fraction (HFpEF). Mechanistically, the molecular and cellular hallmarks of aging are omnipresent in HFpEF and are further exacerbated by obesity and associated metabolic diseases. Conversely, weight loss strategies, particularly caloric restriction, have shown promise in improving health status in patients with HFpEF and are considered the gold standard for promoting longevity and healthspan (disease-free lifetime) in model organisms. In this review, we implicate fundamental mechanisms of aging in driving HFpEF and elucidate how caloric restriction mitigates the disease progression. Furthermore, we discuss the potential for pharmacologically mimicking the beneficial effects of caloric restriction in HFpEF using clinically approved and emerging caloric restriction mimetics. We surmise that these compounds could offer novel therapeutic avenues for HFpEF and alleviate the challenges associated with the implementation of caloric restriction and other lifestyle modifications to reduce the burden of HFpEF at a population level.

Calorie restriction modulates mitochondrial dynamics and autophagy in leukocytes of patients with obesity

BACKGROUND

Although it is established that caloric restriction offers metabolic and clinical benefits, the molecular mechanisms underlying these effects remain unclear. Thus, this study aimed to investigate whether caloric restriction can modulate mitochondrial function and remodeling and stimulate autophagic flux in the PBMCs of patients with obesity.

METHODS

This was an interventional study of 38 obese subjects (BMI >35 kg/m2) who underwent 6 months of dietary therapy, including a 6-week very-low-calorie diet (VLCD) followed by an 18-week low-calorie diet (LCD). We determined clinical variables, mitochondrial function parameters (by fluorescence imaging of mitochondrial ROS and membrane potential), and protein expression of markers of mitochondrial dynamics (MNF1, MFN2, OPA, DRP1 and FIS1) and autophagy (LC3, Beclin, BCL2 and NBR1) by Western blot.

RESULTS

Caloric restriction induced an improvement in metabolic outcomes that was accompanied by an increase in AMPK expression, a decrease of mitochondrial ROS and mitochondrial membrane potential, which was associated with increased markers of mitochondrial dynamics (MFN2, DRP1 and FIS1) and activation of autophagy as evidenced by augmented LC3 II/I, Beclin1 and NBR1, and a decrease in BCL2.

CONCLUSION

These findings shed light on the specific molecular mechanisms by which caloric restriction facilitates metabolic improvements, highlighting the relevance of pathways involving energy homeostasis and cell recovery, including mitochondrial function and dynamics and autophagy.

Mitophagy Unveiled: Exploring the Nexus of Mitochondrial Health and Neuroendocrinopathy

Mitochondria play a pivotal role in cellular metabolism, energy production, and apoptotic signaling, making mitophagy, the selective degradation of damaged mitochondria, crucial for mitochondrial health. Dysregulation of mitophagy has been implicated in various neuroendocrinopathies, yet the mechanisms linking these processes remain poorly understood. This review aims to explore the intersection between mitophagy and neuroendocrinopathy, addressing the critical gaps in knowledge regarding how mitochondrial dysfunction may contribute to the pathophysiology of neuroendocrine disorders. We conducted a comprehensive literature review of studies published on mitophagy and neuroendocrinopathies, focusing on data that elucidate the pathways involved and the clinical implications of mitochondrial health in neuroendocrine contexts. Our findings indicate that altered mitophagy may lead to the accumulation of dysfunctional mitochondria, contributing to neuroendocrine dysregulation. We present evidence linking impaired mitochondrial clearance to disease models of conditions such as metabolic syndrome, depression, and stress-related disorders, highlighting the potential for therapeutic interventions targeting mitophagy. While significant advances have been made in understanding mitochondrial biology, the direct interplay between mitophagy and neuroendocrinopathies remains underexplored. This review underscores the necessity for further research to elucidate these connections, which may offer novel insights into disease mechanisms and therapeutic strategies for treating maladaptive neuroendocrine responses.

Linagliptin mitigates cisplatin-induced kidney impairment via mitophagy regulation in rats, with emphasis on SIRT-3/PGC-1α, PINK-1 and Parkin-2

Cisplatin (CDDP) often leads to kidney impairment, limiting its effectiveness in cancer treatment. The lack of mitophagy in proximal tubules exacerbates this issue. Hence, targeting SIRT-3 and PGC1-α shows promise in mitigating CDDP-induced kidney damage. The potential renoprotective effects of linagliptin, however, remain poorly understood. This study represents the first exploration of linagliptin's impact on CDDP-induced kidney impairment in rats, emphasizing its potential role in mitophagic pathways. The experiment involved four rat groups: Group (I) received saline only, Group (II) received a single intraperitoneal injection of CDDP at 6 mg/kg. Groups (III) and (IV) received linagliptin at 6 and 10 mg/kg p.o., respectively, seven days before CDDP administration, continuing for an additional four days. Various parameters, including renal function tests, oxidative stress, TNF-α, IL-1β, IL-6, PGC-1α, FOXO-3a, p-ERK1, and the gene expression of SIRT-3 and P62 in renal tissue, were assessed. Linagliptin improved renal function, increased antioxidant enzyme activity, and decreased IL-1β, TNF-α, and IL-6 expression. Additionally, linagliptin significantly upregulated PGC-1α and PINK-1/Parkin-2 expression while downregulating P62 expression. Moreover, linagliptin activated FOXO-3a and SIRT-3, suggesting a potential enhancement of mitophagy. Linagliptin demonstrated a positive impact on various factors related to kidney health in the context of CDDP-induced impairment. These findings suggest a potential role for linagliptin in improving cancer treatment outcomes. Clinical trials are warranted to further investigate and validate its efficacy in a clinical setting.

TSG Extends the Longevity of Caenorhabditis elegans by Targeting the DAF-16/SKN-1/SIR-2.1-Mediated Mitochondrial Quality Control Process

The improvement of mitochondrial function is described as a strategy for alleviating oxidative stress and intervening in the aging process. 2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-glucoside (TSG) is one of the major bioactive components isolated from Polygonum multiflorum Thunb, and it exhibits multiple activities, including antioxidant and anti-inflammatory effects. In this study, we found that 200 μM TSG significantly extended the mean lifespan of Caenorhabditis elegans by 16.48% and improved health status by delaying age-associated physiological decline in worms. The longevity prolongation effect of TSG depended on the regulation of the mitochondrial quality control process mediated by DAF-16/FOXO, SKN-1/Nrf2 and SIR-2.1/SIRT1 to improve mitochondrial function. Moreover, TSG treatment obviously alleviated the proteotoxicity of β-amyloid and tau proteins in worms. Our findings indicated that TSG is a promising natural product for preventing aging and treating aging-associated neurodegenerative diseases by regulating the mitochondrial quality control process to improve mitochondrial function.

The role of polyphenols in modulating mitophagy: Implications for therapeutic interventions

This review rigorously assesses the burgeoning research into the role of polyphenols in modulating mitophagy, an essential cellular mechanism for the targeted removal of impaired mitochondria. These natural compounds, known for their low toxicity, are underscored for their potential in therapeutic strategies against a diverse array of diseases, such as neurodegenerative, cardiovascular, and musculoskeletal disorders. The analysis penetrates deeply into the molecular mechanisms whereby polyphenols promote mitophagy, particularly by influencing crucial signaling pathways and transcriptional regulators, including the phosphatase and tensin homolog (PTEN) induced putative kinase 1 (PINK1)/parkin and forkhead box O3 (FOXO3a) pathways. Noteworthy discoveries include the neuroprotective properties of resveratrol and curcumin, which affect both autophagic pathways and mitochondrial dynamics, and the pioneering integration of polyphenols with other natural substances to amplify therapeutic effectiveness. Furthermore, the review confronts the issue of polyphenol bioavailability and emphasizes the imperative for clinical trials to corroborate their therapeutic viability. By delivering an exhaustive synthesis of contemporary insights and recent advancements in polyphenol and mitophagy research, this review endeavors to catalyze additional research and foster the creation of innovative therapeutic modalities that exploit the distinctive attributes of polyphenols to manage and prevent disease.

