Anthocyanins and Flavanones Are More Bioavailable than Previously Perceived: A Review of Recent Evidence

Small Phenolic Metabolites at the Nexus of Nutrient Transport and Energy Metabolism

Over time, human metabolism evolved to accommodate the challenges and benefits of plant foods that contain high amounts of carbohydrates and polyphenols. The latter are typically metabolized into small phenolic metabolites, including phenolic acids and their endogenous and microbial derivatives, that influence interconnected metabolic pathways involved in nutrient transport, energy metabolism, and neurotransmitter balance. Unlike other natural products, their biological effects arise from weak interactions with multiple molecular pathways rather than a single high-affinity receptor, making them versatile regulators of metabolic health. These compounds also modulate glucose transporters and carbohydrate metabolism, playing a crucial role in postprandial glucose and insulin responses. This review addresses the critical role of phenolic metabolites in metabolic health, with a focus on glucose homeostasis, insulin sensitivity, and carbohydrate metabolism. Incorporating polyphenols and phenolic acids into dietary strategies offers significant potential for improving insulin sensitivity, reducing metabolic disorder risks, and promoting whole-body glucose homeostasis. Furthermore, understanding how phenolic metabolites interact with metabolic pathways is essential for developing future effective nutritional strategies to support metabolic health.

RG-I pectic polysaccharides and hesperidin synergistically modulate gut microbiota: An in vitro study targeting the proportional relationship

In this study, we investigated how different proportions blends of Rhamnogalacturonan-I pectic polysaccharides and hesperidin impact the gut microbiota and metabolites using an in vitro simulated digestion and fermentation model. The results indicated that both of them could modulate the gut microbiota and produce beneficial metabolites. However, their blends in particular proportions (such as 1:1) exhibited remarkable synergistic effects on modulating the intestinal microenvironment, surpassing the effects observed with individual components. Specifically, these blends could benefit the host by increasing short-chain fatty acids production (such as acetate), improving hesperidin bioavailability, producing more metabolites (such as hesperetin, phenolic acids), and promoting the growth of beneficial bacteria. This synergistic and additive effect was inseparable from the role of gut microbiota. Certain beneficial bacteria, such as Blautia, Faecalibacterium, and Prevotella, exhibited strong preferences for those blends, thereby contributing to host health through participating in carbohydrate and flavonoid metabolism.

Dose-dependent effects of anthocyanin-rich extracts on obesity-induced inflammation and gut microbiota modulation

Obesity and its associated inflammatory state pose a significant health burden. Anthocyanins, bioactive compounds found in fruits and vegetables, have garnered interest in their potential to attenuate these conditions. Understanding the dose-dependent response of anthocyanins is essential for optimizing their therapeutic potential in preventing and managing obesity. This comprehensive review explores the current knowledge on the dose-dependent effects of anthocyanins on obesity in both human and animal models, analyzing the structure and mechanism of absorption of these compounds. The article also highlights the diverse mechanisms underlying anthocyanin action, the symbiosis between anthocyanins and gut microbiota impacting metabolite production, influencing diverse health outcomes, modulating cytokines, and activating anti-inflammatory pathways. Additionally, their impact on energy metabolism and lipid regulation is discussed, highlighting potential contributions to weight management through AMPK and PPARγ pathways. Despite promising results, dose-dependent effects are fundamental considerations, with some studies indicating less favorable outcomes at higher doses. Future research should focus on optimizing dosages, accounting for individual responses, and translating findings into effective clinical applications for obesity management.

Yu-Xue-Bi capsule ameliorates aggressive synovitis and joint damage in rheumatoid arthritis via modulating the SUCNR1/HIF-1α/TRPV1 axis

BACKGROUND

Specific treatment for rheumatoid arthritis (RA) is still an unmet need. Yu-Xue-Bi (YXB) capsule effectively treats RA with blood stasis syndrome (BS). However, its mechanism remains unclear.

PURPOSE

Exploring and elucidating the therapeutic effect and pharmacological mechanism of YXB capsule in treating RA.

METHODS

This study identified differentially expressed genes (DEGs) in patients with RA and BS compared to healthy controls using clinical transcriptomics data. Clinical symptoms of RA and BS, and the related genes were collected from the SoFDA and HPO databases. Candidate bioactive constituents in YXB were identified via UPLC-QTOF/MS and evaluated using ADMET rules. Putative targets were predicted, and a network linking disease-related DEGs and drug targets was constructed. Key targets were screened utilizing random walk-with-restart (RWR) algorithms and verified through experiments using rat models of collagen-induced arthritis with BS (CIA-BS model) in vivo.

RESULTS

We found 1220 DEGs along with 976 clinical symptom-related genes, as RA with BS-related genes. Chemical profiling identified 193 YXB constituents, with 98 meeting optimal ADMET criteria. We predicted 459 putative targets for these constituents. Network calculations screened 209 key targets, 129 RA with BS-related genes and 92 YXB targets involved in immune inflammation, blood stagnation, and hyperalgesia imbalance. Notably, the SUCNR1/HIF-1α/TRPV1 axis was enriched by YXB targets against RA with BS. Experimentally, YXB inhibited inflamed joint deterioration, including synovial inflammation, cartilage damage and bone erosion, relieving mechanical and cold allodynia hyperglasia. It reversed hemorrheology and vascular function in CIA-BS rats, restoring SDHB and eNOS expression, preventing SDHA, SUCNR1 and HIF-1α activation, reducing SUCN, TNF-α and IL-1β production, and TRPV1 and TRPA1 expression.

CONCLUSION

Our data support YXB's therapeutic effects on aggressive RA-BS by modulating the SUCNR1/HIF-1α/TRPV1 axis.

Metabolism of quercitrin in the colon and its beneficial regulatory effects on gut microbiota

BACKGROUND

Quercitrin is a dietary flavonoid widely found in plants with various physiological activities. However, whether quercitrin alters gut microbiota in vivo is not well understood. The aim of this study was to investigate metabolism of quercitrin in the colon and its regulation on gut microbiota in mice.

RESULTS

Herein, 22 flavonoids related to quercitrin metabolism were identified based on ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS). Gas chromatography and 16S rDNA gene sequencing were used to investigate short-chain fatty acid (SCFA) content and diversity of composition of gut microbiota, respectively. The results showed that quercitrin significantly alters the beta-diversity of the gut microbiota, probiotics such as Akkermansia and Lactococcus were significantly increased, and the production of propanoate, isovalerate and hexanoate of the quercitrin group were enhanced significantly. The Spearman's association analysis provided evidence that Gardnerella and Akkermansia have obvious correlations with most of quercitrin metabolites and SCFAs.

CONCLUSION

Quercitrin and its metabolites in the colon altered the structure of the mice gut microbiota and increased the content of SCFAs. Our experiments provide valuable insights into quercitrin research and application. © 2024 Society of Chemical Industry.

A One-Week Elderberry Juice Intervention Augments the Fecal Microbiota and Suggests Improvement in Glucose Tolerance and Fat Oxidation in a Randomized Controlled Trial

Obesity is a costly and ongoing health complication in the United States and globally. Bioactive-rich foods, especially those providing polyphenols, represent an emerging and attractive strategy to address this issue. Berry-derived anthocyanins and their metabolites are of particular interest for their bioactive effects, including weight maintenance and protection from metabolic aberrations. Earlier findings from small clinical trials suggest modulation of substrate oxidation and glucose tolerance with mediation of prospective benefits attributable to the gut microbiota, but mixed results suggest appropriate anthocyanin dosing poses a challenge. The objective of this randomized, placebo-controlled study was to determine if anthocyanin-dense elderberry juice (EBJ) reproduces glucoregulatory and substrate oxidation effects observed with other berries and if this is mediated by the gut microbiota. Overweight or obese adults (BMI > 25 kg/m2) without chronic illnesses were randomized to a 5-week crossover study protocol with two 1-week periods of twice-daily EBJ or placebo (PL) separated by a washout period. Each treatment period included 4 days of controlled feeding with a 40% fat diet to allow for comparison of measurements in fecal microbiota, meal tolerance testing (MTT), and indirect calorimetry between test beverages. Eighteen study volunteers completed the study. At the phylum level, EBJ significantly increased Firmicutes and Actinobacteria, and decreased Bacteroidetes. At the genus level, EBJ increased Faecalibacterium, Ruminococcaceae, and Bifidobacterium and decreased Bacteroides and lactic acid-producing bacteria, indicating a positive response to EBJ. Supporting the changes to the microbiota, the EBJ treatment significantly reduced blood glucose following the MTT. Fat oxidation also increased significantly both during the MTT and 30 min of moderate physical activity with the EBJ treatment. Our findings confirm the bioactivity of EBJ-sourced anthocyanins on outcomes related to gut health and obesity. Follow-up investigation is needed to confirm our findings and to test for longer durations.

