The Bioavailability, Transport, and Bioactivity of Dietary Flavonoids: A Review from a Historical Perspective

Blueberry polyphenols alter gut microbiota & phenolic metabolism in rats

Consuming polyphenol-rich fruits and vegetables, including blueberries, is associated with beneficial health outcomes. Interest in enhancing polyphenol intakes via dietary supplements has grown, though differences in fruit versus supplement matrix on gut microbiota and ultimate phenolic metabolism to bioactive metabolites are unknown. To evaluate this, 5-month-old, ovariectomized, Sprague-Dawley rats were gavaged for 90 d with a purified extract of blueberry polyphenols (0, 50, 250, or 1000 mg total polyphenols per kg bw per d) or lyophilized blueberries (50 mg total polyphenols per kg bw per d, equivalent to 150 g fresh blueberries per day in humans). Urine, feces, and tissues were assessed for gut microbiota and phenolic metabolism. Significant dose- and food matrix-dependent effects were observed at all endpoints measured. Gut microbial populations showed increased diversity at moderate doses but decreased diversity at high doses. Urinary phenolic metabolites were primarily observed as microbially derived metabolites and underwent extensive host xenobiotic phase II metabolism. Thus, blueberry polyphenols in fruit and supplements induce differences in gut microbial communities and phenolic metabolism, which may alter intended health effects.

Flavonoids and hERG channels: Friends or foes?

The cardiac action potential is regulated by several ion channels. Drugs capable to block these channels, in particular the human ether-à-go-go-related gene (hERG) channel, also known as K_V11.1 channel, may lead to a potentially lethal ventricular tachyarrhythmia called "Torsades de Pointes". Thus, evaluation of the hERG channel off-target activity of novel chemical entities is nowadays required to safeguard patients as well as to avoid attrition in drug development. Flavonoids, a large class of natural compounds abundantly present in food, beverages, herbal medicines, and dietary food supplements, generally escape this assessment, though consumed in consistent amounts. Continuously growing evidence indicates that these compounds may interact with the hERG channel and block it. The present review, by examining numerous studies, summarizes the state-of-the-art in this field, describing the most significant examples of direct and indirect inhibition of the hERG channel current operated by flavonoids. A description of the molecular interactions between a few of these natural molecules and the Rattus norvegicus channel protein, achieved by an in silico approach, is also presented.

Current methodologies to refine bioavailability, delivery, and therapeutic efficacy of plant flavonoids in cancer treatment

Over the last two decades, several advancements have been made to improve the therapeutic efficacy of plant flavonoids, especially in cancer treatment. Factors such as low bioavailability, poor flavonoid stability and solubility, ineffective targeted delivery, and chemo-resistance hinder the application of flavonoids in anti-cancer therapy. Many anti-cancer compounds failed in the clinical trials because of unexpected altered clearance of flavonoids, poor absorption after administration, low efficacy, and/or adverse effects. Hence, the current research strategies are focused on improving the therapeutic efficacy of plant flavonoids, especially by enhancing their bioavailability through combination therapy, engineering gut microbiota, regulating flavonoids interaction with adenosine triphosphate binding cassette efflux transporters, and efficient delivery using nanocrystal and encapsulation technologies. This review aims to discuss different methodologies with examples from reported dietary flavonoids that showed an enhanced anti-cancer efficacy in both in vitro and in vivo models. Further, the review discusses the recent progress in biochemical modifications of flavonoids to improve bioavailability, solubility, and therapeutic efficacy.

Therapeutic strategies to overcome taxane resistance in cancer

One of the primary causes of attenuated or loss of efficacy of cancer chemotherapy is the emergence of multidrug resistance (MDR). Numerous studies have been published regarding potential approaches to reverse resistance to taxanes, including paclitaxel (PTX) and docetaxel, which represent one of the most important classes of anticancer drugs. Since 1984, following the FDA approval of paclitaxel for the treatment of advanced ovarian carcinoma, taxanes have been extensively used as drugs that target tumor microtubules. Taxanes, have been shown to affect an array of oncogenic signaling pathways and have potent cytotoxic efficacy. However, the clinical success of these drugs has been restricted by the emergence of cancer cell resistance, primarily caused by the overexpression of MDR efflux transporters or by microtubule alterations. In vitro and in vivo studies indicate that the mechanisms underlying the resistance to PTX and docetaxel are primarily due to alterations in α-tubulin and β-tubulin. Moreover, resistance to PTX and docetaxel results from: 1) alterations in microtubule-protein interactions, including microtubule-associated protein 4, stathmin, centriole, cilia, spindle-associated protein, and kinesins; 2) alterations in the expression and activity of multidrug efflux transporters of the ABC superfamily including P-glycoprotein (P-gp/ABCB1); 3) overexpression of anti-apoptotic proteins or inhibition of apoptotic proteins and tumor-suppressor proteins, as well as 4) modulation of signal transduction pathways associated with the activity of several cytokines, chemokines and transcription factors. In this review, we discuss the abovementioned molecular mechanisms and their role in mediating cancer chemoresistance to PTX and docetaxel. We provide a detailed analysis of both in vitro and in vivo experimental data and describe the application of these findings to therapeutic practice. The current review also discusses the efficacy of different pharmacological modulations to achieve reversal of PTX resistance. The therapeutic roles of several novel compounds, as well as herbal formulations, are also discussed. Among them, many structural derivatives had efficacy against the MDR phenotype by either suppressing MDR or increasing the cytotoxic efficacy compared to the parental drugs, or both. Natural products functioning as MDR chemosensitizers offer novel treatment strategies in patients with chemoresistant cancers by attenuating MDR and increasing chemotherapy efficacy. We broadly discuss the roles of inhibitors of P-gp and other efflux pumps, in the reversal of PTX and docetaxel resistance in cancer cells and the significance of using a nanomedicine delivery system in this context. Thus, a better understanding of the molecular mechanisms mediating the reversal of drug resistance, combined with drug efficacy and the application of target-based inhibition or specific drug delivery, could signal a new era in modern medicine that would limit the pathological consequences of MDR in cancer patients.

