Linking biomarkers of oxidative stress and disease with flavonoid consumption: From experimental models to humans

Advances in Leaf Plant Bioactive Compounds: Modulation of Chronic Inflammation Related to Obesity

Over the years, there has been a tendency for an increase in global obesity. The World Health Organization's (WHO) 2024 report states that in 2019, more than one billion people were obese, and this condition was responsible for five million deaths, being that obesity is more prevalent among adults compared to adolescents and children. Obesity is a chronic disease characterized by alterations in adipose tissue. When excessive food is consumed and energy expenditure is low, adipose tissue undergoes hypertrophy and hyperplasia. This process activates B cells and induces the transition of anti-inflammatory M2-like macrophages into pro-inflammatory M1-like macrophages. B cells, acting as inflammatory mediators, stimulate pro-inflammatory CD8+ T cells, and promote macrophage infiltration into tissues. This condition triggers inflammation, increases oxidative stress, and ultimately leads to cellular death. During inflammation, an increase of pro-inflammatory cytokines occurs along with a decrease of anti-inflammatory cytokines. By contrast, the increase of oxidative stress is related to an increase of reactive oxygen species (ROS), oxidation of biomolecules, and a decrease in antioxidants. This mechanism for obesity can be mitigated through several healthy lifestyle changes, primarily including regular physical activity and healthy eating. These factors help reduce pro-inflammatory mediators and ROS, lowering inflammation and oxidative stress. Therefore, this review article focuses on studying the bioactive compounds present in the edible leaves of Annona cherimola Mill., Ipomoea batata (L.) Poir., Colocasia esculenta (L.) Schott, Eriobotrya japonica, Cymbopogon citratus, Psidium guajava (L.), and Smallanthus sonchifolius to evaluate their effects on the mechanisms involved in obesity.

(-)-Epicatechin Rescues Memory Deficits by Activation of Autophagy in a Mouse Model of Tauopathies

In tauopathies, defects in autophagy-lysosomal protein degradation are thought to contribute to the abnormal accumulation of aggregated tau. Recent studies have shown that (-)-Epicatechin (Epi), a dietary flavonoid belonging to the flavan-3-ol subgroup, improves blood flow, modulates metabolic profiles, and prevents oxidative damage. However, less research has explored the effects of Epi on tauopathies. Here, we found that Epi rescued cognitive deficits in P301S tau transgenic mice, a model exhibiting characteristics of tauopathies like frontotemporal dementia and Alzheimer's disease, and attenuated tau pathology through autophagy activation. Proteomic and biochemical analyses revealed that P301S mice exhibit deficits in autophagosome formation via modulating mTOR, consequently inhibiting autophagy. Epi inhibited the mTOR signaling pathway to promote autophagosome formation, which is essential for the clearance of tau aggregation. By using chloroquine (CQ) to inhibit autophagy in vivo, we further confirmed that Epi induced tau degradation via the autophagy pathway. Lastly, Epi administration was also found to improve cognition by reversing spine decrease and neuron loss, as well as attenuating neuroinflammation. Our findings suggest that Epi promoted tau clearance by activating autophagy, indicating its potential as a promising therapeutic candidate for tauopathies.

Oral Antioxidant and Lutein/Zeaxanthin Supplements Slow Geographic Atrophy Progression to the Fovea in Age-Related Macular Degeneration

PURPOSE

To determine whether oral micronutrient supplementation slows geographic atrophy (GA) progression in age-related macular degeneration (AMD).

DESIGN

Post hoc analysis of Age-Related Eye Disease Study (AREDS) and AREDS2, multicenter randomized placebo-controlled trials of oral micronutrient supplementation, each with 2 × 2 factorial design.

PARTICIPANTS

A total of 392 eyes (318 participants) with GA in AREDS and 1210 eyes (891 participants) with GA in AREDS2.

METHODS

The AREDS participants were randomly assigned to oral antioxidants (500 mg vitamin C, 400 IU vitamin E, 15 mg β-carotene), 80 mg zinc, combination, or placebo. The AREDS2 participants were randomly assigned to 10 mg lutein/2 mg zeaxanthin, 350 mg docosahexaenoic acid/650 mg eicosapentaenoic acid, combination, or placebo. Consenting AREDS2 participants were also randomly assigned to alternative AREDS formulations: original; no beta-carotene; 25 mg zinc instead of 80 mg; both.