Integrated Metabolomics and Transcriptomics Analyses Reveal the Regulatory Mechanisms of Anthocyanin and Carotenoid Accumulation in the Peel of Coffea arabica

The color of coffee fruits is influenced by several factors, including cultivar, ripening stage, and metabolite composition. However, the metabolic accumulation of pigments and the molecular mechanisms underlying peel coloration during the ripening process of Coffea arabica L. remain relatively understudied. In this study, UPLC-MS/MS-based metabolomics and RNA sequencing (RNA-seq)-based transcriptomics were integrated to investigate the accumulation of anthocyanins and carotenoids in the peel of Coffea arabica at different ripening stages: green peel (GP), green-yellow peel (GYRP), red peel (RP), and red-purple peel (RPP). This integration aimed at elucidating the molecular mechanisms associated with these changes. A total of ten anthocyanins, six carotenoids, and thirty-five xanthophylls were identified throughout the ripening process. The results demonstrated a gradual decrease in the total carotenoid content in the peel with fruit maturation, while anthocyanin content increased significantly. Notably, the accumulation of specific anthocyanins was closely associated with the transition of peel colors from green to red. Integrated metabolomics and transcriptomics analyses identified the GYRP stage as critical for this color transition. A weighted gene co-expression network analysis (WGCNA) revealed that enzyme-coding genes such as 3AT, BZ1, and lcyE, along with transcription factors including MYB, NAC, and bHLH, which interact with PHD and SET TR, may regulate the biosynthesis of anthocyanins and carotenoids, thereby influencing peel pigmentation. These findings provide valuable insights into the molecular mechanisms underlying the accumulation of anthocyanins and carotenoids in Coffea arabica peel during fruit maturation.

Association between Higher Intake of Flavonols and Lignans and Better Mood: Evidence from Dietary and Biomarker Evaluation in Healthy Individuals

SCOPE

The aim of this study is to investigate associations between (poly)phenol consumption, circulating (poly)phenol metabolites, and mood states in healthy individuals.

METHODS AND RESULTS

The study included 333 healthy individuals. Mood state was assessed with the Positive and Negative Affect Schedule questionnaire. Dietary (poly)phenol intake was estimated  matching food consumption data collected using a Food Frequency Questionnaire(FFQ) with a comprehensive in-house (poly)phenol database. A total of 102 (poly)phenol metabolites were quantified in fasting plasma and 24 h urine samples by Liquid Chromatography-Mass Spectrometry using a validated method. A higher intake of lignans, flavanones, and flavonols estimated from FFQs was associated with positive mood after adjusting for age and sex (β: 0.118 to 0.134). A total of 11 urinary (poly)phenol metabolites, including lignan and flavonol metabolites were associated with less negative mood (β: -0.387 to -0.205). No association was found between mood and plasma (poly)phenols.

CONCLUSION

  A higher consumption of lignans flavanones and flavonols is associated with a better mood, while certain urinary metabolites are associated with less negative mood. The lack of associations between fasting plasma (poly)phenols and mood may be due to their transient nature incirculation compared with 24 h urinary metabolites, which reflect longer-term exposure.

Naringin and Naringenin: Potential Multi-Target Agents for Alzheimer's Disease

Alzheimer's disease (AD) is one of the most common forms of neurodegenerative dementia. The etiology of AD is multifactorial, and its complex pathophysiology involves tau and amyloid-β deposition, increased oxidative stress, neuroinflammation, metabolic disorders, and massive neuronal loss. Due to its complex pathology, no effective cure for AD has been found to date. Therefore, there is an unmet clinical need for the development of new drugs against AD. Natural products are known to be good sources of compounds with pharmacological activity and have potential for the development of new therapeutic agents. Naringin, a naturally occurring flavanone glycoside, is predominantly found in citrus fruits and Chinese medicinal herbs. Mounting evidence shows that naringin and its aglycone, naringenin, have direct neuroprotective effects on AD, such as anti-amyloidogenic, antioxidant, anti-acetylcholinesterase, and anti-neuroinflammatory effects, as well as metal chelation. Furthermore, they are known to improve disordered glucose/lipid metabolism, which is a high risk factor for AD. In this review, we summarize the latest data on the impact of naringin and naringenin on the molecular mechanisms involved in AD pathophysiology. Additionally, we provide an overview of the current clinical applications of naringin and naringenin. The novel delivery systems for naringin and naringenin, which can address their widespread pharmacokinetic limitations, are also discussed. The literature indicates that naringin and naringenin could be multilevel, multitargeted, and multifaceted for preventing and treating AD.

Bioengineered Anthocyanin-Enriched Tomatoes: A Novel Approach to Colorectal Cancer Prevention

Colorectal cancer (CRC) remains a significant global health challenge, with barriers to effective prevention and treatment including tumor recurrence, chemoresistance, and limited overall survival rates. Anthocyanins, known for their strong anti-cancer properties, have shown promise in preventing and suppressing various cancers, including CRC. However, natural sources of anthocyanins often fail to provide sufficient quantities needed for therapeutic effects. Bioengineered crops, particularly anthocyanin-enriched tomatoes, offer a viable solution to enhance anthocyanin content. Given its large-scale production and consumption, tomatoes present an ideal target for bioengineering efforts aimed at increasing dietary anthocyanin intake. This review provides an overview of anthocyanins and their health benefits, elucidating the mechanisms by which anthocyanins modulate the transcription factors involved in CRC development. It also examines case studies demonstrating the successful bioengineering of tomatoes to boost anthocyanin levels. Furthermore, the review discusses the effects of anthocyanin extracts from bioengineered tomatoes on CRC prevention, highlighting their role in altering metabolic pathways and reducing tumor-related inflammation. Finally, this review addresses the challenges associated with bioengineering tomatoes and proposes future research directions to optimize anthocyanin enrichment in tomatoes.

Plant Flavonoids with Antimicrobial Activity against Methicillin-Resistant Staphylococcus aureus (MRSA)

Methicillin-resistant Staphylococcus aureus (MRSA) has become a serious threat to human public health and global economic development, and there is an urgent need to develop new antimicrobial agents. Flavonoids are the largest group of plant secondary metabolites, and the anti-S. aureus and anti-MRSA activities of flavonoids have now been widely reported. The aim of this Review is to describe plant-derived flavonoid active ingredients and their effects and mechanisms of inhibitory activity against MRSA in order to provide insights for screening novel antimicrobial agents. Here, 85 plant-derived flavonoids (14 flavones, 21 flavonols, 26 flavanones, 9 isoflavones, 12 chalcones, and 3 other classes) with anti-MRSA activity are reviewed. Among these flavonoids, flavones and isoflavones generally showed the most significant anti-MRSA activity (MICs: 1-8 μg/mL). The results of the present Review display that most of the flavonoids with excellent anti-MRSA activity were derived from Morus alba L. and Paulownia tomentosa (Thunb.) Steud. The antibacterial mechanism of flavonoids against MRSA is mainly achieved by disruption of membrane structures, inhibition of efflux pumps, and inhibition of β-lactamases and bacterial virulence factors. We hope this Review can provide insights into the development of novel antimicrobials based on natural products for treating MRSA infections.

Strawberry (Fragaria x Ananassa) intake on human health and disease outcomes: a comprehensive literature review

Strawberries provide a number of potential health promoting phytonutrients to include phenolics, polyphenols, fiber, micronutrients and vitamins. The objective of this review is to provide a comprehensive summary of recent human studies pertaining to the intake of strawberry and strawberry phytonutrients on human health. A literature search conducted through PubMed and Cochrane databases consolidated studies focusing on the effects of strawberry intake on human health. Articles were reviewed considering pre-determined inclusion and exclusion criteria, including experimental or observational studies that focused on health outcomes, and utilized whole strawberries or freeze-dried strawberry powder (FDSP), published between 2000-2023. Of the 60 articles included in this review, 47 were clinical trials, while 13 were observational studies. A majority of these studies reported on the influence of strawberry intake on cardiometabolic outcomes. Study designs included those examining the influence of strawberry intake during the postprandial period, short-term trials randomized with a control, or a single arm intake period controlling with a low polyphenolic diet or no strawberry intake. A smaller proportion of studies included in this review examined the influence of strawberry intake on additional outcomes of aging including bone and brain health, and cancer risk. Data support that the inclusion of strawberries into the diet can have positive impacts during the postprandial period, with daily intake improving outcomes of lipid metabolism and inflammation in those at increased cardiovascular risk.