Flavonoids against the SARS-CoV-2 induced inflammatory storm

The disease severity of COVID-19, especially in the elderly and patients with co-morbidities, is characterized by hypercytokinemia, an exaggerated immune response associated with an uncontrolled and excessive release of proinflammatory cytokine mediators (cytokine storm). Flavonoids, important secondary metabolites of plants, have long been studied as therapeutic interventions in inflammatory diseases due to their cytokine-modulatory effects. In this review, we discuss the potential role of flavonoids in the modulation of signaling pathways that are crucial for COVID-19 disease, particularly those related to inflammation and immunity. The immunomodulatory ability of flavonoids, carried out by the regulation of inflammatory mediators, the inhibition of endothelial activation, NLRP3 inflammasome, toll-like receptors (TLRs) or bromodomain containing protein 4 (BRD4), and the activation of the nuclear factor erythroid-derived 2-related factor 2 (Nrf2), might be beneficial in regulating the cytokine storm during SARS-CoV-2 infection. Moreover, the ability of flavonoids to inhibit dipeptidyl peptidase 4 (DPP4), neutralize 3-chymotrypsin-like protease (3CL^pro) or to affect gut microbiota to maintain immune response, and the dual action of angiotensin-converting enzyme 2 (ACE-2) may potentially also be applied to the exaggerated inflammatory responses induced by SARS-CoV-2. Based on the previously proven effects of flavonoids in other diseases or on the basis of newly published studies associated with COVID-19 (bioinformatics, molecular docking), it is reasonable to assume positive effects of flavonoids on inflammatory changes associated with COVID-19. This review highlights the current state of knowledge of the utility of flavonoids in the management of COVID-19 and also points to the multiple biological effects of flavonoids on signaling pathways associated with the inflammation processes that are deregulated in the pathology induced by SARS-CoV-2. The identification of agents, including naturally occurring substances such as flavonoids, represents great approach potentially utilizable in the management of COVID-19. Although not clinically investigated yet, the applicability of flavonoids against COVID-19 could be a promising strategy due to a broad spectrum of their biological activities.

Phytobiotics to improve health and production of broiler chickens: functions beyond the antioxidant activity

Phytobiotics, also known as phytochemicals or phytogenics, have a wide variety of biological activities and have recently emerged as alternatives to synthetic antibiotic growth promoters. Numerous studies have reported the growth-promoting effects of phytobiotics in chickens, but their precise mechanism of action is yet to be elucidated. Phytobiotics are traditionally known for their antioxidant activity. However, extensive investigations have shown that these compounds also have anti-inflammatory, antimicrobial, and transcription-modulating effects. Phytobiotics are non-nutritive constituents, and their bioavailability is low. Nonetheless, their beneficial effects have been observed in several tissues or organs. The health benefits of the ingestion of phytobiotics are attributed to their antioxidant activity. However, several studies have revealed that not all these benefits could be explained by the antioxidant effects alone. In this review, I focused on the bioavailability of phytobiotics and the possible mechanisms underlying their overall effects on intestinal barrier functions, inflammatory status, gut microbiota, systemic inflammation, and metabolism, rather than the specific effects of each compound. I also discuss the possible mechanisms by which phytobiotics contribute to growth promotion in chickens.

Low Molecular Weight (poly)Phenol Metabolites Across the Blood-Brain Barrier: The Underexplored Journey

The world of (poly)phenols arising from dietary sources has been significantly amplified with the discovery of low molecular weight (LMW) (poly)phenol metabolites resulting from phase I and phase II metabolism and microbiota transformations. These metabolites, which are known to reach human circulation have been studied to further explore their interesting properties, especially regarding neuroprotection. Nevertheless, once in circulation, their distribution to target tissues, such as the brain, relies on their ability to cross the blood-brain barrier (BBB), one of the most controlled barriers present in humans. This represents a key step of an underexplored journey towards the brain. Present review highlights the main findings related to the ability of LMW (poly)phenol metabolites to reach the brain, considering different studies: in silico, in vitro, and in vivo. The mechanisms associated with the transport of these LMW (poly)phenol metabolites across the BBB and possible transporters will be discussed. Overall, the transport of these LMW (poly)phenol metabolites is crucial to elucidate which compounds may exert direct neuroprotective effects, so it is imperative to continue dissecting their potential to cross the BBB and the mechanisms behind their permeation.

Dietary Factors and Prostate Cancer Development, Progression, and Reduction

Due to the constantly increasing number of cases, prostate cancer has become one of the most important health problems of modern societies. This review presents the current knowledge regarding the role of nutrients and foodstuff consumption in the etiology and development of prostate malignancies, including the potential mechanisms of action. The results of several in vivo and in vitro laboratory experiments as well as those reported by the clinical and epidemiological research studies carried out around the world were analyzed. The outcomes of these studies clearly show the influence of both nutrients and food products on the etiology and prevention of prostate cancer. Consumption of certain nutrients (saturated and trans fatty acids) and food products (e.g., processed meat products) leads to the disruption of prostate hormonal regulation, induction of oxidative stress and inflammation, and alteration of growth factor signaling and lipid metabolism, which all contribute to prostate carcinogenesis. On the other hand, a high consumption of vegetables, fruits, fish, and whole grain products exerts protective and/or therapeutic effects. Special bioactive functions are assigned to compounds such as flavonoids, stilbenes, and lycopene. Since the influence of nutrients and dietary pattern is a modifiable risk factor in the development and prevention of prostate cancer, awareness of the beneficial and harmful effects of individual food ingredients is of great importance in the global strategy against prostate cancer.

Antioxidant properties and phenolic profiling by UPLC-QTOF-MS of Ajwah, Safawy and Sukkari cultivars of date palm

Date palm (P. dactylifera) plays a vital role in ethnomedicinal practices in several parts of the world. There are over 2000 cultivars of date palm that differ in chemical composition and extent of bioactivity. The present study was undertaken to comparatively evaluate the antioxidant potential of three cultivars of date palm (Ajwah, Safawy and Sukkari) from Saudi Arabia and analyze their phenolic constituents in order to draw a rationale for their activity. Antioxidant activities of the date cultivars were evaluated by different quantitative methods including 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging assay, total antioxidant capacity, reducing power, total phenolic (TPC), flavonoid (TFC) and tannin content (TTC), while qualitative phenolic composition was determined using ultra performance liquid chromatography coupled to quadropole time of flight mass spectrometry (UPLC-QTOF-MS). All the three date extracts showed good DPPH radical scavenging (IC₅₀ 103–177 μg/mL) and hydroxyl radical scavenging (IC₅₀ 1.1–1.55 mg/mL) activity and total antioxidant capacity (IC₅₀ 87–192 μg/mL). The reducing power was also comparable to that of ascorbic acid, used as standard in above experiments. All the three samples contain significant amount of major antioxidant components (phenolic, flavonoid and tannin) that successfully correlates with the results of radical scavenging assays. UPLC-QTOF-MS revealed a total of 22 compounds in these date cultivars classified into common phenolics, flavonoids, sterols and phytoestrogens. Significant variation in the degree of antioxidant activity of these three date cultivars can be attributed to the difference in the content and composition of phenolic compounds.

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Ajwah, Safawy and Sukkari date palm possess significant amount of natural antioxidant components.

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Dietary intake of Ajwah, Safawy and Sukkari date palm can prevent a number of oxidative damage mediated diseases.

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The common phenolics, flavonoids, sterols and phytoestrogens of date palm might contributed in the prevention of diseases.