MAIN OUTCOME MEASURES

(1) Change in GA proximity to central macula over time and (2) change in square root GA area over time, each measured from color fundus photographs at annual visits and analyzed by mixed-model regression according to randomized assignments.

RESULTS

In AREDS eyes with noncentral GA (n = 208), proximity-based progression toward the central macula was significantly slower with randomization to antioxidants versus none, at 50.7 μm/year (95% confidence interval [CI], 38.0-63.4 μm/year) versus 72.9 μm/year (95% CI, 61.3-84.5 μm/year; P = 0.012), respectively. In AREDS2 eyes with noncentral GA, in participants assigned to AREDS antioxidants without β-carotene (n = 325 eyes), proximity-based progression was significantly slower with randomization to lutein/zeaxanthin versus none, at 80.1 μm/year (95% CI, 60.9-99.3 μm/year) versus 114.4 μm/year (95% CI, 96.2-132.7 μm/year; P = 0.011), respectively. In AREDS eyes with any GA (n = 392), area-based progression was not significantly different with randomization to antioxidants versus none (P = 0.63). In AREDS2 eyes with any GA, in participants assigned to AREDS antioxidants without β-carotene (n = 505 eyes), area-based progression was not significantly different with randomization to lutein/zeaxanthin versus none (P = 0.64).

CONCLUSIONS

Oral micronutrient supplementation slowed GA progression toward the central macula, likely by augmenting the natural phenomenon of foveal sparing.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Epicatechin Influence on Biochemical Modification of Human Erythrocyte Metabolism and Membrane Integrity

Red blood cells (RBCs) are the main cells of the blood, perform numerous functions within the body and are in continuous contact with endogenous and exogenous molecules. In this context, the study aims to investigate the effect of epicatechin (EC) (flavan-3-ols) on the erythrocytes, analyzing the protective effect of the molecule and the action exerted on metabolism and RBC membrane. The effect of EC on RBC viability has been evaluated through the change in hemolysis and methemoglobin, assessing caspase 3 activity and performing a cytofluorometric analysis. Next, the impact of the molecule on RBC metabolism was assessed by measuring anion flux kinetics, ATP production, and phosphatase activity. Finally, an evaluation of the potential protection against different stressors was performed. Our results show no detrimental effects of EC on RBCs (no change in hemolysis or methemoglobin and no caspase 3 activation recorded); rather, a protective effect was recorded given the reduction in hemolysis induced by hydrogen peroxide treatment and temperature increase. The increase in anion exchange and intracellular ATP values, with the inhibition of phosphatase PTP1B activity, highlights several biochemical alterations induced by EC. The present results contribute to clarifying the influence of EC on RBCs, confirming the beneficial effects of catechins.

Nobiletin protects against alcohol-induced mitochondrial dysfunction and liver injury by regulating the hepatic NRF1-TFAM signaling pathway

OBJECTIVES

Alcohol and its metabolites, such as acetaldehyde, induced hepatic mitochondrial dysfunction play a pathological role in the development of alcohol-related liver disease (ALD).

METHODS

In this study, we investigated the potential of nobiletin (NOB), a polymethoxylated flavone, to counter alcohol-induced mitochondrial dysfunction and liver injury.

RESULTS

Our findings demonstrate that NOB administration markedly attenuated alcohol-induced hepatic steatosis, endoplasmic reticulum stress, inflammation, and tissue damage in mice. NOB reversed hepatic mitochondrial dysfunction and oxidative stress in both alcohol-fed mice and acetaldehyde-treated hepatocytes. Mechanistically, NOB restored the reduction of hepatic mitochondrial transcription factor A (TFAM) at both mRNA and protein levels. Notably, the protective effects of NOB against acetaldehyde-induced mitochondrial dysfunction and cell death were abolished in hepatocytes lacking Tfam. Furthermore, NOB administration reinstated the levels of hepatocellular NRF1, a key transcriptional regulator of TFAM, which were decreased by alcohol and acetaldehyde exposure. Consistent with these findings, hepatocyte-specific overexpression of Nrf1 protected against alcohol-induced hepatic Tfam reduction, mitochondrial dysfunction, oxidative stress, and liver injury.

