Integrating High-Resolution Mass Spectral Data, Bioassays and Computational Models to Annotate Bioactives in Botanical Extracts: Case Study Analysis of C. asiatica Extract Associates Dicaffeoylquinic Acids with Protection against Amyloid-ß Toxicity.

Rapid screening of botanical extracts for the discovery of bioactive natural products was performed using a fractionation approach in conjunction with flow-injection high-resolution mass spectrometry for obtaining chemical fingerprints of each fraction, enabling the correlation of the relative abundance of molecular features (representing individual phytochemicals) with the read-outs of bioassays. We applied this strategy for discovering and identifying constituents of Centella asiatica (C. asiatica) that protect against Aß cytotoxicity in vitro. C. asiatica has been associated with improving mental health and cognitive function, with potential use in Alzheimer's disease. Human neuroblastoma MC65 cells were exposed to subfractions of an aqueous extract of C. asiatica to evaluate the protective benefit derived from these subfractions against amyloid ß-cytotoxicity. The % viability score of the cells exposed to each subfraction was used in conjunction with the intensity of the molecular features in two computational models, namely Elastic Net and selectivity ratio, to determine the relationship of the peak intensity of molecular features with % viability. Finally, the correlation of mass spectral features with MC65 protection and their abundance in different sub-fractions were visualized using GNPS molecular networking. Both computational methods unequivocally identified dicaffeoylquinic acids as providing strong protection against Aß-toxicity in MC65 cells, in agreement with the protective effects observed for these compounds in previous preclinical model studies.

Gut enterotype-dependent modulation of gut microbiota and their metabolism in response to xanthohumol supplementation in healthy adults.

Xanthohumol (XN), a polyphenol found in the hop plant (Humulus lupulus), has antioxidant, anti-inflammatory, prebiotic, and anti-hyperlipidemic activity. Preclinical evidence suggests the gut microbiome is essential in mediating these bioactivities; however, relatively little is known about XN's impact on human gut microbiota in vivo. We conducted a randomized, triple-blinded, placebo-controlled clinical trial (ClinicalTrials.gov NCT03735420) to determine safety and tolerability of XN in healthy adults. Thirty healthy participants were randomized to 24 mg/day XN or placebo for 8 weeks. As secondary outcomes, quantification of bacterial metabolites and 16S rRNA gene sequencing were utilized to explore the relationships between XN supplementation, gut microbiota, and biomarkers of gut health. Although XN did not significantly change gut microbiota composition, it did re-shape individual taxa in an enterotype-dependent manner. High levels of inter-individual variation in metabolic profiles and bioavailability of XN metabolites were observed. Moreover, reductions in microbiota-derived bile acid metabolism were observed, which were specific to Prevotella and Ruminococcus enterotypes. These results suggest interactions between XN and gut microbiota in healthy adults are highly inter-individualized and potentially indicate that XN elicits effects on gut health in an enterotype-dependent manner.

Dietary (poly)phenols mitigate inflammatory bowel disease: Therapeutic targets, mechanisms of action, and clinical observations.

Inflammatory bowel diseases (IBD), which include Crohn's disease and ulcerative colitis, are a rapidly growing public health concern worldwide. These diseases are heterogeneous at the clinical, immunological, molecular, genetic, and microbial level, but characteristically involve a disrupted immune-microbiome axis. Shortcomings in conventional treatment options warrant the need for novel therapeutic strategies to mitigate these life-long and relapsing disorders of the gastrointestinal tract. Polyphenols, a diverse group of phytochemicals, have gained attention as candidate treatments due to their array of biological effects. Polyphenols exert broad anti-inflammatory and antioxidant effects through the modulation of cellular signaling pathways and transcription factors important in IBD progression. Polyphenols also bidirectionally modulate the gut microbiome, supporting commensals and inhibiting pathogens. One of the primary means by which gut microbiota interface with the host is through the production of metabolites, which are small molecules produced as intermediate or end products of metabolism. There is growing evidence to support that modulation of the gut microbiome by polyphenols restores microbially derived metabolites critical to the maintenance of intestinal homeostasis that are adversely disrupted in IBD. This review aims to define the therapeutic targets of polyphenols that may be important for mitigation of IBD symptoms, as well as to collate evidence for their clinical use from randomized clinical trials.