Stratification of Volunteers According to Flavanone Metabolite Excretion and Phase II Metabolism Profile after Single Doses of 'Pera' Orange and 'Moro' Blood Orange Juices

Large interindividual variations in the biological response to citrus flavanones have been observed, and this could be associated with high variations in their bioavailability. The aim of this study was to identify the main determinants underlying interindividual differences in citrus flavanone metabolism and excretion. In a randomized cross-over study, non-obese and obese volunteers, aged 19-40 years, ingested single doses of Pera and Moro orange juices, and urine was collected for 24 h. A large difference in the recovery of the urinary flavanone phase II metabolites was observed, with hesperetin-sulfate and hesperetin-sulfo-O-glucuronide being the major metabolites. Subjects were stratified according to their total excretion of flavanone metabolites as high, medium, and low excretors, but the expected correlation with the microbiome was not observed at the genus level. A second stratification was proposed according to phase II flavanone metabolism, whereby participants were divided into two excretion groups: Profiles A and B. Profile B individuals showed greater biotransformation of hesperetin-sulfate to hesperetin-sulfo-O-glucuronide, as well as transformation of flavanone-monoglucuronide to the respective diglucuronides, suggestive of an influence of polymorphisms on UDP-glucuronosyltransferase. In conclusion, this study proposes a new stratification of volunteers based on their metabolic profiles. Gut microbiota composition and polymorphisms of phase II enzymes may be related to the interindividual variability of metabolism.

Okra (Abelmoschus Esculentus) as a Potential Dietary Medicine with Nutraceutical Importance for Sustainable Health Applications

Recently, there has been a paradigm shift from conventional therapies to relatively safer phytotherapies. This divergence is crucial for the management of various chronic diseases. Okra (Abelmoschus esculentus L.) is a popular vegetable crop with good nutritional significance, along with certain therapeutic values, which makes it a potential candidate in the use of a variety of nutraceuticals. Different parts of the okra fruit (mucilage, seed, and pods) contain certain important bioactive components, which confer its medicinal properties. The phytochemicals of okra have been studied for their potential therapeutic activities on various chronic diseases, such as type-2 diabetes, cardiovascular, and digestive diseases, as well as the antifatigue effect, liver detoxification, antibacterial, and chemo-preventive activities. Moreover, okra mucilage has been widely used in medicinal applications such as a plasma replacement or blood volume expanders. Overall, okra is considered to be an easily available, low-cost vegetable crop with various nutritional values and potential health benefits. Despite several reports about its therapeutic benefits and potential nutraceutical significance, there is a dearth of research on the pharmacokinetics and bioavailability of okra, which has hampered its widespread use in the nutraceutical industry. This review summarizes the available literature on the bioactive composition of okra and its potential nutraceutical significance. It will also provide a platform for further research on the pharmacokinetics and bioavailability of okra for its possible commercial production as a therapeutic agent against various chronic diseases.

Hesperetin's health potential: moving from preclinical to clinical evidence and bioavailability issues, to upcoming strategies to overcome current limitations

Flavonoids are common in the plant kingdom and many of them have shown a wide spectrum of bioactive properties. Hesperetin (Hst), the aglycone form of hesperidin, is a great example, and is the most abundant flavonoid found in Citrus plants. This review aims to provide an overview on the in vitro, in vivo and clinical studies reporting the Hst pharmacological effects and to discuss the bioavailability-related issues. Preclinical studies have shown promising effects on cancer, cardiovascular diseases, carbohydrate dysregulation, bone health, and other pathologies. Clinical studies have supported the Hst promissory effects as cardioprotective and neuroprotective agent. However, further well-designed clinical trials are needed to address the other Hst effects observed in preclinical trials, as well as to a more in-depth understanding of its safety profile.

Ex vivo fecal fermentation of human ileal fluid collected after raspberry consumption modifies (poly)phenolics and modulates genoprotective effects in colonic epithelial cells

Diets rich in fruit and vegetables are associated with a decreased incidence of colorectal cancer (CRC) due, in part, to the bioactive (poly)phenolic components and their microbiota-mediated metabolites. This study investigated how such compounds, derived from ingested raspberries in the gastrointestinal tract, may exert protective effects by reducing DNA damage. Ileal fluids collected pre- and post-consumption of 300 g of raspberries by ileostomists (n = 11) were subjected to 24 h ex vivo fermentation with fecal inoculum to simulate interaction with colonic microbiota. The impact of fermentation on (poly)phenolics in ileal fluid was determined and the bioactivity of ileal fluids pre- and post fermentation investigated. (Poly)phenolic compounds including sanguiin H-6, sanguiin H-10 and cyanidin-3-O-sophoroside decreased significantly during fermentation while, in contrast, microbial catabolites, including 3-(3′-hydroxyphenyl)propanoic acid, 3-hydroxybenzoic acid and benzoic acid increased significantly. The post-raspberry ileal fermentate from 9 of the 11 ileostomates significantly decreased DNA damage (~30%) in the CCD 841 CoN normal cell line using an oxidative challenge COMET assay. The raspberry ileal fermentates also modulated gene expression of the nuclear factor 2–antioxidant responsive element (Nrf2-ARE) pathway involved in oxidative stress cytoprotection, namely Nrf2, NAD(P)H dehydrogenase, quinone-1 and heme oxygenase-1. Four of the phenolic catabolites were assessed individually, each significantly reducing DNA damage from an oxidative challenge over a physiologically relevant 10–100 μM range. They also induced a differential pattern of expression of key genes in the Nrf2-ARE pathway in CCD 841 CoN cells. The study indicates that the colon-available raspberry (poly)phenols and their microbial-derived catabolites may play a role in protection against CRC in vivo.

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Health effects of dietary (poly)phenols linked to interactions within the GI tract.

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Ileostomy-based bioavailability studies allow effective interrogation of the GI tract.

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Fecal fermentation of raspberry-enriched ileal fluid, increases phenolic content.

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Raspberry ileal fluid fermentates & phenolic acids reduce DNA damage in colonocytes.

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Cytoprotective Nrf2-ARE pathway modulated by ileal fluid fermentates & phenolic acids.

An enriched biosignature of gut microbiota-dependent metabolites characterizes maternal plasma in a mouse model of fetal alcohol spectrum disorder

Prenatal alcohol exposure (PAE) causes permanent cognitive disability. The enteric microbiome generates microbial-dependent products (MDPs) that may contribute to disorders including autism, depression, and anxiety; it is unknown whether similar alterations occur in PAE. Using a mouse PAE model, we performed untargeted metabolome analyses upon the maternal–fetal dyad at gestational day 17.5. Hierarchical clustering by principal component analysis and Pearson’s correlation of maternal plasma (813 metabolites) both identified MDPs as significant predictors for PAE. The majority were phenolic acids enriched in PAE. Correlational network analyses revealed that alcohol altered plasma MDP-metabolite relationships, and alcohol-exposed maternal plasma was characterized by a subnetwork dominated by phenolic acids. Twenty-nine MDPs were detected in fetal liver and sixteen in fetal brain, where their impact is unknown. Several of these, including 4-ethylphenylsulfate, oxindole, indolepropionate, p-cresol sulfate, catechol sulfate, and salicylate, are implicated in other neurological disorders. We conclude that MDPs constitute a characteristic biosignature that distinguishes PAE. These MDPs are abundant in human plasma, where they influence physiology and disease. Their altered abundance here may reflect alcohol’s known effects on microbiota composition and gut permeability. We propose that the maternal microbiome and its MDPs are a previously unrecognized influence upon the pathologies that typify PAE.