CONCLUSIONS

Our study elucidates the involvement of the NRF1-TFAM signaling pathway in the protective mechanism of NOB against chronic-plus-binge alcohol consumption-induced mitochondrial dysfunction and liver injury, suggesting NOB supplementation as a potential therapeutic strategy for ALD.

Identification of Primary Metabolite Profiles Reveals Quality Characteristics of Citrus maxima 'Shatian Yu' from Different Origins

Citrus maxima 'Shatian Yu' displays varying nutritional profiles influenced by its production area. This study evaluated pomelo fruits from four primary and one developing 'Shatian Yu' production area. Notably, 'Shatian Yu' from the Guilin area exhibited higher sugar and alcohol content, suggesting enhanced taste. Principal component analysis and OPLS-DA revealed significant metabolite differences among production areas. In Guilin, variations were observed in a few substances, including sugars, alcohols, and phenolic acids. When compared with Rong City, Guilin showed a decrease in four phenolic acids and an increase in three organic acids, eighteen amino acids, eighteen lipids, and one vitamin. This comprehensive analysis provides valuable insights for the development of 'Shatian Yu' cultivation, highlighting the impact of production areas on fruit quality.

Association between composite dietary antioxidant index and metabolic dysfunction associated steatotic liver disease: result from NHANES, 2017-2020

Background

The development of metabolic dysfunction associated steatotic liver disease (MASLD) has been associated with lipid accumulation, oxidative stress, endoplasmic reticulum stress, and lipotoxicity. The Composite Dietary Antioxidant Index (CDAI) is a comprehensive score representing an individual intake of various dietary antioxidants, including vitamin A, vitamin C, vitamin E, selenium, zinc, and carotenoids. This study investigated the association between CDAI and MASLD.

Materials and methods

Clinical and demographic data, as well as ultrasound transient elastography measurements at baseline, were collected from the National Health and Nutrition Examination Survey 2017-2020 (NHANES 2017-2020). The controlled attenuation parameter was utilized to diagnose the presence of hepatic steatosis and to categorize individuals into those with and without MASLD. Liver stiffness was measured by ultrasound transient elastography, and subjects were classified as those with and without advanced liver fibrosis.

Results

This study included 5,884 adults, of whom 3,433 were diagnosed with MASLD, resulting in a weighted prevalence of 57.3%. After adjusting for covariates, the odds ratios for MASLD were 0.96 (95% CI: 0.82, 1.12) in the second quartile, 0.80 (95% CI: 0.68, 0.95) in the third quartile and 0.60 (95% CI: 0.49, 0.73) in the fourth quartile, respectively. CDAI, however, was not significantly associated with advanced liver fibrosis.

Conclusion

These findings suggested that scores on the CDAI were linearly and negatively associated with the prevalence of MASLD in the United States adults.

Dietary flavonoids modulate the gut microbiota: A new perspective on improving autism spectrum disorder through the gut-brain axis

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with an unknown etiology. It is associated with various factors and causes great inconvenience to the patient's life. The gut-brain axis (GBA), which serves as a bidirectional information channel for exchanging information between the gut microbiota and the brain, is vital in studying many neurodegenerative diseases. Dietary flavonoids provide anti-inflammatory and antioxidant benefits, as well as regulating the structure and function of the gut microbiota. The occurrence and development of ASD are associated with dysbiosis of the gut microbiota. Modulation of gut microbiota can effectively improve the severity of ASD. This paper reviews the links between gut microbiota, flavonoids, and ASD, focusing on the mechanism of dietary flavonoids in regulating ASD through the GBA.

Ethnomedicinal Importance of Patuletin in Medicine: Pharmacological Activities and Analytical Aspects

BACKGROUND

Plant-derived bioactive molecules have been a major source of therapeutic agents for human and veterinarian purposes. Different traditional medicine system across the globe had relied on natural resources to meet their demand of healthcare. Still in modern world, pharmaceutical industries look for phytochemicals to develop new drugs. The current review explores patuletin, a flavonoid for its diverse reported pharmacological activities along with its analytical techniques.