Catabolism of phenolics from grape peel and its effects on gut microbiota during in vitro colonic fermentation

BACKGROUND

Grape peels, the main by-products of wine processing, are rich in bioactive ingredients of phenolics, including proanthocyanidins, flavonoids and anthocyanins. Phenolics have the function of regulating intestinal microbiota and promoting intestinal health. From the perspective of the dietary nutrition of grape peel phenolics (GPP), the present study aimed to investigate the influence of GPP on the composition and metabolism of human gut microbiota during in vitro fermentation.

RESULTS

The results indicated that GPP could decrease pH and promote the production of short-chain fatty acids. ACE and Chao1 indices in GPP group were lower than that of the Blank group. GPP enhanced the levels of Lachnospiraceae UCG-004, Bacteroidetes and Roseburia, but reduced the Firmicutes/Bacteroidetes ratio. Kyoto Encyclopedia of Proteins and Genome enrichment pathways related to phenolic acid metabolism mainly included flavonoid, anthocyanin, flavone and flavonol biosynthesis. Gut microbiota could accelerate the release and breakdown of phenolic compounds, resulting in a decrease in the content of hesperetin-7-O-glucoside, delphinidin-3-O-glucoside and cyanidin-3-rutinoside etc. In vitro antibacterial test found that GPP increased the diameters of the inhibition zones of Escherichia coli and Staphylococcus aureus in a dose-dependent manner.

CONCLUSION

The results of the present study revealed that GPP might be a potential prebiotic-like to prevent diseases by improving gut health. The findings could provide a theoretical basis for the potential to exploit GPP as dietary nutrition to maintain intestinal function. © 2024 Society of Chemical Industry.

Polyphenol-Rich Aronia melanocarpa Fruit Beneficially Impact Cholesterol, Glucose, and Serum and Gut Metabolites: A Randomized Clinical Trial

Polyphenol-rich Aronia fruits have great potential as a functional food with anti-inflammatory, hypolipidemic, and hypoglycemic biologic activities. However, clinical intervention trials investigating the impact of Aronia fruit consumption on human health are limited. A randomized, controlled, double-blinded, parallel intervention trial was conducted using 14 human subjects who ingested either 0 mL or 100 mL of Aronia juice daily for 30 days. Anthropometric measurements, fasting, and postprandial measures of glucose and lipid metabolism and inflammation, 16S rRNA fecal microbial composition data, and mass spectrometry-acquired serum and fecal metabolomic data were collected before and after the intervention period. Data were analyzed using general linear models, ANOVA, and t-tests. Daily consumption of Aronia prevented a rise in cholesterol levels (β = -0.50, p = 0.03) and reduced postprandial glucose (β = -3.03, p < 0.01). No difference in microbial community composition by condition was identified at any taxonomic level, but a decrease (β = -18.2, p = 0.04) in microbial richness with Aronia was detected. Serum and fecal metabolomic profiles indicated shifts associated with central carbon and lipid metabolism and decreases in pro-inflammatory metabolites. Our study further informs the development of polyphenol-based dietary strategies to lower metabolic disease risk.

Stabilization effect and interaction mechanism of mannoprotein on anthocyanins in mulberry juice

This study aimed to investigate the problem of color instability in mulberry juice, examine the effect of mannoprotein (MP) dosage on improving the stability of anthocyanins in mulberry juice, and explore the molecular binding mechanism between them. As the mass ratio of anthocyanins to MP of 1.07 × 10-3: 1-1.65 × 10-3: 1, the retention rates of anthocyanins in mulberry juice and simulated system were significantly improved in the photostability experiment, with the highest increase of 128.89 % and 24.11 %, respectively. In the thermal stability experiment, it increased by 7.96 % and 18.49 %, respectively. The synergistic effect of combining MP with anthocyanins has been demonstrated to greatly enhance their antioxidant capacity, as measured by ABTS, FRAP, and potassium ferricyanide reduction method. Furthermore, MP stabilized more anthocyanins to reach the intestine in simulated in vitro digestion. MP and cyanidin-3-glucoside (C3G) interacted with each other through hydrogen bonding and hydrophobic interactions. Specific amino acid residues involved of MP in binding process were identified as threonine (THR), isoleucine (ILE) and arginine (ARG). The identification of the effective mass concentration ratio range and binding sites of MP and anthocyanins provided valuable insights for the application of MP in mulberry juice.

Hesperidin reduces systolic blood pressure in diabetic patients and has no effect on blood pressure in healthy individuals: A systematic review and meta-analysis

In recent years, there have been a number of studies where hesperidin was administered to modify arterial blood pressure, but the conclusions of each study are contradictory. In order to investigate the effect of hesperidin on blood pressure, we searched the CNKI, Wanfang Database, the VIP database, Sinomed database, Pubmed, Embase and The Cochrane Library databases, and searched the literature on hesperidin and blood pressure published in Chinese and English journals, mainly focusing on patients' systolic blood pressure and diastolic blood pressure. The search time frame was from the inception of the databases until December 2023. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess the overall quality and used Cohen's kappa coefficient (κ) to measure agreement. We did preliminary screening of the retrieved literature through Notexpress, 14 articles with a total of 656 patients were included. Cochrance data conversion tool was used for data conversion, and RevMan 5.3 was used for meta-analysis, and finally Stata was used to make the Egger's test for the included study. The results of total population blood pressure showed that hesperidin had no antihypertensive effect on the population, but the conclusions changed when the population was divided into groups. The results of different populations showed that hesperidin had no effect on systolic blood pressure (weighted mean difference [WMD] = -0.50, 95% CI: -3.25 ~ 2.26, Z = 0.35, p = 0.72) and diastolic blood pressure (WMD = -0.51, 95% CI: -2.53 ~ 1.51, Z = 0.50, p = 0.62) in healthy individuals. However, hesperidin reduced systolic blood pressure in patients with type 2 diabetes (WMD = -4.32, 95% CI: - 7.77 ~ - 0.87, Z = 2.45, p = 0.01), and had a tendency to reduce diastolic blood pressure in diabetic patients (WMD = -3.72, 95% CI: -7.63 ~ 0.18, Z = 1.87, p = 0.06). The results in patients with type 2 diabetes needed to be further supported by future research focusing on individuals with diabetes.

Diet-Induced Rodent Obesity Is Prevented and the Fecal Microbiome Is Improved with Elderberry (Sambucus nigra ssp. canadensis) Juice Powder

Anthocyanin-rich edible berries protect against diet-induced obesity in animal models. Prevention is mediated through the bidirectional relationship with the fecal microbiome, and gut-derived phenolic metabolite absorption increases with physical activity, which may influence bioactivity. The objective of this study was to test elderberry juice powder on the development of diet-induced obesity and its influence on the fecal microbiome alone or in combination with physical activity. Male C57BL/6J mice were assigned to one of four treatments, including (1) high-fat diet without wheel access; (2) high-fat diet with unlimited wheel access; (3) high-fat diet supplemented with 10% elderberry juice powder without wheel access; and (4) high-fat diet supplemented with 10% elderberry juice powder with unlimited wheel access. Body weight gain, fat pads, and whole-body fat content in mice fed elderberry juice were significantly less than in mice fed the control diet independent of wheel access. At the end of the study, active mice fed elderberry juice ate significantly more than active mice fed a control diet. There was no difference in the physical activity between active groups. Elderberry juice increasedBifidobacterium, promotedAkkermansia and Anaeroplasma, and prevented the growth of Desulfovibrio. Elderberry juice is a potent inhibitor of diet-induced obesity with action mediated by the gut microbiota.