Higher habitual flavonoid intakes are associated with a lower risk of peripheral artery disease hospitalizations

BACKGROUND

The role of nutrition in the primary prevention of peripheral artery disease (PAD), the third leading cause of atherosclerotic cardiovascular disease, is undetermined. Flavonoids may attenuate atherosclerosis and therefore persons who consume flavonoid-rich foods may have a lower risk of developing PAD.

OBJECTIVES

We aimed to examine the association between flavonoid intake and PAD hospitalizations and investigate if the association differs according to established risk factors for PAD.

METHODS

Baseline data from 55,647 participants of the Danish Diet, Cancer, and Health Study without PAD, recruited from 1993 to 1997, were cross-linked with Danish nationwide registries. Flavonoid intake was calculated from FFQs using the Phenol-Explorer database. Associations were examined using multivariable-adjusted restricted cubic splines based on Cox proportional hazards models.

RESULTS

After a median [IQR] follow-up time of 21 [20-22] y, 2131 participants had been hospitalized for any PAD. The association between total flavonoid intake and total PAD hospitalizations was nonlinear, reaching a plateau at ∼750-1000 mg/d. Compared with the median flavonoid intake in quintile 1 (174 mg/d), an intake of 1000 mg/d was associated with a 32% lower risk of any PAD hospitalization (HR: 0.68; 95% CI: 0.60, 0.77), a 26% lower risk of atherosclerosis (HR: 0.74; 95% CI: 0.62, 0.88), a 28% lower risk of an aneurysm (HR: 0.72; 95% CI: 0.59, 0.88), and a 47% lower risk of a hospitalization for other peripheral vascular disease (HR: 0.53; 95% CI: 0.42, 0.67). A higher total flavonoid intake was also significantly associated with a lower incidence of revascularization or endovascular surgery and lower extremity amputation. The association between total flavonoid intake and PAD hospitalizations differed according to baseline smoking status, alcohol intake, BMI, and diabetes status.

CONCLUSIONS

Ensuring the adequate consumption of flavonoid-rich foods, particularly in subpopulations prone to the development of atherosclerosis, may be a key strategy to lower the risk of PAD.

Flavonoids in myocardial ischemia-reperfusion injury: Therapeutic effects and mechanisms

Ischemic heart diseases are one of the major causes of death worldwide. Effective restoration of blood flow can significantly improve patients' quality of life and reduce mortality. However, reperfusion injury cannot be ignored. Flavonoids possess well-established antioxidant properties; They also have other benefits that may be relevant for ameliorating myocardial ischemia-reperfusion injury (MIRI). In this review, we focus on flavonoids with cardiovascular-protection function and emphasize their pharmacological effects. The main mechanisms of flavonoid pharmacological activities against MIRI involve the following aspects: a) antioxidant, b) anti-inflammatory, c) anti-platelet aggregation, d) anti-apoptosis, and e) myocardial-function regulation activities. We also summarized the effectiveness of flavonoids for MIRI.

Assessment of binding interaction dihydromyricetin and myricetin with bovine lactoferrin and effects on antioxidant activity

The binding interactions of bovine lactoferrin (BLF) with two flavonoids dihydromyricetin (DMY) and myricetin (MY) were investigated by the multi-spectroscopic, microscale thermophoresis (MST) techniques, molecular docking, and then their antioxidant activities were studied by detection of free radical scavenging activity against DPPH. Results of UV-vis and fluorescence spectroscopies showed that DMY/MY and BLF formed the ground state complex through the static quenching mechanism. Moreover, MY with more planar stereochemical structure had higher affinity for BLF than DMY with twisted stereochemical structure, according to the binding constant (K_b), free energy change (ΔG°), dissociation constant (K_d) and donor-acceptor distance (r). Thermodynamic parameters revealed that hydrogen bond and van der Waals force were major forces in the formation of BLF-DMY complex, while hydrophobic interactions played major roles in the formation of BLF-DMY complex. The circular dichroism (CD) study indicated that MY induced more conformational change in BLF than DMY. Furthermore, molecular modeling provided insights into the difference of binding interactions between BLF and two flavonoids. Finally, the radical scavenging activity assays indicated the presence of BLF delayed the decrease in antioxidant capacities of two flavonoids. These results were helpful to understand the binding mechanism and biological effects of non-covalent BLF-flavonoid interaction.

Short-Term Tea Consumption Is Not Associated with a Reduction in Blood Lipids or Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

A recent systematic review of epidemiological evidence suggests that higher amounts of tea intake are associated with lower risks of cardiovascular disease (CVD) incidence and mortality.

OBJECTIVES

Our study objective was to assess mechanisms by which tea consumption may influence CVD risks.

METHODS

A systematic review and meta-analysis was conducted to investigate the effects of green and/or black tea consumption (≥4 wk) on systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol, LDL cholesterol, HDL cholesterol, and triglyceride (TG) in healthy populations and among at-risk adults (analyzed separately) with metabolic syndrome, prediabetes, and hypercholesterolemia. The Grading of Recommendations Assessment, Development and Evaluation approach was used to rate the strength of evidence (SoE).

RESULTS

A total of 14 unique RCTs which randomly assigned 798 participants to either green tea, black tea, or placebo controls were included in our analyses. Intervention durations ranged from 4 to 24 wk (mean: 7.4 wk). Individual studies were judged as moderate to high quality based on risk of bias assessments. SoE was low to moderate owing to low sample sizes and insufficient power for most included studies to observe changes in the measured CVD biomarkers. Meta-analyses showed no significant effects of tea consumption on SBP, DBP, total cholesterol, LDL cholesterol, HDL cholesterol, and TG in healthy and at-risk adults (i.e., adults with obesity, prediabetes, borderline hypercholesterolemia, and metabolic syndrome).

CONCLUSIONS

Short-term (4-24 wk) tea consumption does not appear to significantly affect blood pressure or lipids in healthy or at-risk adults, although the evidence is limited by insufficient power to detect changes in these CVD biomarkers. High-quality RCTs with longer durations and sufficient sample sizes are needed to fully elucidate the effects of tea. This systematic review was registered at www.crd.york.ac.uk/prospero/ as CRD42020134513.

In Vitro Gastrointestinal Digestion and Colonic Catabolism of Mango (Mangifera indica L.) Pulp Polyphenols

Mango (Mangifera indica L.), a fruit with sensorial attractiveness and extraordinary nutritional and phytochemical composition, is one of the most consumed tropical varieties in the world. A growing body of evidence suggests that their bioactive composition differentiates them from other fruits, with mango pulp being an especially rich and diverse source of polyphenols. In this study, mango pulp polyphenols were submitted to in vitro gastrointestinal digestion and colonic fermentation, and aliquots were analyzed by HPLC-HRMS. The main phenolic compounds identified in the mango pulp were hydroxybenzoic acid-hexoside, two mono-galloyl-glucoside isomers and vanillic acid. The release of total polyphenols increased after the in vitro digestion, with an overall bioaccessibility of 206.3%. Specifically, the most bioaccessible mango polyphenols were gallic acid, 3-O-methylgallic acid, two hydroxybenzoic acid hexosides, methyl gallate, 3,4-dihydroxybenzoic acid and benzoic acid, which potentially cross the small intestine reaching the colon for fermentation by the resident microbiota. After 48 h of fecal fermentation, the main resultant mango catabolites were pyrogallol, gallic and 3,4-dihydroxybenzoic acids. This highlighted the extensive transformation of mango pulp polyphenols through the gastrointestinal tract and by the resident gut microbiota, with the resultant formation of mainly simple phenolics, which can be considered as biomarkers of the colonic metabolism of mango.