METHODS

Scientific data published on patuletin was collected from Scopus, Science Direct, Pubmed, Google, and Google Scholar. The collected data were analyzed and arranged as per specific pharmacological activities performed using in-vitro or in-vivo methods. Analytical methods of patuletin have been presented next to pharmacological activities Results: Available scientific literature indicates patuletin has anti-inflammatory, cytotoxic, genotoxic, hepatoprotective, antiproliferative, antiplatelet, antinociceptive, and antioxidant activity. In addition to these activities, its biological potential on breast cancer, rheumatoid arthritis, aldose reductase, and different types of microorganisms has been also presented in this work. Analytical data on patuletin signified the importance of patuletin for the standardization of herbal products and derived medicine.

CONCLUSION

It may be concluded that patuletin with its diverse biological activities and readily available analytical methods, holds the potential to be translated into a new drug entity.

Beneficial effects of flavonoids on animal models of atherosclerosis: A systematic review and meta-analysis

Atherosclerosis is the main cause of cardiovascular diseases that seriously endanger human health. The existing treatment drugs are effective, but they have some side effects. Accumulating evidence suggests that flavonoids have attracted wide attention due to their multiple cardioprotective effects and fewer side effects. PubMed, Web of Science database, Embase, and Cochrane Library were searched for studies evaluating the effects of flavonoids against atherosclerosis. 119 studies published from August 1954 to April 2023 were included. Random-effects models were performed for synthesis. Compared with the control group, flavonoids significantly reduced longitudinal and cross-sectional plaque area. The findings indicated that flavonoids significantly reduced the concentrations of serum TC, TG, and LDL-C and increased serum HDL-C concentrations. Besides, flavonoids reduced the levels of circulating pro-inflammatory factors, including TNF-α, IL-1β, and IL-6, and increased the serum IL-10 level. This study provides evidence for the potential cardiovascular benefits of flavonoids.

Baicalein mitigates oxidative stress and enhances lifespan through modulation of Wnt ligands and GATA factor: ELT-3 in Caenorhabditis elegans

AIMS

Age predispose individual to major diseases, and the biological processes contributing to aging are currently under intense investigation. Hence, plant-based natural compounds could be a potential target to counteract aging and age-associated diseases. So, the present study aims to investigate the antiaging properties of a natural compound Baicalein (BAI) on C. elegans and to elucidate the pathways or signaling molecules involved.

METHODS

Herein, we investigated the inhibitory effects of BAI on different Wnt ligands of C. elegans and its underlying mechanisms. Moreover, we monitored BAI's antiaging effect on the worms' lifespan and its different aging parameters. We employed different mutant and transgenic C. elegans strains to identify the pathways and transcription factors involved.

KEY FINDINGS

We first showed that BAI could downregulate different Wnt ligands mRNA expressions in C. elegans, resulting in enhanced expression of GATA transcription factor ELT-3 and antiaging gene Klotho. On further evaluation, it was observed that BAI could enhance the worm's lifespan via ELT-3 and SKN-1 transcription factors, whereas, for the protection of worms against external oxidative stress, both ELT-3 and DAF-16 transcription factors were involved. Moreover, sensitive aging parameters of worms, including lipofuscin and ROS accumulation, and the declined physiological and mechanical functions observed in aged worms were ameliorated by BAI.

SIGNIFICANCE

This study highlighted BAI as a promising antiaging compound. This study also revealed the Wnt inhibitory potential of BAI with future implications for pharmacological target of age-associated diseases with aberrant activation of the Wnt pathway.

Role of polyphenolic compounds and their nanoformulations: a comprehensive review on cross-talk between chronic kidney and cardiovascular diseases

Chronic kidney disease (CKD) affects a huge portion of the world's population and frequently leads to cardiovascular diseases (CVDs). It might be because of common risk factors between chronic kidney disease and cardiovascular diseases. Renal dysfunction caused by chronic kidney disease creates oxidative stress which in turn leads to cardiovascular diseases. Oxidative stress causes endothelial dysfunction and inflammation in heart which results in atherosclerosis. It ends in clogging of veins and arteries that causes cardiac stroke and myocardial infarction. To develop an innovative therapeutic approach and new drugs to treat these diseases, it is important to understand the pathophysiological mechanism behind the CKD and CVDs and their interrelationship. Natural phytoconstituents of plants such as polyphenolic compounds are well known for their medicinal value. Polyphenols are plant secondary metabolites with immense antioxidant properties, which can protect from free radical damage. Nowadays, polyphenols are generating a lot of buzz in the scientific community because of their potential health benefits especially in the case of heart and kidney diseases. This review provides a detailed account of the pathophysiological link between CKD and CVDs and the pharmacological potential of polyphenols and their nanoformulations in promoting cardiovascular and renal health.