Chronic consumption of a bergamot-based beverage does not affect glucose, lipid and inflammatory biomarkers of cardiometabolic risk in healthy subjects: a randomised controlled intervention study

Background: Pure bergamot juice exerts lipid lowering effects in dyslipidemic subjects. It is unknown whether bergamot-based beverages exert similar effects in healthy subjects. Aim: To assess the effects, if any, of a bergamot-based beverage (BBB, bergamot juice ≤25%) on lipid, metabolic and inflammatory biomarkers. Methods: Forty-five healthy subjects were randomised 1 : 1 to BBB intake (400 mL day-1) (55.5%) or control (44.5%) for 12 weeks. Anthropometric (waist circumference, body mass index (BMI)) and clinical (blood pressure) parameters, blood samples (glucose, glycated haemoglobin, insulinemia, lipid profile, liver and renal function, inflammatory biomarkers) and 24-h urine for the analysis of (poly)phenol metabolites were collected at the baseline and at 12 weeks. Intakes of energy, nutrients and food groups were assessed by a 7-day dietary record. Results: Both groups exhibited a time-related significant decrease in total cholesterol (p = 0.02), fasting plasma glucose (p = 0.016), insulin (p = 0.034), BMI (p < 0.001) and waist circumference (p = 0.04), but with no significant between-arm difference. The urinary profile of metabolites from the BBB-derived (poly)phenols well discriminated the two study groups, documenting good compliance in the intervention arm. Notably, urinary bergamot 3-hydroxy-3-methylglutaryl (HMG) -containing flavanones or derived HMG-containing metabolites were not detectable. BBB was well tolerated and no adverse events were recorded. Conclusion: This first randomized controlled trial of BBB consumption in healthy subjects showed no effects of BBB on the cardiometabolic risk profile. BBB consumption is a safe nutritional adjunct in the context of a well balanced diet.

Naringenin: its chemistry and roles in neuroprotection

According to epidemiological research, as the population ages, neurological illnesses are becoming a bigger issue. Despite improvements in the treatment of these diseases, there are still widespread worries about how to find a long-lasting remedy. Several neurological diseases can be successfully treated with natural substances. As a result, current research has been concentrated on finding effective neuroprotective drugs with improved efficacy and fewer side effects. Naringenin is one potential treatment for neurodegenerative diseases. Many citrus fruits, tomatoes, bergamots, and other fruits are rich in naringenin, a flavonoid. This phytochemical is linked to a variety of biological functions. Naringenin has attracted a lot of interest for its ability to exhibit neuroprotection through several mechanisms. In the current article, we present evidence from the literature that naringenin reduces neurotoxicity and oxidative stress in brain tissues. Also, the literatures that are currently accessible shows that naringenin reduces neuroinflammation and other neurological anomalies. Additionally, we found several studies that touted naringenin as a promising anti-amyloidogenic, antidepressant, and neurotrophic treatment option. This review's major goal is to reflect on advancements in knowledge of the molecular processes that underlie naringenin's possible neuroprotective effects. Furthermore, this article also provides highlights of Naringenin with respect to its chemistry and pharmacokinetics.

Petanin Potentiated JNK Phosphorylation to Negatively Regulate the ERK/CREB/MITF Signaling Pathway for Anti-Melanogenesis in Zebrafish

Petanin, an acylated anthocyanin from the Solanaceae family, shows potential in tyrosinase inhibitory activity and anti-melanogenic effects; however, its mechanism remains unclear. Therefore, to investigate the underlying mechanism of petanin's anti-melanogenic effects, the enzyme activity, protein expression and mRNA transcription of melanogenic and related signaling pathways in zebrafish using network pharmacology, molecular docking and molecular dynamics simulation were combined for analysis. The results showed that petanin could inhibit tyrosinase activity and melanogenesis, change the distribution and arrangement of melanocytes and the structure of melanosomes, reduce the activities of catalase (CAT) and peroxidase (POD) and enhance the activity of glutathione reductase (GR). It also up-regulated JNK phosphorylation, inhibited ERK/RSK phosphorylation and down-regulated CREB/MITF-related protein expression and mRNA transcription. These results were consistent with the predictions provided through network pharmacology and molecular docking. Thus, petanin could inhibit the activity of tyrosinase and the expression of tyrosinase by inhibiting and negatively regulating the tyrosinase-related signaling pathway ERK/CREB/MITF through p-JNK. In conclusion, petanin is a good tyrosinase inhibitor and anti-melanin natural compound with significant market prospects in melanogenesis-related diseases and skin whitening cosmetics.

In Vivo Behavior of Hydrolyzable Tannins after Oral Administration of the Trapa bispinosa Extract to Rats

The pericarp extract of Trapa bispinosa (TBPE), which is rich in hydrolyzable tannins, has been reported to inhibit α-glucosidase and glycation reactions. We investigated the in vivo behavior of hydrolyzable tannins and related metabolites after administration of TBPE to rats. Using high pressure liquid chromatography-electrospray ionization-tandem mass spectroscopy (HPLC-ESI-MS/MS), 12 ellagitannin metabolites, such as urolithins and 6 gallotannin metabolites, produced in the collected plasma and urine were quantified. Urolithins and gallic acid metabolites reached their maximum blood concentration after 24 and 1 h of administration, respectively. Conversely, the excretion of urolithins in urine required up to 72 h and followed a sigmoidal curve, whereas gallic acid metabolites were rapidly excreted earlier after administration. The results suggest that the metabolites gallotannin and ellagitannin are responsible for the antiglycation effect of TBPE, which proceeds via different mechanisms and times. Our findings provide basic data demonstrating the functionality of hydrolyzable tannins as well as Trapa ingredients.

Grape/Blueberry Anthocyanins and Their Gut-Derived Metabolites Attenuate LPS/Nigericin-Induced Inflammasome Activation by Inhibiting ASC Speck Formation in THP-1 Monocytes

Inflammasomes are multi-protein complexes, which are formed in response to tissue injury, infections, and metabolic stress. However, aberrant inflammasome activation has been linked to several inflammatory diseases. Anthocyanins have been reported to attenuate NLR family pyrin domain-containing 3 (NLRP3) inflammasome activation, but the influence of grape/blueberry anthocyanins and especially their gut-derived metabolites on NLRP3 inflammasome activation in human monocytes remains unclear. Therefore, human leukemic monocytes (THP-1 cells, Tohoku Hospital Pediatrics-1 cells) were preincubated with different concentrations of grape/blueberry anthocyanins, homovanillyl alcohol, or 2,4,6-trihydroxybenzaldehyde (THBA) before the NLRP3 inflammasome was activated by lipopolysaccharide and/or nigericin. Apoptosis-associated speck-like protein containing a CARD (ASC) speck formation, as well as ASC and NLRP3 protein expression, were determined using flow cytometry. Caspase-1 activity was measured in cultured cells, and pro-inflammatory cytokine secretion was determined using enzyme-linked immunosorbent assays. Anthocyanins and their metabolites had no effect on ASC or NLRP3 protein expression. However, THBA significantly inhibited ASC speck formation in primed and unprimed THP-1 monocytes, while caspase-1 activity was significantly declined by grape/blueberry anthocyanins. Furthermore, reduced inflammasome activation resulted in lower pro-inflammatory cytokine secretion. In conclusion, our results show for the first time that grape/blueberry anthocyanins and their gut-derived metabolites exert anti-inflammatory effects by attenuating NLRP3 inflammasome activation in THP-1 monocytes.

Research progress on the regulation of oxidative stress by phenolics: the role of gut microbiota and Nrf2 signaling pathway

In recent years, the increase in high-calorie diets and sedentary lifestyles has made obesity a global public health problem. An unbalanced diet promotes the production of proinflammatory cytokines and causes redox imbalance in the body. Phenolics have potent antioxidant activity and cytoprotective ability. They can scavenge free radicals and reactive oxygen species, and enhance the activity of antioxidant enzymes, thus combating the body's oxidative stress. They can also improve the body's inflammatory response, enhance the enzyme activity of lipid metabolism, and reduce the contents of cholesterol and triglyceride. Most phenolics are biotransformed and absorbed into the blood after the action by gut microbiota; these metabolites then undergo phase I and II metabolism and regulate oxidative stress by scavenging free radicals and increasing expression of antioxidant enzymes. Phenolics induce the expression of genes encoding antioxidant enzymes and phase II detoxification enzymes by stimulating Nrf2 to enter the nucleus and bind to the antioxidant response element after uncoupling from Keap1, thereby promoting the production of antioxidant enzymes and phase II detoxification enzymes. The absorption rate of phenolics in the small intestine is extremely low. Most phenolics reach the colon, where they interact with the microbiota and undergo a series of metabolism. Their metabolites will reach the liver via the portal vein and undergo conjugation reactions. Subsequently, the metabolites reach the whole body to exert biological activity by traveling with the systemic circulation. Phenolics can promote the growth of probiotics, reduce the ratio of Firmicutes/Bacteroidetes (F/B), and improve intestinal microecological imbalance. This paper reviews the nutritional value, bioactivity, and antioxidant mechanism of phenolics in the body, aiming to provide a scientific basis for the development and utilization of natural antioxidants and provide a reference for elucidating the mechanism of action of phenolics for regulating oxidative stress in the body. © 2023 Society of Chemical Industry.