Flavonoid intake and its association with atrial fibrillation

BACKGROUND & AIMS

Primary prevention of atrial fibrillation (AF) through behavioural and dietary modification is a critically important and unmet need. Flavonoids are bioactive dietary compounds with promising cardiovascular health benefits. Our aim was to investigate the association between flavonoid intake and clinically apparent AF.

METHODS

Baseline data from 55 613 participants of the Danish Diet, Cancer and Health Study, without AF, recruited between 1993 and 1997, were cross-linked with Danish nationwide registries. Total flavonoid and flavonoid subclass intakes were calculated from validated food frequency questionnaires using the Phenol-Explorer database. Associations between flavonoid intake and incident AF (first-time hospitalization or outpatient visit) were examined using restricted cubic splines based on Cox proportional hazards models.

RESULTS

During a median [IQR] follow-up of 21 [18-22] years, 7291 participants were diagnosed with AF. Total flavonoid intake was not statistically significantly associated with risk of incident AF in the whole cohort. However, compared to the lowest quintile, a total flavonoid intake of 1000 mg/day was associated with a lower risk of AF in smokers [0.86 (0.77, 0.96)] but not in non-smokers [0.96 (0.88, 1.06)], and a lower risk of AF in high alcohol consumers [>20 g/d: 0.84 (0.75, 0.95)] but not in low-to-moderate alcohol consumers [<20 g/d: 0.97 (0.89, 1.07)].

CONCLUSION

Intake of flavonoids was not significantly associated with a lower risk of incident AF. However, higher intakes of flavonoids may be beneficial for those at a higher risk of developing AF.

Influence of linseed and antioxidant-rich diets in pig nutrition on lipid oxidation during cooking and in vitro digestion of pork

Enrichment of pig diets with polyunsaturated fatty acids (PUFA) is considered an emerging strategy to increase their intake in the human diet. However, PUFA are particularly vulnerable to oxidative reactions leading to the generation of toxic compounds. The aim of this study was to evaluate the effect of supplementation of pig diets with extruded linseed (L), either or not in combination with synthetic antioxidants (E, tocopheryl-acetate and selenium) or natural extracts (P, grape-skin and oregano), and basal diet (C, without linseed) on the oxidative stability in raw, grilled and in vitro digested pork. The diet supplementation with antioxidant-rich ingredients resulted in the accumulation of specific metabolites in meat. Actually, 11 different phenolic- and 6 tocopherol-derived metabolites were identified by UHPLC/HR-MS. These metabolites were potentially correlated with the reduction in the oxidative phenomena occurring during meat cooking and digestion. Specifically, 16% and 35% reduction in the amounts of lipid hydroperoxides and TBA-RS were assessed after cooking of meat from P diet, respect to the L diet. Diet supplementations with α-tocopheryl acetate and selenium reduced the oxidative reactions only during meat cooking. A significant reduction was attended at the end of in vitro digestion, showing about 24% and 34% hydroperoxides and TBA-RS concentration reductions, respectively, in P diet samples respect to the L ones. Thus, our study suggests that the appearance of phenolic metabolites in meat could be associated to a reduction in the oxidative phenomena during meat cooking and digestion.

In vitro catabolism of 3',4'-dihydroxycinnamic acid by human colonic microbiota

3',4'-Dihydroxycinnamic acid (aka caffeic acid) is a common dietary component found in a variety of plant-derived food products either in a free form or esterified as in chlorogenic acids such as 5-O-caffeoylquinic acid. The dihydroxycinnamate is produced principally by hydrolysis in the colon of 5-O-caffeoylquinic acid and other caffeoylquinic acid esters, and is catabolised by the resident microbiota prior to absorption. In the present study 3',4'-dihydroxycinnamic acid was incubated in vitro, with or without glucose, under anaerobic conditions with faecal slurries obtained from five volunteers. The main resultant catabolites to accumulate were 3-(3',4'-dihydroxyphenyl)propanoic acid (aka dihydrocaffeic acid), 3-(3'-hydroxyphenyl)propanoic acid and phenylacetic acid. Both the rate of degradation of the hydroxycinnamate substrate and the catabolite profile varied between the faecal samples from the individual volunteers. Overall there was no clear cut effect when glucose was added to incubation medium.

De Novo Biosynthesis of Multiple Pinocembrin Derivatives in Saccharomyces cerevisiae

Pinocembrin derived flavones are the major bioactive compounds presented in the Lamiaceae plants that have long been of interest due to their great pharmaceutical and economical significance. Modifications on the central skeleton of the flavone moiety have a huge impact on their biological activities. However, the enzymes responsible for structure modification of most flavones are either inefficient or remain unidentified. By integrating omics analysis of Scutellaria barbata and synthetic biology tools in yeast chassis, we characterized a novel gene encoding flavone 7-O-methyltransferase (F7OMT) and discovered a new flavone 8-hydroxylase (F8H) with increased activity. We also identified a series of flavone 6-hydroxylases (F6Hs) and flavone 8-O-methyltransferases (F8OMTs) in this study. Subsequently, we constructed the biosynthetic pathway for chrysin production by assembling catalytic elements from different species and improved the titer to 10.06 mg/L. Using the established chrysin production platform, we achieved the de novo biosynthesis of baicalein, baicalin, norwogonin, wogonin, isowogonin, and moslosooflavone in yeast. Our results indicated that the combination of omics and synthetic biology can greatly speed up the efficiency of gene mining in plants and the engineered yeasts established an alternative way for the production of pinocembrin derivatives.