Xanthohumol microbiome and signature in adults with Crohn's disease (the XMaS trial): a protocol for a phase II triple-masked, placebo-controlled clinical trial.

BACKGROUND: Xanthohumol (XN), a bioactive flavonoid from Humulus lupulus with anti-inflammatory properties, has potential benefits for patients with Crohn's disease (CD), a type of inflammatory bowel disease. We recently completed and published results of a placebo-controlled phase I clinical trial demonstrating the safety and tolerability of 24 mg XN daily for 8 weeks. The present study aims to evaluate the safety and tolerability of the same dose of XN adults with clinically active CD in a placebo-controlled phase II clinical trial. Additional aims will assess the impact of XN on inflammatory biomarkers, platelet function, CD clinical activity, and stool microbial composition. The metabolism of XN will also be evaluated. This article provides a model protocol for consideration in investigations of XN or other natural products in disease states. METHODS: A triple-masked, randomized, placebo-controlled trial will be conducted in adults with clinically active CD. Participants (n ≤ 32) will be randomized to either 24 mg encapsulated XN per day or placebo and followed for 8 weeks. Throughout the trial, participants will be queried for adverse events. Biomarkers of clinical safety, blood and stool markers of inflammation, platelet function, Crohn's Disease Activity Index score, stool microbial composition, and XN metabolite profiles in blood, urine, and stool will be assessed every 2 weeks. DISCUSSION: We describe the protocol for a phase II clinical trial that evaluates the safety and tolerability of XN in adults with active CD, as well as evaluate metabolism and mechanisms that are relevant to CD and other diseases with underlying inflammation and/or gut permeability. The effects of XN on inflammatory biomarkers, platelet function, the microbiota, and multi-omics biomarkers measured in this phase II trial of adults with CD will be compared to the effects of XN in healthy adults in our previous phase I trial. The results of the study will advance the evidence guiding the use of XN in patients with CD. TRIAL REGISTRATION: ClinialTrials.gov NCT04590508. Registered on October 19, 2020.

Phytochemical characterization and bioactivity toward breast cancer cells of unhydrolyzed and acid-hydrolyzed extracts of Fagonia indica.

Phytochemicals from the genus, Fagonia, have been attracting increasing attention due to their potential beneficial effects on human health. Fagonia species contain various types of phytochemicals such as flavonoids, alkaloids, saponins, terpenoids, coumarins and tannins. In this study, we investigated the phytochemical composition of unhydrolyzed and acid-hydrolyzed extracts of Fagonia indica and their bioactivity toward breast cancer MCF-7 cells in vitro. The results revealed that F. indica contains phytochemicals consistent with the reported phytochemical composition of this Fagonia species, with greater amounts of aglycones detected in the hydrolyzed extract. The crude extract of F. indica without acid hydrolysis was found to be ineffective in inhibiting the growth of MCF-7 cells at doses below 1000 µg/mL. However, after acid hydrolysis (to mimic gastro-intestinal hydrolysis), the F. indica extract became growth-inhibitory to MCF-7 cells as low as 10 µg/mL and the cytotoxicity increased with increasing dose and time of treatment. The results suggest that F. indica extracts contain phytochemicals in glycosidic forms whose aglycones are active as anti-proliferative agents toward breast cancer cells in vitro.

Recent Advances in Research on Polyphenols: Effects on Microbiota, Metabolism, and Health.

Polyphenols have attracted huge interest among researchers of various disciplines because of their numerous biological activities, such as antioxidative, antiinflammatory, antiapoptotic, cancer chemopreventive, anticarcinogenic, and antimicrobial properties, and their promising applications in many fields, mainly in the medical, cosmetics, dietary supplement and food industries. In this review, the latest scientific findings in the research on polyphenols interaction with the microbiome and mitochondria, their metabolism and health beneficial effects, their involvement in cognitive diseases and obesity development, as well as some innovations in their analysis, extraction methods, development of cosmetic formulations and functional food are summarized based on the papers presented at the 13th World Congress on Polyphenol Applications. Future implications of polyphenols in disease prevention and their strategic use as prophylactic measures are specifically addressed. Polyphenols may play a key role in our tomorrow´s food and nutrition to prevent many diseases.