Industrial and culinary treatments applied to Piquillo pepper (Capsicum annuum cv. Piquillo) impact positively on (poly)phenols' bioaccessibility and gut microbiota catabolism

Thermal treatments applied to plant-based foods prior to consumption might influence (poly)phenols' bioaccessibility and the metabolization of these compounds by the gut microbiota. In the present research, the impact of industrial (grilling and canning) and culinary (microwaving and frying) treatments on the bioaccessibility and colonic biotransformations of (poly)phenols from Piquillo pepper (Capsicum annum cv. Piquillo) were evaluated by in vitro gastrointestinal digestion and colonic fermentation models and HPLC-ESI-MS/MS. The application of industrial treatments impacted positively on (poly)phenols' bioaccessibility compared to raw pepper. Microwaving also exerted a positive effect on (poly)phenols' bioaccessibility compared to canning whereas the addition of oil for frying seemed to negatively affect (poly)phenols' release from the food matrix. Throughout the 48 hours of the colonic fermentation process (poly)phenolic compounds were catabolized into different (poly)phenol derivatives whose formation was also positively affected by industrial and culinary treatments. Based on the concentration and time of appearance of these derivatives, catabolic pathways of (poly)phenols from Piquillo pepper were proposed. The major (poly)phenol derivatives identified (3-(3'-hydroxyphenyl)propanoic acid, 4-hydroxy-3-methoxyphenylacetic acid and benzene-1,2-diol) are considered of great interest for the study of their bioactivity and the potential effect on human health.

Aromatic Amine and Chiral Phosphoric Acid Synergistic Catalyzed Cascade Reaction of Alkynylnaphthols with Aldehydes

A novel approach using aromatic amines and chiral phosphoric acids in a synergistic catalytic cascade reaction of 2-alkynylnaphthols with aldehydes has been established. This method offers a direct route to preparing flavanone analogues with excellent stereoselectivity. Mechanistic studies reveal a sequential process involving addition, elimination, cyclization, and hydrolysis in which aromatic amines and chiral phosphoric acids play key roles via imine-enamine and hydrogen bonding models.

The role of environmental stress in fruit pigmentation

For many fruit crops, the colour of the fruit outwardly defines its eating quality. Fruit pigments provide reproductive advantage for the plant as well as providing protection against unfavourable environmental conditions and pathogens. For consumers these colours are considered attractive and provide many of the dietary benefits derived from fruits. In the majority of species, the main pigments are either carotenoids and/or anthocyanins. They are produced in the fruit as part of the ripening process, orchestrated by phytohormones and an ensuing transcriptional cascade, culminating in pigment biosynthesis. Whilst this is a controlled developmental process, the production of pigments is also attuned to environmental conditions such as light quantity and quality, availability of water and ambient temperature. If these factors intensify to stress levels, fruit tissues respond by increasing (or ceasing) pigment production. In many cases, if the stress is not severe, this can have a positive outcome for fruit quality. Here, we focus on the principal environmental factors (light, temperature and water) that can influence fruit colour.

Nutrikinetics and urinary excretion of phenolic compounds after a 16-week supplementation with a flavanone-rich ingredient

Background: Polyphenols are a broad group of compounds with a complex metabolic fate. Flavanones and their metabolites provide cardiovascular protection and assistance in long-term body composition management. Objective: This study evaluates the nutrikinetics and the bioavailability of phenolic compounds after both acute and chronic supplementation with a flavanone-rich product, namely Sinetrol® Xpur, in healthy overweight and obese volunteers. Design: An open-label study including 20 volunteers was conducted for 16 weeks. Participants received Sinetrol® Xpur, either a low dose (900 mg per day) or a high dose (1800 mg per day), in capsules during breakfast and lunch. They were advised to follow an individualized isocaloric diet and avoid a list of polyphenol-rich foods 48 hours before and during the pharmacokinetic measurements. Results: Over 20 phase II and colonic metabolites were measured in the plasma. Two peaks were observed at 1 h and 7h-10 h after the first capsule ingestion. No significant differences in the AUC were observed in circulating metabolites between both doses. In urine excretion, 53 metabolites were monitored, including human phase II and colonic metabolites, at weeks 1 and 16. Cumulative urine excretion was higher after the high dose than after the low dose in both acute and chronic studies. Total urinary metabolites were significantly lower in week 16 compared to week 1. Conclusion: Although the urinary excreted metabolites reduced significantly over 16 weeks, the circulating metabolites did not decrease significantly. This study suggests that chronic intake might not offer the same bioavailability as in the acute study, and this effect does not seem to be dose-dependent. The clinical trial registry number is NCT03823196.

Hesperetin-7-O-glucoside/β-cyclodextrin Inclusion Complex Induces Acute Vasodilator Effect to Inhibit the Cold Sensation Response during Localized Cold-Stimulate Stress in Healthy Human Subjects: A Randomized, Double-Blind, Crossover, and Placebo-Controlled Study

Hesperetin, a citrus flavonoid, exerts vasodilation and is expected to improve endothelial function and alleviate cold sensation by activating nervous system thermal transduction pathways. In this randomized, double-blind, crossover, and placebo-controlled study, the purpose was to assess the effect of an orally administered highly bioavailable soluble inclusion complex of hesperetine-7-O-glucoside with β-cyclodextrin (HEPT7G/βCD; SunActive® HES/HCD) on cold sensation response during localized cold-stimulated stress in healthy humans. A significant (p ≤ 0.05) dose-dependent increase in skin cutaneous blood flow following relatively small doses of HEPT7G/βCD inclusion complex ingestion was confirmed, which led to a relatively effective recovery of peripheral skin temperature. The time delay of an increase in blood flow during rewarming varied significantly between low- and high-dose HEPT7G/βCD inclusion complex consumption (e.g., 150 mg and 300 mg contain 19.5 mg and 39 mg of HEPT7G, respectively). In conclusion, the substantial alteration in peripheral skin blood flow observed during local cooling stress compared to placebo suggested that deconjugated hesperetin metabolites may have a distinct capacity for thermoregulatory control of human skin blood flow to maintain a constant body temperature during cold stress exposure via cutaneous vasodilation and vasoconstriction systems.

Health benefits of anthocyanin-containing foods, beverages, and supplements have unpredictable relation to gastrointestinal microbiota: A systematic review and meta-analysis of random clinical trials

Anthocyanins are a type of natural pigment that has numerous health benefits. In recent years, the interaction of anthocyanins with gastrointestinal (GI) microbiota has been presented as a viable paradigm for explaining anthocyanin activities. The current study performed a systematic review and meta-analysis to determine the potential modulation of GI microbiota by anthocyanins in human health improvement. Clinical trials were retrieved from PubMed, Cochrane, Web of Knowledge, China Biology Medicine, China National Knowledge Infrastructure, and ClinicalTrials.gov with no language restrictions. Eight clinical trials (252 participants) were selected from the 1121 identified studies and the relative phylum abundance extracted from the trials was analyzed using a random-effects model. Based on the analysis, anthocyanins had no effect on the relative abundance of Firmicutes (standard mean difference [SMD]: -0.46 [-1.25 to 0.34], P = .26), Proteobacteria (SMD, -0.32 [-0.73 to 0.09], P = .13), nor Actinobacteria (SMD, -0.19 [-0.50 to 0.12], P = 0.24), but influenced the abundance of Bacteroidetes (SMD, 0.84 [0.17 to 1.52], P = .01) when compared with placebo/control. No significant influence on the relative abundance was detected when the data were analyzed following the "posttreatment vs. pretreatment" strategy. Our preliminary analysis revealed that the effects of anthocyanins on human GI microbiota vary between studies and individuals, and at the current stage, the clinical trials regarding the effects of anthocyanin interventions on human GI microbiota are lacking. More trials with larger sample sizes are needed to promote the clinical application of anthocyanins.