Verniciflavanol A, a profisetinidin-type-4-arylflavan-3-ol from toxicodendron vernicifluum protects SH-SY5Y cells against H2O2-Induced oxidative stress

Eleven undescribed derivatives of flavan, including flavan-3,4-diols vernicinosides A-H and profisetinidin-type-4-arylflavan-3-ols verniciflavanols A-C, together with eight known compounds were purified from the heartwood of Toxicodendron vernicifluum. The chemical structures of the undescribed compounds were characterized by spectroscopic data interpretation, including NMR (¹H and ¹³C NMR HSQC and HMBC) and HRESIMS analysis. CD data analysis was conducted to assign the absolute configurations of the undescribed compounds and the active compound verniciflavanol A was also confirmed by ECD experiment. The absolute configuration of the sugar moiety was identified by GC analysis of chiral derivatives in the hydrolysate. MTT assay was applied to test these compounds against H₂O₂-induced oxidative stress in human neuroblastoma SH-SY5Y cells. Results found that verniciflavanol A demonstrated the best potential in protecting SH-SY5Y cells against H₂O₂-induced oxidative stress by inhibiting cell apoptosis and attenuate reactive oxygen species (ROS) level and mitochondrial dysfunction. And the underlying mechanism was confirmed to be associated with Nrf2-antioxidant response element signaling and IL-6 cell survival pathways.

Targeted UHPLC-MS Analysis Reveals Disparate Polyphenol Composition and Concentration in Muscadine Grape Supplements with Proportional Antioxidant Activity

Muscadine grape supplements (MGS) with high polyphenol content are a potential therapeutic option to combat oxidative stress; however, the precise identity and concentration of individual phenolics in commercially processed MGSs is not well defined. We probed for 17 phenolic compounds by ultra-high pressure liquid chromatography and mass spectroscopy from distinct lots of four commercially processed MGSs composed of MG seed and/or skin waste products. The total phenolic content (TPC) and antioxidant capacity were highest in a dried water-extract MGS as compared to three ground seed and/or skin products. The TPC was not different between MGS lots from individual companies and remained stable for 3 years without microbial contamination. The extract MGS had the highest concentration of epicatechin, ellagic acid, gallic acid, procyanidin B2, catechin and catechin gallate compared to the other supplements. Only ellagic acid and gallic acid were detected in all four MGSs, while catechin and catechin gallate were below detection in two supplements. Based on gram weight, only the extract MGS prevented the angiotensin II-induced increase in malondialdehyde and 4-hydroxynonenol in rat H9c2 cardiomyocytes as well as upregulated superoxide dismutase and catalase. This study demonstrates that commercial MGSs differ in phenolic composition and concentration, resulting in disparate antioxidant activity.

Flavonoids in vegetables: improvement of dietary flavonoids by metabolic engineering to promote health

Flavonoids are the most abundant polyphenols in plants, and have antioxidant effects as well as other bioactivities (e.g., anti-inflammatory, anti-cancer, anti-allergic, and neuroprotective effects). Vegetables are rich in flavonoids and are indispensable in our daily diet. Moreover, the vegetables as chassis for producing natural products would emerge as a promising means for cost-effective and sustainable production of flavonoids. Understanding the metabolic engineering of flavonoids in vegetables allows us to improve their nutrient composition. In this review, a comprehensive overview of flavonoids in vegetables, including the characterized types and distribution, health-promoting effects, associated metabolic pathways, and applied metabolic engineering are provided. We also introduce breakthroughs in multi-omics approaches that pertain to the elucidation of flavonoids metabolism in vegetables, as well as prospective and potential genome-editing technologies. Based on the varied composition and content of flavonoids among vegetables, dietary suggestions are further provided for human health.