Plasma pharmacokinetics of (poly)phenol metabolites and catabolites after ingestion of orange juice by endurance trained men

The health benefits of orange juice (OJ) consumption are attributed in part to the circulating flavanone phase II metabolites and their microbial-derived ring fission phenolic catabolites. The present study investigated these compounds in the bloodstream after acute intake of 500 mL of OJ. Plasma samples obtained at 0, 1, 2, 3, 4, 5, 6, 7, 8 and 24 h after OJ intake were analysed by HPLC-HR-MS. Eleven flavanone metabolites and 36 phenolic catabolites were identified and quantified in plasma. The main metabolites were hesperetin-3'-sulfate with a peak plasma concentration (C_max) of 80 nmol/L, followed by hesperetin-7-glucuronide (C_max 24 nmol/L), hesperetin-3'-glucuronide (C_max 18 nmol/L) and naringenin-7-glucuronide (C_max 21 nmol/L). Among the main phenolic catabolites to increase in plasma after OJ consumption were 3'-methoxycinnamic acid-4'-sulfate (C_max 19 nmol/L), 3-hydroxy-3-(3'-hydroxy-4'-methoxyphenyl)propanoic acid (C_max 20 nmol/L), 3-(3'-hydroxy-4'-methoxyphenyl)propanoic acid (C_max 19 nmol/L), 3-(4'-hydroxyphenyl)propanoic acid (C_max 25 nmol/L), and 3-(phenyl)propanoic acid (C_max 19 nmol/L), as well as substantial amounts of phenylacetic and hippuric acids. The comprehensive plasma pharmacokinetic profiles that were obtained are of value to the design of future ex vivo cell studies, aimed at elucidating the mechanisms underlying the potential health benefits of OJ consumption. CLINICAL TRIAL REGISTRATION NUMBER: This trial was registered at clinicaltrials.gov as NCT02627547.

Fabrication and characterization of dihydromyricetin encapsulated zein-caseinate nanoparticles and its bioavailability in rat

Dihydromyricetin (DMY) encapsulated zein-caseinate nanoparticles (DZP) were fabricated by antisolvent method. The encapsulation and loading efficiency of DMY in DZP were 90.2% and 22.6% as determined by HPLC. DZP is spherical with particle size and ζ potential of 206.4 nm and -29.6 mV, respectively. Physicochemical characterization showed that DMY existed in amorphous form in DZP and its interaction with proteins was found. The fabrication of DZP significantly improved the stability of DMY. Besides, the diffusion rate of DMY in DZP was faster than its suspensions in both simulated gastric and intestinal fluid. The adhesion of DMY in mice gastrointestinal tract was also improved. Besides DMY itself, its methylated metabolites with further sulfation and glucuronide were identified in rat plasma by UPLC-QTOF-MS. UPLC-QqQ-MS/MS quantitative analysis showed that the oral bioavailability of DMY was 1.95 times enhanced. Besides, the concentration of DMY metabolites in plasma were all increased.

Citrus flavonoids and the intestinal barrier: Interactions and effects

The intestinal barrier plays a central role in sustaining gut homeostasis and, when dysfunctional, may contribute to diseases. Dietary flavonoids derived from Citrus genus represent one of the main naturally occurring phytochemicals with multiple potential benefits for the intestinal barrier function. In the intestine, citrus flavonoids (CFs) undergo ingestion from the lumen, biotransformation in the epithelial cells and/or crosstalk with luminal microbiota to afford various metabolites that may in turn exert protective actions on gut barrier along with their parental compounds. Specifically, the health-promoting properties of CFs and their metabolic bioactives for the intestinal barrier include their capacity to (a) modulate barrier permeability; (b) protect mucus layer; (c) regulate intestinal immune system; (d) fight against oxidative stress; and (e) positively shape microbiome and metabolome. Notably, local effects of CFs can also generate systemic benefits, for instance, improvement of gut microbial dysbiosis helpful to orchestrate gut homeostasis and leading to alleviation of systemic dysmetabolism. Given the important role of the intestinal barrier in overall health, further understanding of underlying action mechanisms and ultimate health effects of CFs as well as their metabolites on the intestine is of great significance to future application of citrus plants and their bioactives as dietary supplements and/or functional ingredients in medical foods.

Postexercise Inflammasome Activation and IL-1β Production Mitigated by Flavonoid Supplementation in Cyclists

Inflammasomes are multiprotein signaling platforms of the innate immune system that detect markers of physiological stress and promote the maturation of caspase-1 and interleukin 1 beta (IL-1β), IL-18, and gasdermin D. This randomized, cross-over trial investigated the influence of 2-week mixed flavonoid (FLAV) versus placebo (PL) supplementation on inflammasome activation and IL-1β and IL-18 production after 75-km cycling in 22 cyclists (42 ± 1.7 years). Blood samples were collected before and after the 2-week supplementation, and then 0 hr, 1.5 hr, and 21 hr postexercise (176 ± 5.4 min, 73.4 ± 2.0 %VO2max). The supplement (678 mg FLAVs) included quercetin, green tea catechins, and bilberry anthocyanins. The pattern of change in the plasma levels of the inflammasome adaptor oligomer ASC (apoptosis-associated speck-like protein containing caspase recruitment domain) was different between the FLAV and PL trials, with the FLAV ASC levels 52% lower (Cohen's d = 1.06) than PL immediately following 75-km cycling (interaction effect, p = .012). The plasma IL-1β levels in FLAV were significantly lower than PL (23-42%; Cohen's d = 0.293-0.644) throughout 21 hr of recovery (interaction effect, p = .004). The change in plasma gasdermin D levels were lower immediately postexercise in FLAV versus PL (15% contrast, p = .023; Cohen's d = 0.450). The patterns of change in plasma IL-18 and IL-37 did not differ between the FLAV and PL trials (interaction effects, p = .388, .716, respectively). These data indicate that 2-week FLAV ingestion mitigated inflammasome activation, with a corresponding decrease in IL-1β release in cyclists after a 75-km cycling time trial. The data from this study support the strategy of ingesting high amounts of FLAV to mitigate postexercise inflammation.

Stability and anti-topoisomerase activity of phenolic compounds of Capsicum annuum "Serrano" after gastrointestinal digestion and in vitro colonic fermentation

"Serrano" pepper is extensively used in Mexican cuisine. The aim of this study was to identify the bioaccessible phenolic compounds (PC) of "Serrano" pepper as well as short-chain fatty acids (SCFA) produced and PC bioconverted using an in vitro step-wise gastromimetic model of the intestinal digestion and anaerobic fermentation of the isolated indigestible fraction (IF). The anti-topoisomerase activity of the fermented samples was also evaluated. PC bioaccessibility was about 45% in the small intestine. Chlorogenic acid and capsaicin were identified during the intestinal digestion, while quercetin was identified as available to the gut microbiota. After 48-h fermentation, SCFA molar ratio was 77:11:12 for acetic, propionic and butyric acid. The PC identified in IF and after 12 h of fermentation showed anti-topoisomerase activity. A synergistic effect among the PC and gut metabolites mixture was observed, which indicates a possible antiproliferative mechanism that should be tested in further studies.

Intestinal Organoids: A Tool for Modelling Diet-Microbiome-Host Interactions

Dietary patterns, microbiome dysbiosis, and gut microbial metabolites (GMMs) have a pivotal role in the homeostasis of intestinal epithelial cells and in disease progression, such as that of colorectal cancer (CRC). Although GMMs and microorganisms have crucial roles in many biological activities, models for deciphering diet-microbiome-host relationships are largely limited to animal models. Thus, intestinal organoids (IOs) have provided unprecedented opportunities for the generation of in vitro platforms with the sufficient level of complexity to model physiological and pathological diet-microbiome-host conditions. Overall, IO responses to GMM metabolites and microorganisms can provide new insights into the mechanisms by which those agents may prevent or trigger diseases, significantly extending our knowledge of diet-microbiome-host interactions.