Antioxidant Activity, Metabolism, and Bioavailability of Polyphenols in the Diet of Animals

As the world’s population grows, so does the need for more and more animal feed. In 2006, the EU banned the use of antibiotics and other chemicals in order to reduce chemical residues in food consumed by humans. It is well known that oxidative stress and inflammatory processes must be combated to achieve higher productivity. The adverse effects of the use of pharmaceuticals and other synthetic compounds on animal health and product quality and safety have increased interest in phytocompounds. With the use of plant polyphenols in animal nutrition, they are gaining more attention as a supplement to animal feed. Livestock feeding based on a sustainable, environmentally friendly approach (clean, safe, and green agriculture) would also be a win–win for farmers and society. There is an increasing interest in producing healthier products of animal origin with a higher ratio of polyunsaturated fatty acids (PUFAs) to saturated fatty acids by modulating animal nutrition. Secondary plant metabolites (polyphenols) are essential chemical compounds for plant physiology as they are involved in various functions such as growth, pigmentation, and resistance to pathogenic organisms. Polyphenols are exogenous antioxidants that act as one of the first lines of cell defense. Therefore, the discoveries on the intracellular antioxidant activity of polyphenols as a plant supplement have contributed significantly to the improvement of antioxidant activity, as polyphenols prevent oxidative stress damage and eliminate excessively produced free radicals. To achieve animal welfare, reduce stress and the need for medicines, and increase the quality of food of animal origin, the addition of polyphenols to research and breeding can be practised in part with a free-choice approach to animal nutrition.

Accounting Gut Microbiota as the Mediator of Beneficial Effects of Dietary (Poly)phenols on Skeletal Muscle in Aging

Sarcopenia, the age-related loss of muscle mass and function increasing the risk of disability and adverse outcomes in older people, is substantially influenced by dietary habits. Several studies from animal models of aging and muscle wasting indicate that the intake of specific polyphenol compounds can be associated with myoprotective effects, and improvements in muscle strength and performance. Such findings have also been confirmed in a smaller number of human studies. However, in the gut lumen, dietary polyphenols undergo extensive biotransformation by gut microbiota into a wide range of bioactive compounds, which substantially contribute to bioactivity on skeletal muscle. Thus, the beneficial effects of polyphenols may consistently vary across individuals, depending on the composition and metabolic functionality of gut bacterial communities. The understanding of such variability has recently been improved. For example, resveratrol and urolithin interaction with the microbiota can produce different biological effects according to the microbiota metabotype. In older individuals, the gut microbiota is frequently characterized by dysbiosis, overrepresentation of opportunistic pathogens, and increased inter-individual variability, which may contribute to increasing the variability of biological actions of phenolic compounds at the skeletal muscle level. These interactions should be taken into great consideration for designing effective nutritional strategies to counteract sarcopenia.

Differences Due to Sex and Sweetener on the Bioavailability of (Poly)phenols in Urine Samples: A Machine Learning Approach

Metabolic diseases have been related to the overdrinking of high-sugar content beverages. As a result, the demand for alternative formulations based on plant-based ingredients with health-promoting properties has increased during the last few years. Nonetheless, the design and production of effective formulations requires understanding the bioavailability of these compounds. For this purpose, a two-month longitudinal trial with 140 volunteers was conducted to measure the beneficial effects of a maqui-citrus beverage, rich in (poly)phenols. From data obtained by quantifying metabolites present in urine samples, biostatistical and machine learning (data imputation, feature selection, and clustering) methods were applied to assess whether a volunteer's sex and the sweetener added to the beverage (sucrose, sucralose, or stevia) affected the bioavailability of (poly)phenol metabolites. Several metabolites have been described as being differentially influenced: 3,4-dihydroxyphenylacetic acid and naringenin with its derivatives were positively influenced by stevia and men, while eriodictyol sulfate and homoeridictyol glucunoride concentrations were enhanced with stevia and women. By examining groups of volunteers created by clustering analysis, patterns in metabolites' bioavailability distribution as a function of sex and/or sweeteners (or even due to an uncontrolled factor) were also discovered. These results underline the potential of stevia as a (poly)phenol bioavailability enhancer. Furthermore, they also evidence sex affects the bioavailability of (poly)phenols, pointing at a sex-dependent metabolic pathway regulation.

Biological valorization of lignin to flavonoids

Lignin is the most affluent natural aromatic biopolymer on the earth, which is the promising renewable source for valuable products to promote the sustainability of biorefinery. Flavonoids are a class of plant polyphenolic secondary metabolites containing the benzene ring structure with various biological activities, which are largely applied in health food, pharmaceutical, and medical fields. Due to the aromatic similarity, microbial conversion of lignin derived aromatics to flavonoids could facilitate flavonoid biosynthesis and promote the lignin valorization. This review thereby prospects a novel valorization route of lignin to high-value natural products and demonstrates the potential advantages of microbial bioconversion of lignin to flavonoids. The biodegradation of lignin polymers is summarized to identify aromatic monomers as momentous precursors for flavonoid synthesis. The biosynthesis pathways of flavonoids in both plants and strains are introduced and compared. After that, the key branch points and important intermediates are clearly discussed in the biosynthesis pathways of flavonoids. Moreover, the most significant enzyme reactions including Claisen condensation, cyclization and hydroxylation are demonstrated in the biosynthesis pathways of flavonoids. Finally, current challenges and potential future strategies are also discussed for transforming lignin into various flavonoids. The holistic microbial conversion routes of lignin to flavonoids could make a sustainable production of flavonoids and improve the feasibility of lignin valorization.

One-Week Elderberry Juice Treatment Increases Carbohydrate Oxidation after a Meal Tolerance Test and Is Well Tolerated in Adults: A Randomized Controlled Pilot Study

Obesity in the United States continues to worsen. Anthocyanin-rich fruits and vegetables provide a pragmatic dietary approach to slow its metabolic complications. Given American diet patterns, foods with high anthocyanin content could address dose-response challenges. The study objective was to determine the effect of 100% elderberry juice on measures of indirect calorimetry (IC) and insulin sensitivity/glucose tolerance in a placebo-controlled, randomized, crossover pilot study. Overweight and obese adults were randomized to a 5-week study which included 2 1-week periods of twice-daily elderberry juice (EBJ) or sugar-matched placebo consumption separated by a 3-week washout period. Following each 1-week test period, IC and insulin sensitivity/glucose tolerance was measured with a 3 h meal tolerance test (MTT). Treatment differences were tested with linear mixed modeling. A total of 22 prospective study volunteers (18 F/4 M) attended recruitment meetings, and 9 were analyzed for treatment differences. EBJ was well tolerated and compliance was 99.6%. A total of 6 IC measures (intervals) were created, which coincided with 10-20 min gaseous samplings in-between MTT blood samplings. Average CHO oxidation was significantly higher during the MTT after 1-week EBJ consumption (3.38 vs. 2.88 g per interval, EBJ vs. placebo, p = 0.0113). Conversely, average fat oxidation was significantly higher during the MTT after 1-week placebo consumption (1.17 vs. 1.47 g per interval, EBJ vs. placebo, p = 0.0189). This was in-line with a significantly lower average respiratory quotient after placebo treatment (0.87 vs. 0.84, EBJ vs. placebo, p = 0.0114). Energy expenditure was not different. There was no difference in serum glucose or insulin response between treatments. This pilot study of free-living volunteers describes significant change in IC but not insulin sensitivity with an EBJ intervention. Controlled feeding and increased sample size will help determine the utility of EBJ on these outcomes.

Bioavailability of orange juice (poly)phenols: β-glucan-rich oat bran decreases urinary excretion of flavanone phase II metabolites and enhances excretion of microbiota-derived phenolic catabolites

The impact of β-glucan-rich oat bran on the bioavailability of orange juice (OJ) flavanones was investigated. Volunteers consumed 500 mL of OJ with and without 22 g of oat bran containing 6 g of β-glucan (OB-6). Urine collected 12 h prior to and over a 0-24 h period post-supplementation was analysed by UHPLC-HRMS. Sixteen flavanone metabolites and thirty-nine colon-derived phenolic catabolites were identified and quantified. The major compounds were hesperetin-3'-glucuronide, along with hippuric acids and the C₆-C₃ phenolic acids 3-(3'-hydroxy-4'-methoxyphenyl)hydracrylic acid and 3-(4'-hydroxy-3'-methoxyphenyl)propanoic acid. A marked reduction in the 0-24 h excretion of flavanone metabolites from 29.7 μmol (9.3% recovery) to 9.3 μmol (2.9% recovery), occurred following consumption of OB-6 compared to OJ. This appeared not to be an effect of fiber on the rate of transport in the upper gut. After consumption of OJ there was a 163 ± 15 μmol excretion of colon-derived phenolic catabolites, equivalent to 43% of (poly)phenol intake and following OB-6 intake there was a further significant 30% increase. The β-oat bran in OB-6 contained 5.8 μmol of free and 52 μmol of bound phenolic derivatives compared to 371 μmol of OJ (poly)phenols. The elevated excretion of phenolics after OB-6 consumption appears not to be due to bound phenolics in the bran, rather it is consequence, principally, of a bran-mediated increase in the quantities of flavanones passing from the upper to the lower bowel where they were subjected to microbiota-mediated catabolism. CLINICAL TRIAL REGISTRATION NUMBER: This trial was registered at clinicaltrials.gov as NCT04867655.