Robust therapeutic effects on COVID-19 of novel small molecules: Alleviation of SARS-CoV-2 S protein induction of ACE2/TMPRSS2, NOX2/ROS, and MCP-1

While new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) constantly emerge to prolong the pandemic of COVID-19, robust and safe therapeutics are in urgent need. During the previous and ongoing fight against the pandemic in China, Traditional Chinese Medicine (TCM) has proven to be markedly effective in treating COVID-19. Among active ingredients of TCM recipes, small molecules such as quercetin, glabridin, gallic acid, and chrysoeriol have been predicted to target viral receptor angiotensin-converting enzyme 2 (ACE2) via system pharmacology/molecular docking/visualization analyses. Of note, endothelial dysfunction induced by oxidative stress and inflammation represents a critical mediator of acute respiratory distress syndrome (ARDS) and multi-organ injuries in patients with COVID-19. Hence, in the present study, we examined whether quercetin, glabridin, gallic acide and chrysoeriol regulate viral receptors of ACE2 and transmembrane serine protease 2 (TMPRSS2), redox modulator NADPH oxidase isoform 2 (NOX2), and inflammatory protein of monocyte chemoattractant protein-1 (MCP-1) in endothelial cells to mediate therapeutic protection against COVID-19. Indeed, quercetin, glabridin, gallic acide and chrysoeriol completely attenuated SARS-CoV-2 spike protein (S protein)-induced upregulation in ACE2 protein expression in endothelial cells. In addition, these small molecules abolished S protein upregulation of cleaved/active form of TMPRSS2, while native TMPRSS2 was not significantly regulated. Moreover, these small molecules completely abrogated S protein-induced upregulation in NOX2 protein expression, which resulted in alleviated superoxide production, confirming their preventive efficacies against S protein-induced oxidative stress in endothelial cells. In addition, treatment with these small molecules abolished S protein induction of MCP-1 expression. Collectively, our findings for the first time demonstrate that these novel small molecules may be used as novel and robust therapeutic options for the treatment of patients with COVID-19, via effective attenuation of S protein induction of endothelial oxidative stress and inflammation.

Flavonoids from Lycium barbarum leaves attenuate obesity through modulating glycolipid levels, oxidative stress, and gut bacterial composition in high-fat diet-fed mice

Traditional herbal therapy made from Lycium barbarum leaves has been said to be effective in treating metabolic diseases, while its exact processes are yet unknown. Natural flavonoids are considered as a secure and reliable method for treating obesity. We thus made an effort to investigate the processes by which flavonoids from L. barbarum leaves (LBLF) reduce obesity. To assess the effectiveness of the intervention following intragastric injection of various dosages of LBLF (50, 100, and 200 mg/kg⋅bw), obese model mice developed via a high-fat diet were utilized. Treatment for LBLF may decrease body weight gain, Lee’s index, serum lipids levels, oxidative stress levels, and hepatic lipids levels. It may also enhance fecal lipids excretion and improve glucose tolerance. Additionally, LBLF therapy significantly restored gut dysfunction brought on by a high-fat diet by boosting gut bacterial diversities and altering the composition of the gut bacterial community by elevating probiotics and reducing harmful bacteria.

Defining roles of specific reactive oxygen species (ROS) in cell biology and physiology

'Reactive oxygen species' (ROS) is a generic term that defines a wide variety of oxidant molecules with vastly different properties and biological functions that range from signalling to causing cell damage. Consequently, the description of oxidants needs to be chemically precise to translate research on their biological effects into therapeutic benefit in redox medicine. This Expert Recommendation article pinpoints key issues associated with identifying the physiological roles of oxidants, focusing on H₂O₂ and O₂^.-. The generic term ROS should not be used to describe specific molecular agents. We also advocate for greater precision in measurement of H₂O₂, O₂^.- and other oxidants, along with more specific identification of their signalling targets. Future work should also consider inter-organellar communication and the interactions of redox-sensitive signalling targets within organs and whole organisms, including the contribution of environmental exposures. To achieve these goals, development of tools that enable site-specific and real-time detection and quantification of individual oxidants in cells and model organisms are needed. We also stress that physiological O₂ levels should be maintained in cell culture to better mimic in vivo redox reactions associated with specific cell types. Use of precise definitions and analytical tools will help harmonize research among the many scientific disciplines working on the common goal of understanding redox biology.