Multi-omics revealed anti-fatigue property of polyphenol from areca nut

BACKGROUND

Areca nut polyphenols (AP) that extracted from areca nut, have been demonstrated for their potential of anti-fatigue effects. However, the underlying mechanisms for the anti-fatigue properties of AP has not been fully elucidated to date. Previous studies have predominantly concentrated on single aspects, such as antioxidation and anti-inflammation, yet have lacked comprehensive multi-dimensional analyses.

PURPOSE

To explore the underlying mechanism of AP in exerting anti-fatigue effects.

METHODS

In this study, we developed a chronic sleep deprivation-induced fatigue model and used physiological, hematological, and biochemical indicators to evaluate the anti- fatigue efficacy of AP. Additionally, a multi-omics approach was employed to reveal the anti-fatigue mechanisms of AP from the perspective of microbiome, metabolome, and proteome.

RESULTS

The detection of physiology, hematology and biochemistry index indicated that AP markedly alleviate mice fatigue state induced by sleep deprivation. The 16S rRNA sequencing showed the AP promoted the abundance of probiotics (Odoribacter, Dubosiella, Marvinbryantia, and Eubacterium) and suppressed harmful bacteria (Ruminococcus). On the other hand, AP was found to regulate the expression of colonic proteins, such as increases of adenosine triphosphate (ATP) synthesis and mitochondrial function related proteins, including ATP5A1, ATP5O, ATP5L, ATP5H, NDUFA, NDUFB, NDUFS, and NDUFV. Serum metabolomic analysis revealed AP upregulated the levels of anti-fatigue amino acids, such as taurine, leucine, arginine, glutamine, lysine, and l-proline. Hepatic proteins express levels, especially tricarboxylic acid (TCA) cycle (CS, SDHB, MDH2, and DLST) and redox-related proteins (SOD1, SOD2, GPX4, and PRDX3), were significantly recovered by AP administration. Spearman correlation analysis uncovered the strong correlation between microbiome, metabolome and proteome, suggesting the anti-fatigue effects of AP is attribute to the energy homeostasis and redox balance through gut-liver axis.

CONCLUSION

AP increased colonic ATP production and improve mitochondrial function by regulating gut microbiota, and further upregulated anti-fatigue amino acid levels in the blood. Based on the gut-liver axis, AP upregulated the hepatic tricarboxylic acid cycle and oxidoreductase-related protein expression, regulating energy homeostasis and redox balance, and ultimately exerting anti-fatigue effects. This study provides insights into the anti-fatigue mechanisms of AP, highlighting its potential as a therapeutic agent.

Ferulic acid restores mitochondrial dynamics and autophagy via AMPK signaling pathway in a palmitate-induced hepatocyte model of metabolic syndrome

Mitochondrial dysfunction, characterized by elevated oxidative stress, impaired energy balance, and dysregulated mitochondrial dynamics, is a hallmark of metabolic syndrome (MetS) and its comorbidities. Ferulic acid (FA), a principal phenolic compound found in whole grains, has demonstrated potential in ameliorating oxidative stress and preserving energy homeostasis. However, the influence of FA on mitochondrial health within the context of MetS remains unexplored. Moreover, the impact of FA on autophagy, which is essential for maintaining energy homeostasis and mitochondrial integrity, is not fully understood. Here, we aimed to study the mechanisms of action of FA in regulating mitochondrial health and autophagy using palmitate-treated HepG2 hepatocytes as a MetS cell model. We found that FA improved mitochondrial health by restoring redox balance and optimizing mitochondrial dynamics, including biogenesis and the fusion/fission ratio. Additionally, FA was shown to recover autophagy and activate AMPK-related cell signaling. Our results provide new insights into the therapeutic potential of FA as a mitochondria-targeting agent for the prevention and treatment of MetS.

Tannic acid alleviates 3-nitropropionic acid-induced ovarian damage in Brandt's vole (Lasiopodomys brandtii)

Tannic acid (TA) is a polyphenol with antioxidant properties present in various plants. In this study, we explored the protective effect of TA against ovarian oxidative stress in Brandt's voles and its underlying mechanism. At various doses, 3-nitropropionic acid (3-NPA) was intraperitoneally injected into Brandt's voles to simulate ovarian oxidative stress. Thereafter, various doses of TA were intragastrically administered to examine the protective effect of TA against 3-NPA-induced ovarian damage. Changes in inflammation, autophagy, apoptosis, and oxidative stress-related factors were investigated through various biochemical and histological techniques. Ovarian oxidative stress was successfully induced by the intraperitoneal administration of 12.5 mg/kg 3-NPA for 18 days. As a result, the ovarian coefficient decreased and ovarian tissue fibrosis was induced. TA treatment effectively alleviated the increase in luteinizing hormone and follicle-stimulating hormone levels; the decrease in estradiol, progesterone, and anti-Müllerian hormone levels; and the decline in fertility induced by 3-NPA. Compared to that in the 3-NPA group, TA decreased the expression of autophagy-related proteins beclin-1 and LC3, as well as the level of apoptosis. It also activated the AKT/mTOR signaling pathway, downregulated PTEN and p-NF-κB expression, and upregulated Nrf2 expression. In conclusion, our findings indicate that TA could inhibit autophagy via the regulation of AKT/mTOR signaling, suppressing oxidative damage and inflammatory responses through Nrf2 to alleviate 3-NPA-induced ovarian damage. Collectively, the current findings highlight the protective effects of TA in Brandt's vole, where it promotes the maintenance of normal ovarian function.

Methylated urolithin A, mitigates cognitive impairment by inhibiting NLRP3 inflammasome and ameliorating mitochondrial dysfunction in aging mice

Effective therapeutic interventions for elderly patients are lacking, despite advances in pharmacotherapy. Methylated urolithin A (mUro A), a modified ellagitannin (ET)-derived metabolite, exhibits anti-inflammatory, antioxidative, and anti-apoptotic effects. Current research has primarily investigated the neuroprotective effects of mUroA in aging mice and explored the underlying mechanisms. Our study used an in vivo aging model induced by d-galactose (D-gal) to show that mUro A notably improved learning and memory, prevented synaptic impairments by enhancing synaptic protein expression and increasing EPSCs, and reduced oxidative damage in aging mice. mUro A alleviated the activation of the NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) inflammasome, leading to reduced glial cell activity and neuroinflammation in both accelerated aging and naturally senescent mouse models. Moreover, mUroA enhanced the activity of TCA cycle enzymes (PDH, CS, and OGDH), decreased 8-OHdG levels, and raised ATP and NAD+ levels within the mitochondria. At the molecular level, mUro A decreased phosphorylated p53 levels and increased the expression of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), thus enhancing mitochondrial function. In conclusion, mUro A alleviates cognitive impairment in aging mice by suppressing neuroinflammation through NLRP3 inflammasome inhibition and restoring mitochondrial function via the p53-PGC-1α pathway. This suggests its potential therapeutic agent for brain aging and aging-related diseases.