Anthocyanin actions at the gastrointestinal tract: Relevance to their health benefits

Anthocyanins (AC) are flavonoids abundant in the human diet, which consumption has been associated to several health benefits, including the mitigation of cardiovascular disease, type 2 diabetes, non-alcoholic fatty liver disease, and neurological disorders. It is widely recognized that the gastrointestinal (GI) tract is not only central for food digestion but actively participates in the regulation of whole body physiology. Given that AC, and their metabolites reach high concentrations in the intestinal lumen after food consumption, their biological actions at the GI tract can in part explain their proposed local and systemic health benefits. In terms of mechanisms of action, AC have been found to: i) inhibit GI luminal enzymes that participate in the absorption of lipids and carbohydrates; ii) preserve intestinal barrier integrity and prevent endotoxemia, inflammation and oxidative stress; iii) sustain goblet cell number, immunological functions, and mucus production; iv) promote a healthy microbiota; v) be metabolized by the microbiota to AC metabolites which will be absorbed and have systemic effects; and vi) modulate the metabolism of GI-generated hormones. This review will summarize and discuss the latest information on AC actions at the GI tract and their relationship to overall health benefits.

Metabolism of eriocitrin in the gut and its regulation on gut microbiota in mice

Introduction

Eriocitrin, found in lemon fruit, has shown a wide range of biological properties. Herein, we investigated the intestinal metabolic profile of eriocitrin in colon, and the regulation of dietary intervention of eriocitrin on gut microbiota.

Methods

We performed ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS), 16S rDNA gene sequencing and gas chromatography-mass (GC-MS) on colon contents from the eriocitrin group (n=6), and compared them with control participants (n=6).

Results

A total of 136 flavonoids were found in colon contents, including eriocitrin and its six metabolites (eriodictyol, homoeriodictyol, hesperetin, eriodictyol-3'-O-glucoside, hesperetin-7-O-glucoside and eriodictyol-7-O-(6″-O-galloyl) glucoside). Moreover, dietary intervention of eriocitrin significantly alters the beta diversity of the gut microbiota, the probiotics such as Lachnospiraceae_UCG_006 were significantly enriched, and the production of butyrate, valerate and hexanoate in the colon pool of short-chain fatty acids were significant increased. The spearman's association analysis performed some intestinal bacteria may be involved in the metabolism of eriocitrin.

Discussion

Collectively, our results preliminarily suggest the metabolism of eriocitrin in the gut, demonstrating alterations of eriocitrin in gut microbiota, which warrants further investigation to determine its potential use in food and biomedical applications.

A Comprehensive Review on Anti-Inflammatory Response of Flavonoids in Experimentally-Induced Epileptic Seizures

Flavonoids, a group of natural compounds with phenolic structure, are becoming popular as alternative medicines obtained from plants. These compounds are reported to have various pharmacological properties, including attenuation of inflammatory responses in multiple health issues. Epilepsy is a disorder of the central nervous system implicated with the activation of the inflammatory cascade in the brain. The aim of the present study was to summarize the role of various neuroinflammatory mediators in the onset and progression of epilepsy, and, thereafter, to discuss the flavonoids and their classes, including their biological properties. Further, we highlighted the modulation of anti-inflammatory responses achieved by these substances in different forms of epilepsy, as evident from preclinical studies executed on multiple epilepsy models. Overall, the review summarizes the available evidence of the anti-inflammatory potential of various flavonoids in epilepsy.

Can exosomes transfer the preconditioning effects triggered by (poly)phenol compounds between cells?

Effective strategies in prolonging life- and health span are increasingly recognized as acting as mild stressors. Micronutrients and other dietary compounds such as (poly)phenols may act as moderate stressors and confer protective effects via a preconditioning phenomenon. (Poly)phenols and their metabolites may not need to reach their target cells to produce biologically significant responses, so that cells exposed to it at entry points may communicate signals to other cells. One of such "communication" mechanisms could occur through extracellular vesicles, including exosomes. In vitro loading of exosomes with (poly)phenols has been used to achieve targeted exosome homing. However, it is unknown if similar shuttling phenomena occur in vivo upon (poly)phenols consumption. Alternatively, exposure to (poly)phenols might trigger responses in exposed organs, which can subsequently signal to cells distant from exposure sites via exosomes. The currently available studies favor indirect effects of (poly)phenols, tempting to suggest a "billiard-like" or "domino-like" propagating effect mediated by quantitative and qualitative changes in exosomes triggered by (poly)phenols. In this review, we discuss the limited current data available on how (poly)phenols exposure can potentially modify exosomes activity, highlighting major questions regarding how (epi)genetic, physiological, and gut microbiota factors can modulate and be modulated by the putative exosome-(poly)phenolic compound interplay that still remains to be fully understood.

Biochemistry of Antioxidants: Mechanisms and Pharmaceutical Applications

Natural antioxidants from fruits and vegetables, meats, eggs and fish protect cells from the damage caused by free radicals. They are widely used to reduce food loss and waste, minimizing lipid oxidation, as well as for their effects on health through pharmaceutical preparations. In fact, the use of natural antioxidants is among the main efforts made to relieve the pressure on natural resources and to move towards more sustainable food and pharmaceutical systems. Alternative food waste management approaches include the valorization of by-products as a source of phenolic compounds for functional food formulations. In this review, we will deal with the chemistry of antioxidants, including their molecular structures and reaction mechanisms. The biochemical aspects will also be reviewed, including the effects of acidity and temperature on their partitioning in binary and multiphasic systems. The poor bioavailability of antioxidants remains a huge constraint for clinical applications, and we will briefly describe some delivery systems that provide for enhanced pharmacological action of antioxidants via drug targeting and increased bioavailability. The pharmacological activity of antioxidants can be improved by designing nanotechnology-based formulations, and recent nanoformulations include nanoparticles, polymeric micelles, liposomes/proliposomes, phytosomes and solid lipid nanoparticles, all showing promising outcomes in improving the efficiency and bioavailability of antioxidants. Finally, an overview of the pharmacological effects, therapeutic properties and future choice of antioxidants will be incorporated.

Phenolic composition of grape pomace and its metabolism

Grape pomace is the most important residual after wine making, and it is considered to be a very abundant source for the extraction of a wide range of polyphenols. These polyphenols exhibit a variety of bioactivities, such as antioxidant, anti-inflammatory, and anti-cancer. They are also beneficial in alleviating metabolic syndrome and regulating intestinal flora, etc. These health effects are most likely contributed by polyphenol metabolite, which are formed by the grape pomace phenolics after a complex metabolic process in vivo. Therefore, understanding the phenolic composition of grape pomace and its metabolism is the basis for an in-depth study of the biological activity of grape pomace polyphenols. In this paper, we first summarize the composition of phenolics in grape pomace, then review the recent studies on the metabolism of grape pomace phenolics, including changes in phenolics in the gastrointestinal tract, their pharmacokinetics in the systemic circulation, the tissue distribution of phenolic metabolites, and the beneficial effects of metabolites on intestinal health, and finally summarize the effects of human health status and dietary fiber on the metabolism of grape polyphenols. It is expected to provide help for the in-depth research on the metabolism and biological activity of grape pomace polyphenol extracts, and to provide theoretical support for the development and utilization of grape pomace.