(-)-Epicatechin Reduces Neuroinflammation, Protects Mitochondria Function, and Prevents Cognitive Impairment in Sepsis-Associated Encephalopathy

Sepsis-associated encephalopathy is a common neurological complication of sepsis. Despite advances in pathological and diagnostic investigations, its treatment remains a major challenge. In sepsis-associated encephalopathy, neuroinflammatory overactivation and mitochondrial damage are thought to contribute to cognitive and behavioral impairments. In this study, we found that administration of (−)-Epicatechin, a dietary flavonoid of the flavan-3-ol subgroup, improves memory deficits and behavior performance by ameliorating neuroinflammation, regulating mitochondria function, enhancing synaptic plasticity, and reducing neuronal loss in a mouse model of lipopolysaccharide-induced sepsis. We further show that the AMPK signaling pathway might be among the mechanisms involved in the beneficial memory effects. Our data demonstrated the potential of (−)-Epicatechin as a new drug candidate for the treatment of sepsis-associated cognitive impairment by targeting AMPK.

A randomized placebo-controlled cross-over study on the effects of anthocyanins on inflammatory and metabolic responses to a high-fat meal in healthy subjects

This study investigated the effects of supplementation with a cyanidin- and delphinidin-rich extract (CDRE) on the postprandial dysmetabolism, inflammation, and redox and insulin signaling, triggered by the consumption of a high fat meal (HFM) in healthy individuals. Participants (n = 25) consumed a 1026-kcal HFM simultaneously with either the CDRE providing 320.4 mg of anthocyanins (90% cyanidin and delphinidin) or placebo. Diets were randomly assigned in a double blind, placebo-controlled crossover design. Blood was collected prior to (fasted, time 0), and for 5 h after meal consumption; plasma, serum, and peripheral blood mononuclear cells (PBMC) were isolated. AC metabolites were detected in serum as early as 30 min after CDRE consumption. The CDRE mitigated HFM-induced endotoxemia, reducing increases in plasma LPS and LPS-binding protein. The CDRE also reduced other events associated with HFM-triggered postprandial dysmetabolism including: i) plasma glucose and triglyceride increases; ii) TNFα and NOX4 upregulation in PBMC; and iii) JNK1/2 activation in PBMC. The CDRE did not significantly affect HFM-mediated increases in plasma insulin, GLP-1, GLP-2, GIP, and LDL- and HDL-cholesterol, and IKK phosphorylation in PBMC. In summary, dietary AC, i.e. cyanidin and delphinidin, exerted beneficial actions against unhealthy diets by modulating the associated postprandial dysmetabolism, endotoxemia, alterations of glycemia and lipidemia, and redox and insulin signaling.

Curcumin Mitigates TNFα-Induced Caco-2 Cell Monolayer Permeabilization Through modulation of NF-κB, ERK1/2 and JNK Pathways

SCOPE

This work studied the capacity of curcumin to inhibit TNFα-induced inflammation, oxidative stress, and loss of intestinal barrier integrity, characterizing the underlying mechanisms.

METHODS AND RESULTS

Caco-2 cell monolayers were incubated with TNFα (10 ng/ml), in the absence or presence of curcumin. TNFα caused an increase in interleukin (IL)-6 and IL-8 release which was inhibited by curcumin in a dose-dependent manner (IC₅₀ = 3.4 μM for IL-6). Moreover, TNFα led to: i) increased ICAM-1 and NLRP3 expression; ii) increased cell monolayer permeability and decreased levels of tight junction proteins; iii) increased cellular and mitochondrial oxidant production; iv) decreased mitochondrial membrane potential and complex I-III activity; v) activation of redox-sensitive pathways, i.e., NF-κB, ERK1/2 and JNK; and vi) increased MLCK expression and phosphorylation levels of MLC. Curcumin (2-8 μM) inhibited all these TNFα-triggered undesirable outcomes, mostly showing dose-dependent effects.

CONCLUSION

The inhibition of NF-κB, ERK1/2 and JNK activation could be in part involved in the capacity of curcumin to mitigate intestinal inflammation, oxidant production, activation of redox-sensitive pathways, and prevention of monolayer permeabilization. These results support an action of dietary curcumin in sustaining gastrointestinal tract physiology. This article is protected by copyright. All rights reserved.