Mitochondrial sirtuin 3 and role of natural compounds: the effect of post-translational modifications on cellular metabolism

Sirtuins (SIRTs) are a family of proteins with enzymatic activity. In particular, they are a family of class III NAD+-dependent histone deacetylases and ADP-ribosyltransferases. NAD+-dependent deac(et)ylase activities catalyzed by sirtuin include ac(et)ylation, propionylation, butyrylation, crotonylation, manylation, and succinylation. Specifically, human SIRT3 is a 399 amino acid protein with two functional domains: a large Rossmann folding motif and NAD+ binding, and a small complex helix and zinc-binding motif. SIRT3 is widely expressed in mitochondria-rich tissues and is involved in maintaining mitochondrial integrity, homeostasis, and function. Moreover, SIRT3 regulates related diseases, such as aging, hepatic, kidney, neurodegenerative and cardiovascular disease, metabolic diseases, and cancer development. In particular, one of the most significant and damaging post-translational modifications is irreversible protein oxidation, i.e. carbonylation. This process is induced explicitly by increased ROS production due to mitochondrial dysfunction. SIRT3 is carbonylated by 4-hydroxynonenal at the level of Cys280. The carbonylation induces conformational changes in the active site, resulting in allosteric inhibition of SIRT3 activity and loss of the ability to deacetylate and regulate antioxidant enzyme activity. Phytochemicals and, in particular, polyphenols, thanks to their strong antioxidant activity, are natural compounds with a positive regulatory action on SIRT3 in various pathologies. Indeed, the enzymatic SIRT3 activity is modulated, for example, by different natural polyphenol classes, including resveratrol and the bergamot polyphenolic fraction. Thus, this review aims to elucidate the mechanisms by which phytochemicals can interact with SIRT3, resulting in post-translational modifications that regulate cellular metabolism.

Healthy Aging in Times of Extreme Temperatures: Biomedical Approaches

Climate extremes and rising energy prices present interconnected global health risks. Technical solutions can be supplemented with biomedical approaches to promote healthy longevity in hot and cold conditions. In summer, reducing basal metabolic rate through mild caloric restriction or CR mimetics, such as resveratrol, can potentially be used to lower body temperature. In winter, activating brown adipose tissue (BAT) for non-shivering thermogenesis and improved metabolic health can help adaptation to colder environments. Catechins found in green tea and in other food could be alternatives to drugs for these purposes. This review examines and discusses the biomedical evidence supporting the use of CR mimetics and BAT activators for health benefits amid increasingly extreme temperatures.

Nutritive value, biological properties, health benefits and applications of Tetrapleura tetraptera: An updated comprehensive review

Due to the health benefits that medicinal plants present, they are applied in traditional healthcare in developing and developed countries alike. Tetrapleura tetraptera, a flowering plant mostly found in the western part of Africa has an essential chemical composition that gives it nutritive value and medicinal capacities. This review aims to highlight the nutritional attributes, biological properties, health benefits, and applications of T. tetraptera. The fruit of the plant has been revealed to possess about 58.48-63. 86% carbohydrates, 251.22-288.62 mg/g potassium, 182.11-200.02 mg/g calcium, 322.00-342.00 mg/g manganese, and 0.02-4.69 mg/g vitamins. Also, active phytochemical compounds including phenols (3.51 ± 0.03 mgGAE/g), flavonoids (0.87 ± 0.03 mgQE/g), saponins (4.27 ± 0.03 mgDE/g), tannins (23.87 ± 0.44 mg/100 g), and alkaloids (5.03 ± 0.15% w/w) have been discovered in the fruit of T. tetraptera. The plant's abundant phytochemicals account for its antioxidant, antimicrobial, anti-inflammatory, anti-diabetic, anti-parasitic, and anti-proliferative activities. These biological properties in turn translate to health benefits including lower blood pressure, enhanced immune system, malaria treatment, diabetes and hypertension management, and cancer prevention. The health-promoting assets of T. tetraptera underscore its applications in beverage production, food preservation and flavoring, feed supplementation, and pharmaceutical formulations. The data gathered in this piece is crucial for industrial food processing and the creation of potent pharmaceutical products and functional foods with superior health attributes.

Mitochondrial Dysfunction as the Major Basis of Brain Aging

The changes in the properties of three biological events that occur with cerebral aging are discussed. These adverse changes already begin to develop early in mid-life and gradually become more pronounced with senescence. Essentially, they are reflections of the progressive decline in effectiveness of key processes, resulting in the deviation of essential biochemical trajectories to ineffective and ultimately harmful variants of these programs. The emphasis of this review is the major role played by the mitochondria in the transition of these three important processes toward more deleterious variants as brain aging proceeds. The immune system: the shift away from an efficient immune response to a more unfocused, continuing inflammatory condition. Such a state is both ineffective and harmful. Reactive oxygen species are important intracellular signaling systems. Additionally, microglial phagocytic activity utilizing short lived reactive oxygen species contribute to the removal of aberrant or dead cells and bacteria. These processes are transformed into an excessive, untargeted, and persistent generation of pro-oxidant free radicals (oxidative stress). The normal efficient neural transmission is modified to a state of undirected, chronic low-level excitatory activity. Each of these changes is characterized by the occurrence of continuous activity that is inefficient and diffused. The signal/noise ratio of several critical biological events is thus reduced as beneficial responses are gradually replaced by their impaired and deleterious variants.

Mitochondrial-Targeted Metal-Phenolic Nanoparticles to Attenuate Intervertebral Disc Degeneration: Alleviating Oxidative Stress and Mitochondrial Dysfunction

As intervertebral disc degeneration (IVDD) proceeds, the dysfunctional mitochondria disrupt the viability of nucleus pulposus cells, initiating the degradation of the extracellular matrix. To date, there is a lack of effective therapies targeting the mitochondria of nucleus pulposus cells. Here, we synthesized polygallic acid-manganese (PGA-Mn) nanoparticles via self-assembly polymerization of gallic acid in an aqueous medium and introduced a mitochondrial targeting peptide (TP04) onto the nanoparticles using a Schiff base linkage, resulting in PGA-Mn-TP04 nanoparticles. With a size smaller than 50 nm, PGA-Mn-TP04 possesses pH-buffering capacity, avoiding lysosomal confinement and selectively accumulating within mitochondria through electrostatic interactions. The rapid electron exchange between manganese ions and gallic acid enhances the redox capability of PGA-Mn-TP04, effectively reducing mitochondrial damage caused by mitochondrial reactive oxygen species. Moreover, PGA-Mn-TP04 restores mitochondrial function by facilitating the fusion of mitochondria and minimizing their fission, thereby sustaining the vitality of nucleus pulposus cells. In the rat IVDD model, PGA-Mn-TP04 maintained intervertebral disc height and nucleus pulposus tissue hydration. It offers a nonoperative treatment approach for IVDD and other skeletal muscle diseases resulting from mitochondrial dysfunction, presenting an alternative to traditional surgical interventions.