Characterization of the (Poly)Phenolic Fraction of Fig Peel: Comparison among Twelve Cultivars Harvested in Tuscany

(1) Background: The fig tree (Ficus carica L.) is widely cultivated in the Mediterranean area and it produces fruits largely consumed in the Mediterranean diet. Previous studies have shown that this fruit represents a rich source of (poly)phenols, which are mainly located in the peel rather than the pulp. In our study, fig peel derived from twelve different cultivars located in Tuscany was assessed for its (poly)phenol profile. (2) Methods: The (poly)phenol characterization was performed through ultra-high performance liquid chromatography coupled to multiple-stage mass spectrometry. (3) Results: Twenty-eight (poly)phenolic compounds were quantified in the investigated fig peel. It was possible to observe an interesting variability in the (poly)phenol content among the twelve cultivars of fig peel. Rutin and 5-caffeoylquinic acid were the main compounds in the greenish fig peel, while cyanidin-3-O-rutinoside was the main component in the dark-violet fig peel. (4) Conclusions: fig peel could be used as a (poly)phenol-rich ingredient in several food products to increase the bioactive compound content of foods. Moreover, dark-violet peel could be considered potentially suitable as a natural food colorant.

Flavonoid Intake in Relation to Colorectal Cancer Risk and Blood Bacterial DNA

Flavonoids have been inversely associated to colorectal cancer (CRC) and are plausible intermediaries for the relation among gut microbiome, intestinal permeability and CRC. We analyzed the relation of flavonoid intake with CRC and blood bacterial DNA. We conducted a case-control study in Italy involving 100 incident CRC cases and 200 controls. A valid and reproducible food-frequency questionnaire was used to assess dietary habits and to estimate six flavonoid subclass intakes. We applied qPCR and 16S rRNA gene profiling to assess blood bacterial DNA. We used multiple logistic regression to derive odds ratios (ORs) of CRC and Mann-Whitney and chi--square tests to evaluate abundance and prevalence of operational taxonomic units (OTUs) according to flavonoid intakes. Inverse associations with CRC were found for anthocyanidins (OR for the highest versus the lowest tertile = 0.24, 95% confidence interval, CI = 0.11-0.52) and flavanones (OR = 0.18, 95% CI = 0.08-0.42). We found different abundance and prevalence according to anthocyanidin and flavanone intake for OTUs referring to Oligoflexales order, Diplorickettsiaceae family, Staphylococcus, Brevundimonas, Pelomonas and Escherischia-Shigella genera, and Flavobacterium and Legionella species. The study provides evidence to a protective effect of dietary anthocyanidins and flavanones on CRC and suggests an influence of flavonoids on blood bacterial DNA, possibly through intestinal permeability changes.

BRD9 Inhibition by Natural Polyphenols Targets DNA Damage/Repair and Apoptosis in Human Colon Cancer Cells

Epigenetic mechanisms play an important role in the etiology of colorectal cancer (CRC) and other malignancies due, in part, to deregulated bromodomain (BRD) functions. Inhibitors of the bromodomain and extraterminal (BET) family have entered into clinical trials as anticancer agents, and interest has grown in other acetyl 'reader' proteins as therapeutic targets, including non-BET member bromodomain-containing protein 9 (BRD9). We report here that overexpression of BRD9 is associated with poor prognosis in CRC patients, and that siRNA-mediated knockdown of BRD9 decreased cell viability and activated apoptosis in human colon cancer cells, coincident with increased DNA damage. Seeking natural compounds as BRD9 antagonists, molecular docking in silico identified several polyphenols such as Epigallocatechin-3-gallate (EGCG), Equol, Quercetin, and Aspalathin, with favorable binding energies, supported by BROMOscan^® (DiscoverX) and isothermal titration calorimetry experiments. Polyphenols mimicked BRD9 knockdown and iBRD9 treatment in reducing colon cancer cell viability, inhibiting colony formation, and enhancing DNA damage and apoptosis. Normal colonic epithelial cells were unaffected, signifying cancer-specific effects. These findings suggest that natural polyphenols recognize and target BRD9 for inhibition, and might serve as useful lead compounds for bromodomain therapeutics in the clinical setting.

Potential roles of gut microbes in biotransformation of natural products: An overview

Natural products have been extensively applied in clinical practice, characterized by multi-component and multi-target, many pharmacodynamic substances, complex action mechanisms, and various physiological activities. For the oral administration of natural products, the gut microbiota and clinical efficacy are closely related, but this relationship remains unclear. Gut microbes play an important role in the transformation and utilization of natural products caused by the diversity of enzyme systems. Effective components such as flavonoids, alkaloids, lignans, and phenols cannot be metabolized directly through human digestive enzymes but can be transformed by enzymes produced by gut microorganisms and then utilized. Therefore, the focus is paid to the metabolism of natural products through the gut microbiota. In the present study, we systematically reviewed the studies about gut microbiota and their effect on the biotransformation of various components of natural products and highlighted the involved common bacteria, reaction types, pharmacological actions, and research methods. This study aims to provide theoretical support for the clinical application in the prevention and treatment of diseases and provide new ideas for studying natural products based on gut biotransformation.

A biochemical perspective on the fate of virgin olive oil phenolic compounds in vivo

The chemistry of the phenolic compounds found in virgin olive oil (VOO) is very complex due, not only to the different classes of polyphenols that can be found in it, but, above all, due to the existence of a very specific phenol class found only in oleaceae plants: the secoiridoids. Searching in the Scopus data base the keywords flavonoid, phenolic acid, lignin and secoiridoid, we can find a number of 148174, 79435, 11326 and 1392 research articles respectively, showing how little is devote to the latter class of compounds. Moreover, in contrast with other classes, that include only phenolic compounds, secoiridoids may include phenolic and non-phenolic compounds, being the articles concerning phenolic secoiridoids much less than the half of the abovementioned articles. Therefore, it is important to clarify the structures of these compounds and their chemistry, as this knowledge will help understand their bioactivity and metabolism studies, usually performed by researchers with a more health science's related background. In this review, all the structures found in many research articles concerning VOO phenolic compounds chemistry and metabolism was gathered, with a special attention devoted to the secoiridoids, the main phenolic compound class found in olives, VOO and olive leaf.

Lunularin Producers versus Non-producers: Novel Human Metabotypes Associated with the Metabolism of Resveratrol by the Gut Microbiota

We describe here for the first time the consistent observation of two metabotypes associated with resveratrol metabolism by the human gut microbiota, that is, lunularin (LUNU)-producers and LUNU non-producers. In healthy volunteers (n = 195), resveratrol was reduced to dihydroresveratrol, which only in the LUNU-producer metabotype was sequentially dehydroxylated at the 5-position to yield LUNU and the 3-position to produce 4-hydroxydibenzyl. These metabolites (also 3,4'-dihydroxy-trans-stilbene in some LUNU-producers) were detected in the urine and (or) feces of 74% of volunteers after consuming resveratrol, while 26% lacked these dehydroxylase activities. The LUNU non-producer metabotype was more prevalent in females (P < 0.05) but independent of individuals' BMI and age. A 4-styrylphenol reductase in both metabotypes converted stilbenes to their corresponding dibenzyls, while no 4-dehydroxylation in stilbenes or dibenzyls was observed. 4-Hydroxy-trans-stilbene, pinosylvin, dihydropinosylvin, 3-hydroxydibenzyl, and 3-hydroxy-trans-stilbene were not detected in vivo or in vitro. Further research on LUNU metabotypes, their associated gut microbiota, and their impact on health is worthwhile.

Regulation of Anthocyanin Biosynthesis by Drought and UV-B Radiation in Wild Tomato (Solanum peruvianum) Fruit

Anthocyanins are plant pigments derived from the phenylpropanoid pathway which are produced in many different species, contributing to defense against stresses by their antioxidant properties. Cultivated tomatoes cannot synthesize flavonoids; however, wild tomatoes such as Solanum chilense and Solanum lycopersicoides have anthocyanin pigmented skin. Other wild tomato species such as Solanum peruvianum have been poorly studied concerning anthocyanin accumulation in the fruit. This research is the first to address the regulation of anthocyanin biosynthesis mediated by drought stress and light radiation in S. peruvianum fruit. Transcript accumulation of SpAN2, encoding for a key MYB type transcription factor for the regulation of anthocyanin biosynthesis, was induced in the fruit of plants exposed to drought treatment. In addition, fruit peel accumulates a greater anthocyanin content in water deficit-treated plants. The expression of SpAN2 was also regulated according to sunlight exposure, reaching a higher expression during maximal daily UV radiation and under controlled UV-B treatments. Similar results were observed for the expression of the late flavonoid biosynthetic gene dihydroflavonol 4-reductase (SpDFR). These results suggest that SpAN2 and SpDFR are involved in anthocyanin biosynthesis under drought stress and UV radiation in S. peruvianum.