Interplay between Cruciferous Vegetables and the Gut Microbiome: A Multi-Omic Approach.

Brassica vegetables contain a multitude of bioactive compounds that prevent and suppress cancer and promote health. Evidence suggests that the gut microbiome may be essential in the production of these compounds; however, the relationship between specific microbes and the abundance of metabolites produced during cruciferous vegetable digestion are still unclear. We utilized an ex vivo human fecal incubation model with in vitro digested broccoli sprouts (Broc), Brussels sprouts (Brus), a combination of the two vegetables (Combo), or a negative control (NC) to investigate microbial metabolites of cruciferous vegetables. We conducted untargeted metabolomics on the fecal cultures by LC-MS/MS and completed 16S rRNA gene sequencing. We identified 72 microbial genera in our samples, 29 of which were significantly differentially abundant between treatment groups. A total of 4499 metabolomic features were found to be significantly different between treatment groups (q ≤ 0.05, fold change > 2). Chemical enrichment analysis revealed 45 classes of compounds to be significantly enriched by brassicas, including long-chain fatty acids, coumaric acids, and peptides. Multi-block PLS-DA and a filtering method were used to identify microbe−metabolite interactions. We identified 373 metabolites from brassica, which had strong relationships with microbes, such as members of the family Clostridiaceae and genus Intestinibacter, that may be microbially derived.

Composition of the Gut Microbiome Influences Production of Sulforaphane-Nitrile and Iberin-Nitrile from Glucosinolates in Broccoli Sprouts.

Isothiocyanates, such as sulforaphane and iberin, derived from glucosinolates (GLS) in cruciferous vegetables, are known to prevent and suppress cancer development. GLS can also be converted by bacteria to biologically inert nitriles, such as sulforaphane-nitrile (SFN-NIT) and iberin-nitrile (IBN-NIT), but the role of the gut microbiome in this process is relatively undescribed and SFN-NIT excretion in humans is unknown. An ex vivo fecal incubation model with in vitro digested broccoli sprouts and 16S sequencing was utilized to explore the role of the gut microbiome in SFN- and IBN-NIT production. SFN-NIT excretion was measured among human subjects following broccoli sprout consumption. The fecal culture model showed high inter-individual variability in nitrile production and identified two sub-populations of microbial communities among the fecal cultures, which coincided with a differing abundance of nitriles. The Clostridiaceae family was associated with high levels, while individuals with a low abundance of nitriles were more enriched with taxa from the Enterobacteriaceae family. High levels of inter-individual variation in urine SFN-NIT levels were also observed, with peak excretion of SFN-NIT at 24 h post broccoli sprout consumption. These results suggest that nitrile production from broccoli, as opposed to isothiocyanates, could be influenced by gut microbiome composition, potentially lowering efficacy of cruciferous vegetable interventions.

Xanthohumol Requires the Intestinal Microbiota to Improve Glucose Metabolism in Diet-Induced Obese Mice.

SCOPE: The polyphenol xanthohumol (XN) improves dysfunctional glucose and lipid metabolism in diet-induced obesity animal models. Because XN changes intestinal microbiota composition, the study hypothesizes that XN requires the microbiota to mediate its benefits. METHODS AND RESULTS: To test the hypothesis, the study feeds conventional and germ-free male Swiss Webster mice either a low-fat diet (LFD, 10% fat derived calories), a high-fat diet (HFD, 60% fat derived calories), or a high-fat diet supplemented with XN at 60 mg kg-1 body weight per day (HXN) for 10 weeks, and measure parameters of glucose and lipid metabolism. In conventional mice, the study discovers XN supplementation decreases plasma insulin concentrations and improves Homeostatic Model Assessment of Insulin Resistance (HOMA-IR). In germ-free mice, XN supplementation fails to improve these outcomes. Fecal sample 16S rRNA gene sequencing analysis suggests XN supplementation changes microbial composition and dramatically alters the predicted functional capacity of the intestinal microbiota. Furthermore, the intestinal microbiota metabolizes XN into bioactive compounds, including dihydroxanthohumol (DXN), an anti-obesogenic compound with improved bioavailability. CONCLUSION: XN requires the intestinal microbiota to mediate its benefits, which involves complex diet-host-microbiota interactions with changes in both microbial composition and functional capacity. The study results warrant future metagenomic studies which will provide insight into complex microbe-microbe interactions and diet-host-microbiota interactions.