Polyphenols: immunonutrients tipping the balance of immunometabolism in chronic diseases

Mounting evidence progressively appreciates the vital interplay between immunity and metabolism in a wide array of immunometabolic chronic disorders, both autoimmune and non-autoimmune mediated. The immune system regulates the functioning of cellular metabolism within organs like the brain, pancreas and/or adipose tissue by sensing and adapting to fluctuations in the microenvironment's nutrients, thereby reshaping metabolic pathways that greatly impact a pro- or anti-inflammatory immunophenotype. While it is agreed that the immune system relies on an adequate nutritional status to function properly, we are only just starting to understand how the supply of single or combined nutrients, all of them termed immunonutrients, can steer immune cells towards a less inflamed, tolerogenic immunophenotype. Polyphenols, a class of secondary metabolites abundant in Mediterranean foods, are pharmacologically active natural products with outstanding immunomodulatory actions. Upon binding to a range of receptors highly expressed in immune cells (e.g. AhR, RAR, RLR), they act in immunometabolic pathways through a mitochondria-centered multi-modal approach. First, polyphenols activate nutrient sensing via stress-response pathways, essential for immune responses. Second, they regulate mammalian target of rapamycin (mTOR)/AMP-activated protein kinase (AMPK) balance in immune cells and are well-tolerated caloric restriction mimetics. Third, polyphenols interfere with the assembly of NLR family pyrin domain containing 3 (NLRP3) in endoplasmic reticulum-mitochondria contact sites, inhibiting its activation while improving mitochondrial biogenesis and autophagosome-lysosome fusion. Finally, polyphenols impact chromatin remodeling and coordinates both epigenetic and metabolic reprogramming. This work moves beyond the well-documented antioxidant properties of polyphenols, offering new insights into the multifaceted nature of these compounds. It proposes a mechanistical appraisal on the regulatory pathways through which polyphenols modulate the immune response, thereby alleviating chronic low-grade inflammation. Furthermore, it draws parallels between pharmacological interventions and polyphenol-based immunonutrition in their modes of immunomodulation across a wide spectrum of socioeconomically impactful immunometabolic diseases such as Multiple Sclerosis, Diabetes (type 1 and 2) or even Alzheimer's disease. Lastly, it discusses the existing challenges that thwart the translation of polyphenols-based immunonutritional interventions into long-term clinical studies. Overcoming these limitations will undoubtedly pave the way for improving precision nutrition protocols and provide personalized guidance on tailored polyphenol-based immunonutrition plans.

Silibinin, a potential fasting mimetic, inhibits hepatocellular carcinoma by triggering extrinsic apoptosis

Fasting, without inducing malnutrition, has been shown to have various beneficial effects, including the inhibition of tumor initiation and progression. However, prolonged fasting poses challenges for many cancer patients, particularly those in intermediate and terminal stages. Thus, there is an urgent need for the development of fasting mimetics which harness the protective effects of fasting but more suitable for patients. In this study, we first highlighted the pivotal role of silibinin in AMP-activated protein kinase (AMPK) pathway and may serve, as a potential fasting mimetic via screening hepatoprotective drugs. Further metabolic analysis showed that silibinin inhibited the adenosine triphosphate (ATP) levels, glucose uptake and diminished glycolysis process, which further confirmed that silibinin served as a fasting mimetic. In addition, fasting synergized with silibinin, or used independently, to suppress the growth of hepatocellular carcinoma (HCC) in vivo. Mechanistically, silibinin upregulated death receptor 5 (DR5) through AMPK activation, and thus promoting extrinsic apoptosis and inhibiting HCC growth both in vitro and in vivo. Inhibition of AMPK using small interfering RNA (siRNA) or compound C, an AMPK inhibitor, significantly attenuated the upregulation of DR5 and the apoptotic response induced by silibinin. These findings suggest that silibinin holds promise as a fasting mimetic and may serve as an adjuvant drug for HCC treatment.

Autophagy-related 7 proteindependent autophagy mediates resveratrol-caused upregulation of mitochondrial biogenesis and steroidogenesis in aged Leydig cell

BACKGROUND

Mitochondrial dysfunction may contribute to decreased testosterone synthesis in aged Leydig cells. Resveratrol (RSV) as an antioxidant has been shown to exhibit multiple positive effects on mitochondrion, where steroidogenesis takes place. Whether RSV can improve steroidogenesis in aged testis is still unknown. This study investigates the effect of RSV on testosterone production during aging and corresponding changes in mitochondrial biogenesis and autophagy activity, which are closely associated with steroidogenesis. Whether ATG7, an important autophagy-related protein, functions in RSV-treated aged Leydig cells will also be explored.

METHODS AND RESULTS

Two-month-old male C57BL/6 mice were fed for 16 months by customized regular diet with or without RSV as diet supplement. Leydig cell line TM3 cells were treated with D-galactose to induce senescence, followed with or without RSV treatment. Results found that RSV supplement increased testosterone production in both aged mice and D-galactose-induced senescent Leydig cells. Western blot results revealed that RSV treatment elevated levels of steroidogenic rate-limiting enzymes StAR and 3β-HSD, as well as autophagy-related proteins LC3II, Beclin1, ATG5 and ATG7 and mitochondrial function-related proteins mtTFA and COXIV. However, after Atg7 was knocked down in senescent Leydig cells, even though RSV was added, levels of these proteins declined significantly, accompanied by decreased levels of mitochondrial transcript factors PGC-1α, mtTFA and NRF-1 and more fragmented mitochondria, demonstrating that Atg7 knockdown wrecked the protective effects of RSV on steroidogenesis in senescent Leydig cells.

CONCLUSION

ATG7-dependent autophagy plays a key role in RSV-brought testosterone production increase through regulating mitochondrial biogenesis in senescent Leydig cells.

Targeting mitophagy for neurological disorders treatment: advances in drugs and non-drug approaches

Mitochondria serve as a vital energy source for nerve cells. The mitochondrial network also acts as a defense mechanism against external stressors that can threaten the stability of the nervous system. However, excessive accumulation of damaged mitochondria can lead to neuronal death. Mitophagy is an essential pathway in the mitochondrial quality control system and can protect neurons by selectively removing damaged mitochondria. In most neurological disorders, dysfunctional mitochondria are a common feature, and drugs that target mitophagy can improve symptoms. Here, we reviewed the role of mitophagy in Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, stroke, and traumatic brain injuries. We also summarized drug and non-drug approaches to promote mitophagy and described their therapeutic role in neurological disorders in order to provide valuable insight into the potential therapeutic agents available for neurological disease treatment. However, most studies on mitophagy regulation are based on preclinical research using cell and animal models, which may not accurately reflect the effects in humans. This poses a challenge to the clinical application of drugs targeting mitophagy. Additionally, these drugs may carry the risk of intolerable side effects and toxicity. Future research should focus on the development of safer and more targeted drugs for mitophagy.

Adaptive Nanoparticle-Mediated Modulation of Mitochondrial Homeostasis and Inflammation to Enhance Infected Bone Defect Healing

Infected bone defects (IBDs) exhibit impaired healing due to excessive inflammation triggered by pathogen-associated molecular patterns (PAMPs) from bacteria. As a vital factor in orchestrating immune responses, mitochondrial homeostasis maintenance is central to inflammation blockade. This research developed a chameleon-like nanoplatform by covering hydroxyapatite nanoparticles with a cerium ion coordinated tannic acid supramolecular network (HA@Ce-TA), which adaptively functions to regulate mitochondrial homeostasis based on intra- and extracellular environments. Extracellularly, acidic conditions activate HA@Ce-TA's peroxidase/oxidase-mimicking activity to produce reactive oxygen species (ROS), and external near-infrared (NIR) irradiation excites nanoscale Ce-TA to produce hyperthermia, which is found and explained by chemical computation. ROS production with photothermal therapy can eliminate bacteria effectively and reduce mitochondrial stress. Intracellularly, HA@Ce-TA remodels mitochondrial dynamics by upregulating mitochondrial fusion genes and eliminates excessive ROS by mimicking superoxidase/catalase. Consequently, this comprehensive modulation of mitochondrial homeostasis inhibits inflammasome overactivation. In vitro and in vivo studies showed HA@Ce-TA can modulate the mitochondria-centered inflammatory cascade to enhance IBD treatment, highlighting the potential of engineering nanotherapeutics to recalibrate mitochondrial homeostasis as an infected disease-modifying intervention.