Supplementation with cyanidin and delphinidin mitigates high fat diet-induced endotoxemia and associated liver inflammation in mice

Consumption of high fat diets (HFD) and the associated metabolic endotoxemia can initiate liver inflammation and lipid deposition that with time can progress to non-alcoholic fatty liver disease (NAFLD). We previously observed that 14 weeks supplementation with the anthocyanidins cyanidin and delphinidin mitigated HFD-induced metabolic endotoxemia and liver insulin resistance, steatosis, inflammation and oxidative stress. This work investigated if a 4-week supplementation of mice with a cyanidin- and delphinidin-rich extract (CDRE) could mitigate or reverse HFD (60% calories from lard fat)-induced liver steatosis and inflammation. After a first 4-weeks period on the HFD, mice showed increased endotoxemia and activation of liver proinflammatory signaling cascades. Supplementation with CDRE between weeks 4 and 8 did not mitigate liver steatosis or the altered lipid and glucose plasma levels. However, CDRE supplementation reverted HFD-induced metabolic endotoxemia, in parallel with the mitigation of the overexpression of hepatic TLR2 and TLR4, and of the activation of: (i) NF-κB, (ii) AP-1 and upstream mitogen-activated kinases p38 and ERK1/2, and (iii) HIF-1. Thus, even a short-term consumption of cyanidin and delphinidin could help mitigate the adverse consequences, i.e. metabolic endotoxemia and associated liver inflammation, triggered by the regular consumption of diets rich in fat.

Revisiting the Oxidation of Flavonoids: Loss, Conservation or Enhancement of Their Antioxidant Properties

Flavonoids display a broad range of health-promoting bioactivities. Among these, their capacity to act as antioxidants has remained most prominent. The canonical reactive oxygen species (ROS)-scavenging mode of the antioxidant action of flavonoids relies on the high susceptibility of their phenolic moieties to undergo oxidation. As a consequence, upon reaction with ROS, the antioxidant capacity of flavonoids is severely compromised. Other phenol-compromising reactions, such as those involved in the biotransformation of flavonoids, can also markedly affect their antioxidant properties. In recent years, however, increasing evidence has indicated that, at least for some flavonoids, the oxidation of such residues can in fact markedly enhance their original antioxidant properties. In such apparent paradoxical cases, the antioxidant activity arises from the pro-oxidant and/or electrophilic character of some of their oxidation-derived metabolites and is exerted by activating the Nrf2–Keap1 pathway, which upregulates the cell’s endogenous antioxidant capacity, and/or, by preventing the activation of the pro-oxidant and pro-inflammatory NF-κB pathway. This review focuses on the effects that the oxidative and/or non-oxidative modification of the phenolic groups of flavonoids may have on the ability of the resulting metabolites to promote direct and/or indirect antioxidant actions. Considering the case of a metabolite resulting from the oxidation of quercetin, we offer a comprehensive description of the evidence that increasingly supports the concept that, in the case of certain flavonoids, the oxidation of phenolics emerges as a mechanism that markedly amplifies their original antioxidant properties. An overlooked topic of great phytomedicine potential is thus unraveled.

Theaflavin 3, 3'-Digallate Delays Ovarian Aging by Improving Oocyte Quality and Regulating Granulosa Cell Function

Ovarian aging refers to the gradual decline of ovarian function with increasing physiological age, manifested as decreased ovarian reserve, elevated aging-related markers, and reduced oocyte quality. With a declining female fertility and a growing aging population, it is urgent to delay ovarian aging to maintain fertility and improve the life quality of women. Theaflavin 3, 3′-digallate (TF3) is a naturally bioactive polyphenol compound extracted from black tea, and its antioxidant properties play an important role in maintaining human health and delaying aging; however, the effects of TF3 on female reproduction and ovarian function are not yet clear. Here, we show that TF3 can preserve primordial follicle pool, partially restore the estrous cycle, and increase the offspring number of aged mice. Meanwhile, TF3 gavage increased the number of oocytes retrieved, decreased the level of reactive oxygen species, increased the level of glutathione, and decreased the abnormal rate of oocyte spindle after ovulation induction. Moreover, TF3 inhibited human granulosa cell apoptosis and improved their antioxidative stress ability. High-throughput sequencing and small-molecule-targeted pharmacological prediction show that TF3 affects multiple pathways and gene expression levels, mainly involved in reproductive and developmental processes. It may also affect cellular function by targeting mTOR to regulate the autophagic pathway, thereby delaying the process of ovarian aging. This study shows that TF3 can be used as a potential dietary supplement to protect ovary function from aging and thereby improving the life quality of advanced-age women.