Broaden the sugar donor selectivity of blackberry glycosyltransferase UGT78H2 through residual substitutions

Glycosylated secondary metabolites constitute a large proportion of nutrients or ingredients in consumed plants and related products. The glycosyl decoration largely depends on the activity of plant UDP-glycosyltransferases (UGTs). Mechanisms underlying the substrate selectivity and specificity of these reactions remain elusive. Here we report the cloning and functional characterization of a UGT, UGT78H2 in blackberry fruits. In vitro enzyme substrate specificity analysis and enzymatic kinetics evidenced that UGT78H2 glycosylate exclusively quercetin using uridine-5' diphosphate glucuronic acid (UDP-glucuronic acid) and uridine-5' diphosphate galactose (UDP-galactose). Site-directed mutagenesis was introduced into two residuals (N340P, K360N) previously unexplored. The mutation enhanced the protein catalyzing efficiency, especially toward UDP-galactose (23% higher), and expanded the sugar donor selectivity, which can use UDP-glucose as well. Molecular modeling and biochemical analysis results enable identification of the 23rd residue (360th in UGT78H2) of the PSPG (plant secondary product glycosyltransferase) motif as a key residue in defining this sugar selecting spectrum. Additionally, promoter of UGT78H2 was obtained. Transgenic analysis using the UGT78H2pro::GUS reporter system demonstrated that transcripts controlled by the promoter predominantly expressed in younger tissues. Subcellular localization study revealed that UGT78H2 was a soluble protein in the nucleus and cytoplasm. These results clarified the bio-function of UGT78H2 and provided a valid approach for substrate selectivity modification in horticultural plants, particularly for sugar donor selectivity.

Effect and Comparison of Luteolin and Its Derivative Sodium Luteolin-4'-sulfonate on Adipogenic Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells through AMPK-Mediated PPARγ Signaling

Luteolin is a common phytochemical from the flavonoid family with a flavone structure. Studies reported several bioactivities for luteolin and similar flavones. Attenuating the increased adipogenesis of bone marrow cells (hBM-MSCs) has been regarded as a therapeutic target against osteoporotic bone disorders. In the present study, the potential roles of luteolin and its sulfonic acid derivative luteolin-OSO3Na in regulating adipogenic differentiation of hBM-MSCs were investigated. Adipo-induced cells were treated with or without compounds, and their effect on adipogenesis was evaluated by adipogenic marker levels such as lipid accumulation and PPARγ pathway activation. Luteolin hindered the adipogenic lipid accumulation in adipo-induced hBM-MSCs. Immunoblotting and reverse transcription-polymerase chain reaction analysis results indicated that luteolin downregulated PPARγ and downstream factors of C/EBPα and SREBP1c expression which resulted in inhibition of adipogenesis. Luteolin-OSO3Na showed similar effects; however, it was significantly less effective compared to luteolin. Investigating p38, JNK, and ERK MAPKs and AMPK activation indicated that luteolin suppressed the MAPK phosphorylation while stimulating AMPK phosphorylation. On the other hand, luteolin-OSO3Na was not able to notably affect the MAPK and AMPK activation. In conclusion, this study suggested that luteolin inhibited adipogenic differentiation of hBM-MSCs via upregulating AMPK activation. Replacing its 4'-hydroxyl group with sulfonic acid sodium salt diminished its antiadipogenic effect indicating its role in regulating AMPK activation. The general significance is that luteolin is a common phytochemical with various health-beneficial effects. The current study suggested that luteolin may serve as a lead compound for developing antiosteoporotic substances with antiadipogenic properties.

Electroactive Phenolic Contributors and Antioxidant Capacity of Flesh and Peel of 11 Apple Cultivars Measured by Cyclic Voltammetry and HPLC-DAD-MS/MS

In this study, 11 apple cultivars were characterized by their total phenolic content (TPC) and total flavonoid content (TFC) and antioxidant, reducing, and chelating capacity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) test, cyclic voltammetry (CV), and ferric reducing antioxidant power (FRAP) assays; and ferrous ion chelating capacity. The phenolic compounds in flesh and peel were determined by liquid chromatography coupled to mass spectrometry and diode array detector (HPLC-DAD-MS/MS) and their electroactivity by CV. The results showed higher TPC, TFC, and antioxidant capacity by DPPH test in the peels of all apple cultivars as compared to the respective flesh. The peel extracts also showed two-fold higher FRAP values as compared to the flesh extracts. The reducing capacity of the peel and flesh determined by CV measurements confirmed the results achieved by spectrophotometric methods of evaluating antioxidant capacity. There was no significant difference in chelating capacity in the peel and flesh. The HPLC-DAD-MS/MS analysis showed the presence of 11 phenolic compounds in the peel and flesh which varied in antioxidant, reducing, and chelating activity. The order of the phenolic compound content in flesh and peel in Quinte cultivar, which showed the highest antioxidant capacity, was as follows: epicatechin > chlorogenic acid > quercetin 3-arabinoside > quercetin 3-glucoside > cyanidin 3-galactoside > quercetin 3-rhamnoside > catechin > phloridzin > rutin > phloretin = quercetin. CV results were highly correlated with those obtained by spectrophotometry and HPLC-DAD-MS/MS, providing evidence to support the use of cyclic voltammetry as a rapid method to determine the phenolic profile and reducing the power of apple flesh and peel. The association between antioxidant assays and phenolic compound content showed that the highest contribution to the antioxidant capacity of apple peel and flesh was provided by catechin, epicatechin, and cyadinin-3-galactoside, while phloretin, phloridzin, and chlorogenic acid were the main contributors to chelating activity. Results from this study clearly indicate that removing the peel from apples may induce a significant loss of antioxidants.

Special Issue "Flavonoids and Their Disease Prevention and Treatment Potential": Recent Advances and Future Perspectives

In recent years, the interest in flavonoids as dietary bioactives to prevent human diseases, as well as their candidacy as pharmaceutical leads, has exponentially expanded [...].

Effects of Polyphenols on Insulin Resistance

Insulin resistance (IR) is apparent when tissues responsible for clearing glucose from the blood, such as adipose and muscle, do not respond properly to appropriate signals. IR is estimated based on fasting blood glucose and insulin, but some measures also incorporate an oral glucose challenge. Certain (poly)phenols, as supplements or in foods, can improve insulin resistance by several mechanisms including lowering postprandial glucose, modulating glucose transport, affecting insulin signalling pathways, and by protecting against damage to insulin-secreting pancreatic β-cells. As shown by intervention studies on volunteers, the most promising candidates for improving insulin resistance are (-)-epicatechin, (-)-epicatechin-containing foods and anthocyanins. It is possible that quercetin and phenolic acids may also be active, but data from intervention studies are mixed. Longer term and especially dose-response studies on mildly insulin resistant participants are required to establish the extent to which (poly)phenols and (poly)phenol-rich foods may improve insulin resistance in compromised groups.

Insight into Polyphenol and Gut Microbiota Crosstalk: Are Their Metabolites the Key to Understand Protective Effects against Metabolic Disorders?