Chlorogenic Acid Alleviated AFB1-Induced Hepatotoxicity by Regulating Mitochondrial Function, Activating Nrf2/HO-1, and Inhibiting Noncanonical NF-κB Signaling Pathway

Aflatoxin B1 (AFB1), a kind of mycotoxin, imposes acute or chronic toxicity on humans and causes great public health concerns. Chlorogenic acid (CGA), a natural phenolic substance, shows a powerful antioxidant and anti-inflammatory effect. This study was conducted to investigate the effect and mechanism of CGA on alleviating cytotoxicity induced by AFB1 in L-02 cells. The results showed that CGA (160 μM) significantly recovered cell viability and cell membrane integrity in AFB1-treated (8 μM) cells. Furthermore, it was found that CGA reduced AFB1-induced oxidative injury by neutralizing reactive oxygen species (ROS) and activating the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway. In addition, CGA showed anti-inflammatory effects as it suppressed the expression of inflammation-related genes (IL-6, IL-8, and TNF-α) and AFB1-induced noncanonical nuclear factor kappa-B (NF-κB) activation. Moreover, CGA mitigated AFB1-induced apoptosis by maintaining the mitochondrial membrane potential (MMP) and inhibiting mRNA expressions of Caspase-3, Caspase-8, Bax, and Bax/Bcl-2. These findings revealed a possible mechanism: CGA prevents AFB1-induced cytotoxicity by maintaining mitochondrial membrane potential, activating Nrf2/HO-1, and inhibiting the noncanonical NF-κB signaling pathway, which may provide a new direction for the application of CGA.

Phytoconstituent Profiles Associated with Relevant Antioxidant Potential and Variable Nutritive Effects of the Olive, Sweet Almond, and Black Mulberry Gemmotherapy Extracts

The extracts of whole plants or specific organs from different plant species are gaining increasing attention for their phytotherapy applications. Accordingly, we prepared standardized gemmotherapy extracts (GTEs) from young shoots/buds of olive (Olea europaea), sweet almond (Prunus amygdalus), and black mulberry (Morus nigra), and analyzed the corresponding phytonutrient profiles. We identified 42, 103, and 109 phytonutrients in the olive, almond, and black mulberry GTEs, respectively, containing amino acids, vitamins, polyphenols, flavonoids, coumarins, alkaloids, iridoids, carboxylic acids, lignans, terpenoids, and others. In order to assess the physiological effects generated by the GTEs, we developed a translational nutrition model based on Drosophila melanogaster and Cyprinus carpio. The results indicate that GTEs could influence, to a variable extent, viability and ATP synthesis, even though both are dependent on the specific carbohydrate load of the applied diet and the amino acid and polyphenol pools provided by the GTEs. It seems, therefore, likely that the complex chemical composition of the GTEs offers nutritional properties that cannot be separated from the health-promoting mechanisms that ultimately increase viability and survival. Such an approach sets the paves the way for the nutritional genomic descriptions regarding GTE-associated health-promoting effects.

The Emerging Role of Flavonoids in Autism Spectrum Disorder: A Systematic Review

Although autism spectrum disorder (ASD) is a multifaceted neurodevelopmental syndrome, accumulating evidence indicates that oxidative stress and inflammation are common features of ASD. Flavonoids, one of the largest and best-investigated classes of plant-derived compounds, are known to exert antioxidant, anti-inflammatory, and neuroprotective effects. This review used a systematic search process to assess the available evidence on the effect of flavonoids on ASD. A comprehensive literature search was carried out in PubMed, Scopus, and Web of Science databases following the PRISMA guidelines. A total of 17 preclinical studies and 4 clinical investigations met our inclusion criteria and were included in the final review. Most findings from animal studies suggest that treatment with flavonoids improves oxidative stress parameters, reduces inflammatory mediators, and promotes pro-neurogenic effects. These studies also showed that flavonoids ameliorate the core symptoms of ASD, such as social deficits, repetitive behavior, learning and memory impairments, and motor coordination. However, there are no randomized placebo-controlled trials that support the clinical efficacy of flavonoids in ASD. We only found open-label studies and case reports/series, using only two flavonoids such as luteolin and quercetin. These preliminary clinical studies indicate that flavonoid administration may improve specific behavioral symptoms of ASD. Overall, this review is the first one to systematically report evidence for the putative beneficial effects of flavonoids on features of ASD. These promising preliminary results may provide the rationale for future randomized controlled trials aimed at confirming these outcomes.

Dietary Polyphenols and Obesity: A Review of Polyphenol Effects on Lipid and Glucose Metabolism, Mitochondrial Homeostasis, and Starch Digestibility and Absorption

Obesity is a major global public health concern, limiting socio-economic development and human productivity. As studies focus on finding sustainable solutions to this challenge, polyphenols have shown promising results and have become a research focus. This is mainly because of associated lower risks of side effects with their use, compared to synthetic pharmaceuticals. In this study, the anti-obesity potentials of dietary polyphenols have been reviewed. Using a narrative approach, the biological activities of polyphenols and their influence on energy metabolism and mechanisms are discussed. Specifically, their roles in insulin-dependent glucose uptake, insulin sensitivity, lipid metabolism and storage in adipocytes, starch digestibility, and regulation of mitophagy and mitogenesis in muscle cells and adipocytes, were considered. After considering the major findings of many related studies, it was confirmed that polyphenols can prevent and ameliorate obesity by fighting insulin resistance (IR) induced by pro-inflammatory cytokines, scavenging reactive oxygen species (ROS) and limiting their effects, and by regulating the expression and/or activity of key enzymes along relevant pathways. More human studies are needed to reveal more about the anti-obesity effects of dietary polyphenols and their effective doses in humans.

Mitophagy: A promising therapeutic target for neuroprotection during ageing and age-related diseases

Mitochondria and mitochondria-mediated signalling pathways are known to control synaptic signalling, as well as long-lasting changes in neuronal structure and function. Mitochondrial impairment is linked to synaptic dysfunction in normal ageing and age-associated neurodegenerative ailments, including Parkinson's disease (PD) and Alzheimer's disease (AD). Both proteolysis and mitophagy perform a major role in neuroprotection, by maintaining a healthy mitochondrial population during ageing. Mitophagy, a highly evolutionarily conserved cellular process, helps in the clearance of damaged mitochondria and thereby maintains the mitochondrial and metabolic balance, energy supply, neuronal survival and neuronal health. Besides the maintenance of brain homeostasis, hippocampal mitophagy also helps in synapse formation, axonal development, dopamine release and long-term depression. In contrast, defective mitophagy contributes to ageing and age-related neurodegeneration by promoting the accumulation of damaged mitochondria leading to cellular dysfunction. Exercise, stress management, maintaining healthy mitochondrial dynamics and administering natural or synthetic pharmacological compounds are some of the strategies used for neuroprotection during ageing and age-related neurological diseases. The current review discusses the impact of defective mitophagy in ageing and age-associated neurodegenerative conditions, the underlying molecular pathways and potential therapies based on recently elucidated mitophagy-inducing strategies.