Potential use of polyphenols in the battle against COVID-19.

The coronavirus disease 2019 (COVID-19) is a public health emergency of international concern. The rising number of cases of this highly transmissible infection has stressed the urgent need to find a potent drug. Although repurposing of known drugs currently provides an accelerated route to approval, there is no satisfactory treatment. Polyphenols, a major class of bioactive compounds in nature, are known for their antiviral activity and pleiotropic effects. The aim of this review is to assess the effects of polyphenols on COVID-19 drug targets as well as to provide a perspective on the possibility to use polyphenols in the development of natural approaches against this viral disease.

Targeting the Liver-Brain Axis with Hop-Derived Flavonoids Improves Lipid Metabolism and Cognitive Performance in Mice.

SCOPE: Sphingolipids including ceramides are implicated in the pathogenesis of obesity and insulin resistance. Correspondingly, inhibition of pro-inflammatory and neurotoxic ceramide accumulation prevents obesity-mediated insulin resistance and cognitive impairment. Increasing evidence suggests the farnesoid X receptor (FXR) is involved in ceramide metabolism, as bile acid-FXR crosstalk controls ceramide levels along the gut-liver axis. The authors previously reported that FXR agonist xanthohumol (XN), the principal prenylated flavonoid in hops (Humulus lupulus), and its hydrogenated derivatives, α,ß-dihydroxanthohumol (DXN), and tetrahydroxanthohumol (TXN), ameliorated obesity-mediated insulin resistance, and cognitive impairment in mice fed a high-fat diet. METHODS AND RESULTS: To better understand how the flavonoids improve both, lipid and bile acid profiles in the liver are analyzed, sphingolipid relative abundance in the hippocampus is measured, and linked them to metabolic and neurocognitive performance. XN, DXN, and TXN (30 mg kg-1 BW per day) decrease ceramide content in liver and hippocampus; the latter is linked to improvements in spatial learning and memory. In addition, XN, DXN, and TXN decrease hepatic cholesterol content by enhancing de novo synthesis of bile acids. CONCLUSION: These observations suggest that XN, DXN, and TXN may alleviate obesity-induced metabolic and neurocognitive impairments by targeting the liver-brain axis.

Antiproliferative and Cytotoxic Activity of Xanthohumol and Its Non-Estrogenic Derivatives in Colon and Hepatocellular Carcinoma Cell Lines.

Xanthohumol (XN), a prenylated flavonoid found in hops, inhibits growth in a variety of cancer cell lines; however, its use raises concerns as gut microbiota and the host's hepatic cytochrome P450 enzymes metabolize it into the most potent phytoestrogen known, 8-prenylnaringenin (8-PN). The XN derivatives dihydroxanthohumol (DXN) and tetrahydroxanthohumol (TXN) are not metabolized into 8-PN and they show higher tissue concentrations in vivo compared with XN when orally administered to mice at the same dose. Here we show that DXN and TXN possess improved anti-proliferative activity compared with XN in two colon (HCT116, HT29) and two hepatocellular (HepG2, Huh7) carcinoma cell lines, as indicated by their respective IC50 values. Furthermore, XN, DXN, and TXN induce extensive apoptosis in all these carcinoma cell lines. Finally, TXN induces G0/G1 cell cycle arrest in the colon carcinoma cell line HT29. Our findings suggest that DXN and TXN could show promise as therapeutic agents against colorectal and liver cancer in preclinical studies without the drawback of metabolism into a phytoestrogen.

Reductive Metabolism of Xanthohumol and 8-Prenylnaringenin by the Intestinal Bacterium Eubacterium ramulus.