Lifestyle factors, especially diet and nutrition, are currently regarded as essential avenues to decrease modern-day cardiometabolic disorders (CMD), including obesity, metabolic syndrome, type 2 diabetes, and atherosclerosis. Many groups around the world attribute these trends, at least partially, to bioactive plant polyphenols given their anti-oxidant and anti-inflammatory actions. In fact, polyphenols can prevent or reverse the progression of disease processes through many distinct mechanisms. In particular, the crosstalk between polyphenols and gut microbiota, recently unveiled thanks to DNA-based tools and next generation sequencing, unravelled the central regulatory role of dietary polyphenols and their intestinal micro-ecology metabolites on the host energy metabolism and related illnesses. The objectives of this review are to: (1) provide an understanding of classification, structure, and bioavailability of dietary polyphenols; (2) underline their metabolism by gut microbiota; (3) highlight their prebiotic effects on microflora; (4) discuss the multifaceted roles of their metabolites in CMD while shedding light on the mechanisms of action; and (5) underscore their ability to initiate host epigenetic regulation. In sum, the review clearly documents whether dietary polyphenols and micro-ecology favorably interact to promote multiple physiological functions on human organism.

Bioaccessible Raspberry Extracts Enriched in Ellagitannins and Ellagic Acid Derivatives Have Anti-Neuroinflammatory Properties

Chronic neuroinflammation associated with neurodegenerative disorders has been reported to be prevented by dietary components. Particularly, dietary (poly)phenols have been identified as having anti-inflammatory and neuroprotective actions, and their ingestion is considered a major preventive factor for such disorders. To assess the relation between (poly)phenol classes and their bioactivity, we used five different raspberry genotypes, which were markedly different in their (poly)phenol profiles within a similar matrix. In addition, gastro-intestinal bio-accessible fractions were produced, which simulate the (poly)phenol metabolites that may be absorbed after digestion, and evaluated for anti-inflammatory potential using LPS-stimulated microglia. Interestingly, the fraction from genotype 2J19 enriched in ellagitannins, their degradation products and ellagic acid, attenuated pro-inflammatory markers and mediators CD40, NO, TNF-α, and intracellular superoxide via NF-κB, MAPK and NFAT pathways. Importantly, it also increased the release of the anti-inflammatory cytokine IL-10. These effects contrasted with fractions richer in anthocyanins, suggesting that ellagitannins and its derivatives are major anti-inflammatory (poly)phenols and promising compounds to alleviate neuroinflammation.

Absorption, metabolism, and excretion of orange juice (poly)phenols in humans: The effect of a controlled alcoholic fermentation

The consumption of orange juice provides high concentrations of health-promoting bioactive compounds, the amount of which may increase upon alcoholic fermentation. Although fermentation may offer new prospects for the industry of orange-related products, there is a lack of studies reporting the influence of controlled alcoholic fermentation on the bioavailability of orange juice (poly)phenols in humans. The aim of this study was to evaluate the absorption profile, pharmacokinetic parameters, and urinary excretion of orange juice (poly)phenols in nine volunteers after acute administration of an orange juice and a beverage prepared after controlled alcoholic fermentation of the juice. Plasma and urine samples were analysed through a UHPLC-ESI-MS/MS targeted approach. A total of 24 (poly)phenol metabolites including both flavanone and phenolic acid derivatives were quantified, most of them being recorded only in urine. Phase II conjugates of hesperetin and naringenin were the main metabolites in plasma, while phenolic acids, in particular hydroxybenzoic acids, were the main compounds in urine. (Poly)phenols in both beverages were highly bioavailable (between 46 and 59%) and a notable inter-individual variability was seen. Significant treatment × time interactions were recorded for the sum of flavanones and phenolic acids in plasma, the (poly)phenols in the fermented juice being absorbed faster than after orange juice intake. Nevertheless, despite the food matrix having an impact on the absorption profile of orange juice (poly)phenols, this did not influence the pharmacokinetic parameters and urinary excretion of the (poly)phenol metabolites.

Recommendations for standardizing nomenclature for dietary (poly)phenol catabolites

There is a lack of focus on the protective health effects of phytochemicals in dietary guidelines. Although a number of chemical libraries and databases contain dietary phytochemicals belonging to the plant metabolome, they are not entirely relevant to human health because many constituents are extensively metabolized within the body following ingestion. This is especially apparent for the highly abundant dietary (poly)phenols, for which the situation is compounded by confusion regarding their bioavailability and metabolism, partially because of the variety of nomenclatures and trivial names used to describe compounds arising from microbial catabolism in the gastrointestinal tract. This confusion, which is perpetuated in online chemical/metabolite databases, will hinder future discovery of bioactivities and affect the establishment of future dietary guidelines if steps are not taken to overcome these issues. In order to resolve this situation, a nomenclature system for phenolic catabolites and their human phase II metabolites is proposed in this article and the basis of its format outlined. Previous names used in the literature are cited along with the recommended nomenclature, International Union of Pure and Applied Chemistry terminology, and, where appropriate, Chemical Abstracts Service numbers, InChIKey, and accurate mass.

The Effects of Flavonoids in Cardiovascular Diseases

Flavonoids are metabolites of plants and fungus. Flavonoid research has been paid special attention to in recent times after the observation of their beneficial effects on the cardiovascular system. These favorable effects are exerted by flavonoids mainly due to their antioxidant properties, which result from the ability to decrease the oxidation of low-density lipoproteins, thus improving the lipid profiles. The other positive effect exerted on the cardiovascular system is the ability of flavonoids to produce vasodilation and regulate the apoptotic processes in the endothelium. Researchers suggested that these effects, including their anti-inflammatory function, are consequences of flavonoids' potent antioxidant properties, but recent studies have shown multiple signaling pathways linked to them, thus suggesting that there are more mechanisms involved in the beneficial effect of the flavonoids on the human body. This review aims to present the latest data on the classification of these substances, their main mechanisms of action in the human body, and the beneficial effects on the physiological and pathological status of the cardiovascular system.

Allium Flavonols: Health Benefits, Molecular Targets, and Bioavailability

Allium species are revered worldwide as vegetables, condiments, and spices as well as the therapeutic agents in traditional medicine. The bioactive compounds in alliums mainly include organosulfur compounds, polyphenols, dietary fibers, and saponins. Flavonoids, particularly flavonols from alliums, have been demonstrated to have the antioxidant, anticancer, hypolipidemic, anti-diabetic, cardioprotective, neuroprotective, and antimicrobial activities. However, flavonols are mostly characterized from onions and have not been comprehensively reviewed across different species. This article therefore focuses on flavonol profiles from different Allium species, their health effects, underlying molecular mechanisms, and bioavailability. Intriguingly, the functional health effects of flavonols were mainly ascribed to their antioxidant and anti-inflammatory activities involving a cascade of multiple signaling pathways. Although the Allium-derived flavonols offer tremendous potential in preventing chronic disease risks, in-depth studies are needed to translate their clinical application.