Targeting AMPK signaling by polyphenols: a novel strategy for tackling aging

Aging is an inevitable biological process and is accompanied by a gradual decline of physiological functions, such as the incidence of age-related diseases. Aging becomes a major burden and challenge for society to prevent or delay the occurrence and development of these age-related diseases. AMPK is a key regulator of intracellular energy and participates in the adaptation of calorie restriction. It is also an important mediator of nutritionally sensitive pathways that regulate the biological effects of nutrient active ingredients. AMPK can limit proliferation and activate autophagy. Recent studies have shown that nutritional intervention can delay aging and lessen age-related diseases in many animal and even human models. Polyphenols function as a natural antidote and are important anti-inflammatory and antioxidant agents in human diets. Polyphenols can prevent age-related diseases because they regulate complex networks of cellular processes such as oxidative damage, inflammation, cellular aging, and autophagy, and have also attracted wide attention as a potential beneficial substance for longevity. In this review, we systemically summarized the progress of targeting AMPK signaling by dietary polyphenols in aging prevention. Polyphenols can reduce oxidative stress and inflammatory response, and maintain the steady state of energy. Polyphenols can also modulate sirtuins/NAD+, nutrient-sensing, proteostasis, mitochondrial function, autophagy and senescence via targeting AMPK signaling. Therefore, targeting the AMPK signaling pathway by dietary polyphenols may be a novel anti-aging strategy.

Effects of bamboo leaf extract on energy metabolism, antioxidant capacity, and biogenesis of small intestine mitochondria in broilers

The present study was carried out to investigate the effects of bamboo leaf extract (BLE) on energy metabolism, antioxidant capacity, and biogenesis of broilers' small intestine mitochondria. A total of 384 one-day-old male Arbor Acres broiler chicks were randomly divided into four groups with six replicates each for 42 d. The control group was fed a basal diet, whereas the BLE1, BLE2, and BLE3 groups consumed basal diets with 1.0, 2.0, and 4.0 g/kg of BLE, respectively. Some markers of mitochondrial energy metabolism including isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, and malate dehydrogenase and some markers of redox system including total superoxide dismutase, malondialdehyde, and glutathione were measured by commercial colorimetric kits. Mitochondrial and cellular antioxidant genes, mitochondrial biogenesis-related genes, and mitochondrial DNA copy number were measured by quantitative real-time-polymerase chain reaction (qRT-PCR). Data were analyzed using the SPSS 19.0, and differences were considered as significant at P < 0.05. BLE supplementation linearly increased jejunal mitochondrial isocitrate dehydrogenase (P < 0.05) and total superoxide dismutase (P < 0.05) activity. The ileal manganese superoxide dismutase mRNA expression was linearly affected by increased dietary BLE supplementation (P < 0.05). Increasing BLE supplementation linearly increased jejunal sirtuin 1 (P < 0.05) and nuclear respiratory factor 1 (P < 0.05) mRNA expression. Linear (P < 0.05) and quadratic (P < 0.05) responses of the ileal nuclear respiratory factor 2 mRNA expression occurred with increased dietary BLE levels. In conclusion, BLE supplementation was beneficial to the energy metabolism, antioxidant capacity, and biogenesis of small intestine mitochondria in broilers. The dose of 4.0 g/kg BLE demonstrated the best effects.

Dietary Flavonoids and Adult Neurogenesis: Potential Implications for Brain Aging

Adult neurogenesis deficiency has been proposed to be a common hallmark in different age-related neurodegenerative diseases. The administration of flavonoids is currently reported as a potentially beneficial strategy for preventing brain aging alterations, including adult neurogenesis decline. Flavonoids are a class of plant-derived dietary polyphenols that have drawn attention for their neuroprotective and pro-cognitive effects. Although they undergo extensive metabolism and localize in the brain at low concentrations, flavonoids are now believed to improve cerebral vasculature and interact with signal transduction cascades involved in the regulation of adult neurogenesis. Furthermore, many dietary flavonoids have been shown to reduce oxidative stress and neuroinflammation, improving the neuronal microenvironment where adult neurogenesis occurs. The overall goal of this review is to summarize the evidence supporting the role of flavonoids in modulating adult neurogenesis as well as to highlight how these dietary agents may be promising candidates in restoring healthy brain function during physiological and pathological aging.

Optimized pressurized hot water extraction, HPLC/LC-MS characterization, and bioactivity of Tetrapleura tetraptera L. dry fruit polyphenols

Despite the global preference for green extraction methods in the recovery of plant bioactives, Tetrapleura tetraptera fruit polyphenols (TTP) are yet to receive considerable attention. For the first time, pressurized hot water extraction (PHWE) of TTP was optimized for total phenol content (TPC) and antioxidant activity (AA) using the Box Behnken design of response surface methodology. Predictor variables were time, temperature, and liquid-to-solid ratio. An optimum solution with a desirability of 0.805 was selected and parameters were 43 min, 220°C, and 60 ml g^-1 liquid-to-solid ratio, yielding TPC of 8.92 mg gallic acid equivalent per gram of sample on dry weight basis (GAE g^-1  dw^-1 ) and AA of 70.35%. Purified, optimized TTP were characterized and quantified using HPLC/LC-MS. PHWE mainly extracted rutin (379.04 µg g^-1 ), cyanidin-3-O-glucoside (chloride) (299.55 µg g^-1 ), naringenin 7-O-glucoside (240.11 µg g^-1 ), p-coumaric acid (177.28 µg g^-1 ), isorientin (150.43 µg g^-1 ), and gallic acid (118.06 µg g^-1 ) whereas cyanidin-3-O-glucoside (chloride) (83.27 µg g^-1 ), protocatechuic acid (61.37 µg g^-1 ), rutin (28.03 µg g^-1 ), and gallic acid (22.62 µg g^-1 ) were mainly extracted by hot water extraction, which was a control. PHWE-obtained TTP showed higher cellular antioxidant activity, cytotoxicity in human liver cancer cell lines (HepG2), and antimicrobial property against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis than control. The potential mechanisms underlying the biological activities of some of the major polyphenols extracted were briefly discussed. Considering the wide use of the T. tetraptera (TT) fruit in Africa in foods and medicine, the use of more efficient green extraction methods such as PHWE is recommended. PRACTICAL APPLICATION: This study serves as a baseline for optimizing pressurized hot water extraction, purification, identification, and quantification of Tetrapleura tetraptera polyphenols (TTP) and their biological activities, being the first of its kind. The varied biological effects shown can be exploited further for applications of TTP as nutraceutical agents and preservatives in foods in different forms. Also, the high amounts of gallic acid and other phenolic acids and flavonoids confirmed in this study make TTP good candidates for the development of metal-phenol network nanoparticles to enhance adequate solubility and distribution in food systems in light of the above proposed applications.

Polyphenols as potential metabolism mechanisms regulators in liver protection and liver cancer prevention

BACKGROUND

Liver cancer is one of the common malignancies. The dysregulation of metabolism is a driver of accelerated tumourigenesis. Metabolic changes are well documented to maintain tumour growth, proliferation and survival. Recently, a variety of polyphenols have been shown to have a crucial role both in liver disease prevention and metabolism regulation.

METHODS

We conducted a literature search and combined recent data with systematic analysis to comprehensively describe the molecular mechanisms that link polyphenols to metabolic regulation and their contribution in liver protection and liver cancer prevention.