SCOPE: The intestinal microbiota transforms a wide range of available substrates, including polyphenols. Microbial catabolites of polyphenols can contribute in significant ways to the health-promoting properties of their parent polyphenols. This work aims to identify intestinal metabolites of xanthohumol (XN), a prenylated flavonoid found in hops (Humulus lupulus) and beer, as well as to identify pathways of metabolism of XN in the gut. METHODS AND RESULTS: To investigate intestinal metabolism, XN and related prenylated flavonoids, isoxanthohumol (IX), and 8-prenylnaringenin (8PN) were added to growing cultures of intestinal bacteria, Eubacterium ramulus and E. limosum. Liquid chromatography coupled with mass spectrometry was used to identify metabolites of the flavonoids from the cultures. The metabolic capacity of E. limosum appears to be limited to O-demethylation. Evidence from the study indicates that E. ramulus hydrogenates XN to form α,ß-dihydroxanthohumol (DXN) and metabolizes the potent phytoestrogen 8PN into the chalcones, O-desmethylxanthohumol (DMX) and O-desmethyl-α,ß-dihydroxanthohumol (DDXN). CONCLUSION: Microbial metabolism is likely to affect both activity and toxicity of XN and derivatives. This study along with others highlights that attention should be focused on metabolites, in particular, products of intestinal microbial metabolism.

Sulforaphane absorption and histone deacetylase activity following single dosing of broccoli sprout supplement in normal dogs.

The role of epigenetic alterations during cancer has gained increasing attention and has resulted in a paradigm shift in our understanding of mechanisms leading to cancer susceptibility. Sulforaphane (SFN) is a naturally occurring isothiocyanate derived from the precursor glucosinolate, glucoraphanin (GFN), which is found in cruciferous vegetables such as broccoli. Sulforaphane has been shown to suppress tumour growth by several mechanisms including inhibiting histone deacetylases. The objective of this study was to provide a detailed analysis of sulforaphane absorption following a single oral dose of a broccoli sprout supplement in normal dogs. A single dose of broccoli sprout supplement (with active myrosinase) was orally administered to 10 healthy adult dogs. Blood and urine samples were collected prior to dosing, and at various time points post-dosing. Plasma total SFN metabolite levels peaked at 4 h post-consumption and were cleared by 24 h post-consumption. Urinary SFN metabolites peaked at 4 h post-consumption, and remained detectable at 24 and 48 h post-supplement consumption. A trend for decrease in histone deacetylase activity was observed at 1 h post-consumption and a significant decrease was observed at 24 h post-consumption. The data presented herein indicate that oral SFN is absorbed in dogs, SFN metabolites are detectable in plasma and urine post-dosing, and SFN and its metabolites have some effect on histone deacetylase activity following a single dose.

Isolation and Identification of Tyrosinase-Inhibitory and Copper-Chelating Peptides from Hydrolyzed Rice-Bran-Derived Albumin.

Rice-bran albumin (RBAlb), which shows higher tyrosinase-inhibitory activity than other protein fractions, was hydrolyzed with papain to improve the bioactivity. The obtained RBAlb hydrolysate (RBAlbH) was separated into 11 peptide fractions by RP-HPLC. Tyrosinase inhibition and copper chelation activities decreased with increasing retention times of the peptide fractions. RBAlbH fraction 1, which exhibited the greatest activity, contained 13 peptides whose sequences were determined by using LC-MS/MS. Most of the peptide sequences contained features of previously reported tyrosinase-inhibitory and metal-chelating peptides, especially peptide SSEYYGGEGSSSEQGYYGEG. RBAlbH fraction 1 showed more effective tyrosinase inhibition (IC50 = 1.31 mg/mL) than citric acid (IC50 = 9.38 mg/mL), but it was less effective than ascorbic acid (IC50 = 0.03 mg/mL, P ≤ 0.05). It showed copper-chelating activity (IC50 = 0.62 mg/mL) stronger than that of EDTA (IC50 = 1.06 mg/mL, P ≤ 0.05). These results suggest that RBAlbH has potential as a natural tyrosinase inhibitor and copper chelator for application in the food and cosmetic industries.

Photoprotective Properties of Isothiocyanate and Nitrile Glucosinolate Derivatives From Meadowfoam (Limnanthes alba) Against UVB Irradiation in Human Skin Equivalent.