RESULTS

Targeting metabolic dysregulation in organisms prevents and resists the development of liver cancer, which has important implications for identifying new therapeutic strategies for the management and treatment of cancer. Polyphenols are a class of complex compounds composed of multiple phenolic hydroxyl groups and are the main active ingredients of many natural plants. They mediate a broad spectrum of biological and pharmacological functions containing complex lipid metabolism, glucose metabolism, iron metabolism, intestinal flora imbalance, as well as the direct interaction of their metabolites with key cell-signalling proteins. A large number of studies have found that polyphenols affect the metabolism of organisms by interfering with a variety of intracellular signals, thereby protecting the liver and reducing the risk of liver cancer.

CONCLUSION

This review systematically illustrates that various polyphenols, including resveratrol, chlorogenic acid, caffeic acid, dihydromyricetin, quercetin, catechins, curcumin, etc., improve metabolic disorders through direct or indirect pathways to protect the liver and fight liver cancer.

Mitochondrial quality control mechanisms as therapeutic targets in doxorubicin-induced cardiotoxicity

Doxorubicin (DOX) is a chemotherapeutic drug that is utilized for solid tumors and hematologic malignancies, but its clinical application is hampered by life-threatening cardiotoxicity including cardiac dilation and heart failure. Mitochondrial quality control processes, including mitochondrial proteostasis, mitophagy, and mitochondrial dynamics and biogenesis, serve to maintain mitochondrial homeostasis in the cardiovascular system. Importantly, recent advances have unveiled a major role for defective mitochondrial quality control in the etiology of DOX cardiomyopathy. Moreover, specific interventions targeting these quality control mechanisms to preserve mitochondrial function have emerged as potential therapeutic strategies to attenuate DOX cardiotoxicity. However, clinical translation is challenging because of obscure mechanisms of action and potential adverse effects. The purpose of this review is to provide new insights regarding the role of mitochondrial quality control in the pathogenesis of DOX cardiotoxicity, and to explore promising therapeutic approaches targeting these mechanisms to aid clinical management.

Mitochondrial Aging and Senolytic Natural Products with Protective Potential

Living organisms do not disregard the laws of thermodynamics and must therefore consume energy for their survival. In this way, cellular energy exchanges, which aim above all at the production of ATP, a fundamental molecule used by the cell for its metabolisms, favor the formation of waste products that, if not properly disposed of, can contribute to cellular aging and damage. Numerous genes have been linked to aging, with some favoring it (gerontogenes) and others blocking it (longevity pathways). Animal model studies have shown that calorie restriction (CR) may promote longevity pathways, but given the difficult application of CR in humans, research is investigating the use of CR-mimetic substances capable of producing the same effect. These include some phytonutrients such as oleuropein, hydroxytyrosol, epigallo-catechin-gallate, fisetin, quercetin, and curcumin and minerals such as magnesium and selenium. Some of them also have senolytic effects, which promote the apoptosis of defective cells that accumulate over the years (senescent cells) and disrupt normal metabolism. In this article, we review the properties of these natural elements that can promote a longer and healthier life.

Chrononutrition-When We Eat Is of the Essence in Tackling Obesity

Obesity is a chronic and relapsing public health problem with an extensive list of associated comorbidities. The worldwide prevalence of obesity has nearly tripled over the last five decades and continues to pose a serious threat to wider society and the wellbeing of future generations. The pathogenesis of obesity is complex but diet plays a key role in the onset and progression of the disease. The human diet has changed drastically across the globe, with an estimate that approximately 72% of the calories consumed today come from foods that were not part of our ancestral diets and are not compatible with our metabolism. Additionally, multiple nutrient-independent factors, e.g., cost, accessibility, behaviours, culture, education, work commitments, knowledge and societal set-up, influence our food choices and eating patterns. Much research has been focused on 'what to eat' or 'how much to eat' to reduce the obesity burden, but increasingly evidence indicates that 'when to eat' is fundamental to human metabolism. Aligning feeding patterns to the 24-h circadian clock that regulates a wide range of physiological and behavioural processes has multiple health-promoting effects with anti-obesity being a major part. This article explores the current understanding of the interactions between the body clocks, bioactive dietary components and the less appreciated role of meal timings in energy homeostasis and obesity.

Mitochondrial Stress in Metabolic Inflammation: Modest Benefits and Full Losses

Energy intake and metabolic balance are the pillars of health preservation. Overnutrition causes nonspecific, persistently low inflammatory state known as metabolic inflammation. This condition contributes to the pathophysiology of various metabolic disorders, such as atherosclerosis, obesity, diabetes mellitus, and metabolic syndrome. The mitochondria maintain the balance of energy metabolism. Excessive energy stress can lead to mitochondrial dysfunction, which promotes metabolic inflammation. The inflammatory environment further impairs mitochondrial function. Accordingly, excellent organism design keeps the body metabolically healthy in the context of mitochondrial dysfunction, and moderate mitochondrial stress can have a beneficial effect. This review summarises the research progress on the multifaceted characterisation of mitochondrial dysfunction and its role in metabolic inflammation.

The mitochondrial unfolded protein response (UPRmt) protects against osteoarthritis

The mitochondrial unfolded protein response (UPR^mt) is a mitochondrial-to-nuclear signaling pathway that is activated to maintain mitochondrial function when there is an accumulation of misfolded proteins within mitochondria. Mitochondrial function is essential for chondrocyte homeostasis, and mitochondrial dysfunction is a characteristic of osteoarthritis (OA). However, the role of the UPR^mt in OA remains unclear. In the present study, the level of the UPR^mt was examined in primary mouse chondrocytes subjected to different stresses and in the articular cartilage of OA model mice and OA patients. The relationship between UPR^mt activation and OA progression was studied. The UPR^mt was induced in primary mouse chondrocytes subjected to diverse stresses and in the cartilage of OA mice. Enhancement of the UPR^mt with nicotinamide riboside (NR) significantly improved mitochondrial function, reduced chondrocyte death, attenuated OA pain, and ameliorated OA progression, and the protective effects decreased significantly in chondrocyte-specific Atf5 knockout (ATF5^f/fCol2a1-CreER^T2) mice. UPR^mt induction was also identified in the articular cartilage of OA patients and was associated with reduced chondrocyte death, less severe hip pain, and lower levels of inflammation in synovial fluid. These findings identify the induction of the UPR^mt in primary mouse chondrocytes exposed to pathological stresses and in the articular cartilage of OA model mice and OA patients. Enhancement of the UPR^mt ameliorates OA progression, suggesting that the UPR^mt exerts a protective effect against OA and may be a potential diagnostic and therapeutic strategy for OA.

Lactiplantibacillus plantarum fermented barley extracts ameliorate high-fat-diet-induced muscle dysfunction via mitophagy

BACKGROUND

A reduced level of fatty acid oxidation (FAO) by skeletal muscle leads to the accumulation of intermuscular fat (IMF), which is linked to impaired exercise capacity. Previously, we have reported that Lactiplantibacillus plantarum fermented barley extract (LFBE) has effective anti-obesity properties. In this study, the effects of LFBE on muscle were investigated.

RESULTS

LFBE improved running endurance and muscle strength, which was caused by the elevation of FAO in muscle. In addition, LFBE renovated muscle regeneration through the upregulation of paired box 7 and myogenic differentiation 1 expression avoiding the injury of skeletal muscle fibers. Furthermore, total polyphenol isolated from LFBE (FTP) reinforced mobility and showed a significant protective effect on maintaining muscle fiber morphogenesis in Caenorhabditis elegans. Transmission electron microscope observation suggested FTP induced mitophagy in C. elegans body wall muscle, which was strongly connected with enhanced FAO in mitochondria.

CONCLUSIONS

Our findings highlighted the beneficial bioactivities of FTP and its potential application for stimulating mitophagy and muscle function in obese individuals. © 2022 Society of Chemical Industry.

Melatonin ameliorates diabetic hyperglycaemia-induced impairment of Leydig cell steroidogenic function through activation of SIRT1 pathway

BACKGROUND

Diabetes mellitus (DM)-related complications are important health problems worldwide. The underlying mechanisms for diabetic male subfertility/infertility are considerably complicated and need to be unveiled for therapeutic intervention. Melatonin treatment was investigated to assess the beneficial effects on injured steroidogenic function in DM due to its regulatory roles in mitochondria and autophagy.

METHODS

Diabetic hyperglycaemia was induced in rats injected with streptozotocin (STZ, 55 mg/kg/d) or simulated in TM3 Leydig cell line cultured with medium containing 30 mM D-glucose. Then, diabetic rats or the TM3 cells under high glucose were treated with melatonin. The diabetic rats were randomly divided into diabetes mellitus group (DM group), insulin treatment group (DM + INS group) and melatonin treatment group (DM + MT group). The TM3 Leydig cells were divided into a normal glucose control group (NG group), a high glucose treatment group (HG group), and a melatonin treatment group (HG + MT group). Then, Sirt1 (silent mating type information regulation 2 homologue) 1 expression was knocked down by siRNA.

RESULTS

The results showed that hyperglycaemia induced a decline in steroidogenesis, accompanied by autophagy defects, mitochondrial dysfunction and oxidative stress, in rats in the DM group or TM3 Leydig cells in the HG group. Furthermore, reduced SIRT1 expression levels and hyperacetylation were found in Leydig cells of DM group. Melatonin treatment ameliorated hyperglycaemia-induced impairment of Leydig cell function with simultaneous stimulation of 5'-adenosine monophosphate activated protein kinase (AMPK)/SIRT1 activity and the expression of autophagy-related genes. With regards to mitochondrial function, it promoted mitochondrial biogenesis with elevated PGC-1α, NRF1 and mtTFA, improved mitochondrial morphology, increased BNIP3L-related mitophagy and alleviated oxidative stress. Further results revealed that knockdown of Sirt1 in Leydig cells prevented the protective effects provided by melatonin against high glucose treatment, and interestingly, neutralization of reactive oxygen species (ROS) by N-acetyl-L-cysteine pretreatment abolished the stimulatory effect of melatonin on AMPK/SIRT1 activity in Leydig cells and prevented the induction of autophagy and mitochondrial biogenesis in the context of high glucose, indicating that modulation of SIRT1 pathway by melatonin was closely linked to ROS levels and oxidative stress.

CONCLUSIONS

These findings suggest that SIRT1 pathway plays essential roles in the pleiotropic actions of melatonin on Leydig cells and in the prevention of hyperglycaemia-induced steroidogenic dysfunction. The stimulatory action of melatonin on SIRT1 pathway is related to oxidative stress and its antioxidant property. Our data provide new evidence for the relationship of melatonin and SIRT1 pathway in the context of hyperglycaemia, and melatonin as a combination therapy may be useful to combat DM-related complications, especially male reproductive system injury.

Discovery of Therapeutics Targeting Oxidative Stress in Autosomal Recessive Cerebellar Ataxia: A Systematic Review

Autosomal recessive cerebellar ataxias (ARCAs) are a heterogeneous group of rare neurodegenerative inherited disorders. The resulting motor incoordination and progressive functional disabilities lead to reduced lifespan. There is currently no cure for ARCAs, likely attributed to the lack of understanding of the multifaceted roles of antioxidant defense and the underlying mechanisms. This systematic review aims to evaluate the extant literature on the current developments of therapeutic strategies that target oxidative stress for the management of ARCAs. We searched PubMed, Web of Science, and Science Direct Scopus for relevant peer-reviewed articles published from 1 January 2016 onwards. A total of 28 preclinical studies fulfilled the eligibility criteria for inclusion in this systematic review. We first evaluated the altered cellular processes, abnormal signaling cascades, and disrupted protein quality control underlying the pathogenesis of ARCA. We then examined the current potential therapeutic strategies for ARCAs, including aromatic, organic and pharmacological compounds, gene therapy, natural products, and nanotechnology, as well as their associated antioxidant pathways and modes of action. We then discussed their potential as antioxidant therapeutics for ARCAs, with the long-term view toward their possible translation to clinical practice. In conclusion, our current understanding is that these antioxidant therapies show promise in improving or halting the progression of ARCAs. Tailoring the therapies to specific disease stages could greatly facilitate the management of ARCAs.

Molecular and metabolic effects of extra-virgin olive oil on the cardiovascular gene signature in rodents

BACKGROUND AND AIMS

Overweight and obesity are major risk factors for degenerative diseases, including cardiometabolic disorders and cancer. Research on fat and fatty acids' type is attracting less attention than that on carbohydrates. High adherence to a Mediterranean diet is associated with a better prognosis. One characteristic of the Mediterranean diet is extra-virgin olive oil (EVOO) as the foremost source of dietary fat. EVOO is different from other vegetable oils because it contains peculiar "minor" components, mainly phenolic in nature. Even though olive oil is highly caloric, unrestricted use of olive oil in the PREDIMED trial did not result in weight gain. We sought to study the effects of EVOO in an appropriate mouse model of increased body weight. Furthermore, we explored the biochemical and metabolomic responses to EVOO consumption.

METHODS AND RESULTS

C57BL/6N male mice were weight-matched and fed ad libitum with the following diets, for 16 weeks: 1) saturated fatty acid diet (SFA) or 2) extra-virgin olive oil diet (EVOO), a custom-prepared diet, isocaloric compared to SFA, in which 82% of fat was replaced by high (poly)phenol EVOO. We evaluated glucose homeostasis, serum biochemistry and plasma metabolomics, in addition to cardiac and hepatic gene profile, and mitochondrial respiration rate.

CONCLUSION

Replacing saturated fatty acids (e.g. lard) with EVOO translates into moderate yet beneficial cardiometabolic and hepatic effects. Future research will further clarify the mechanisms of action of EVOO (poly)phenols and their role in a balanced diet.

Systematically Exploring the Chemical Ingredients and Absorbed Constituents of Polygonum capitatum in Hyperuricemia Rat Plasma Using UHPLC-Q-Orbitrap HRMS

Polygonum capitatum as an ethnic medicine has been used to treat urinary tract infections, pyelonephritis and urinary calculi. In our previous study, P. capitatum was found to have anti-hyperuricemia effects. Nevertheless, the active constituents of P. capitatum for treating hyperuricemia were still unclear. In this study, an ultra-high-performance liquid chromatography coupled to quadrupole/orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) was used to comprehensively detect the chemical ingredients of P. capitatum and its absorbed constituents in the plasma of hyperuricemia rats for the first time. Xcalibur 3.0 and Compound Discoverer 2.0 software coupled to mzCloud and ChemSpider databases were utilized for qualitative analysis. A total of 114 chemical components including phenolics, flavonoids, tannins, phenylpropanoids, amino acids, amides and others were identified or tentatively characterized based on the exact mass, retention time and structural information. Compared to the previous P. capitatum study, an additional 66 different components were detected. Moreover, 68 related xenobiotics including 16 prototype components and 52 metabolites were found in the plasma of hyperuricemia rats. The metabolic pathways included ring fission, hydrolysis, decarboxylation, dehydroxylation, methylation, glucuronidation and sulfation. This work may provide important information for further investigation on the active constituents of P. capitatum and their action mechanisms for anti-hyperuricemia effects.