Exposure to ultraviolet B (UVB) irradiation of the skin leads to numerous dermatological concerns including skin cancer and accelerated aging. Natural product glucosinolate derivatives, like sulforaphane, have been shown to exhibit chemopreventive and photoprotective properties. In this study, we examined meadowfoam (Limnanthes alba) glucosinolate derivatives, 3-methoxybenzyl isothiocyanate (MBITC) and 3-methoxyphenyl acetonitrile (MPACN), for their activity in protecting against the consequences of UV exposure. To that end, we have exposed human primary epidermal keratinocytes (HPEKs) and 3D human skin reconstructed in vitro (EpiDermTM FT-400) to UVB insult and investigated whether MBITC and MPACN treatment ameliorated the harmful effects of UVB damage. Activity was determined by the compounds' efficacy in counteracting UVB-induced DNA damage, matrix-metalloproteinase (MMP) expression, and proliferation. We found that in monolayer cultures of HPEK, MBITC and MPACN did not protect against a UVB-induced loss in proliferation and MBITC itself inhibited cell proliferation. However, in human reconstructed skin-equivalents, MBITC and MPACN decrease epidermal cyclobutane pyrimidine dimers (CPDs) and significantly reduce total phosphorylated γH2A.X levels. Both MBITC and MPACN inhibit UVB-induced MMP-1 and MMP-3 expression indicating their role to prevent photoaging. Both compounds, and MPACN in particular, showed activity against UVB-induced proliferation as indicated by fewer epidermal PCNA+ cells and prevented UVB-induced hyperplasia as determined by a reduction in reconstructed skin epidermal thickness (ET). These data demonstrate that MBITC and MPACN exhibit promising anti-photocarcinogenic and anti-photoaging properties in the skin microenvironment and could be used for therapeutic interventions.

Untargeted Metabolomic Screen Reveals Changes in Human Plasma Metabolite Profiles Following Consumption of Fresh Broccoli Sprouts.

SCOPE: Several lines of evidence suggest that the consumption of cruciferous vegetables is beneficial to human health. Yet, underlying mechanisms and key molecular targets that are involved with achieving these benefits in humans are still not fully understood. To accelerate this research, we conduct a human study to identify potential molecular targets of crucifers for further study. This study aims to characterize plasma metabolite profiles in humans before and after consuming fresh broccoli sprouts (a rich dietary source of bioactive sulforaphane). METHODS AND RESULTS: Ten healthy adults consume fresh broccoli sprouts (containing 200 µmol sulforaphane equivalents) at time 0 and provide blood samples at 0, 3, 6, 12, 24, and 48 h. An untargeted metabolomics screen reveals that levels of several plasma metabolites are significantly different before and after sprout intake, including fatty acids (14:0, 14:1, 16:0, 16:1, 18:0, and 18:1), glutathione, glutamine, cysteine, dehydroepiandrosterone, and deoxyuridine monophosphate. Evaluation of all time points is conducted using paired t-test (R software) and repeated measures analysis of variance for a within-subject design (Progenesis QI). CONCLUSION: This investigation identifies several potential molecular targets of crucifers that may aid in studying established and emerging health benefits of consuming cruciferous vegetables and related bioactive compounds.

Non-estrogenic Xanthohumol Derivatives Mitigate Insulin Resistance and Cognitive Impairment in High-Fat Diet-induced Obese Mice.

Xanthohumol (XN), a prenylated flavonoid from hops, improves dysfunctional glucose and lipid metabolism in animal models of metabolic syndrome (MetS). However, its metabolic transformation into the estrogenic metabolite, 8-prenylnaringenin (8-PN), poses a potential health concern for its use in humans. To address this concern, we evaluated two hydrogenated derivatives, α,ß-dihydro-XN (DXN) and tetrahydro-XN (TXN), which showed negligible affinity for estrogen receptors α and ß, and which cannot be metabolically converted into 8-PN. We compared their effects to those of XN by feeding C57BL/6J mice a high-fat diet (HFD) containing XN, DXN, or TXN for 13 weeks. DXN and TXN were present at higher concentrations than XN in plasma, liver and muscle. Mice administered XN, DXN or TXN showed improvements of impaired glucose tolerance compared to the controls. DXN and TXN treatment resulted in a decrease of HOMA-IR and plasma leptin. C2C12 embryonic muscle cells treated with DXN or TXN exhibited higher rates of uncoupled mitochondrial respiration compared to XN and the control. Finally, XN, DXN, or TXN treatment ameliorated HFD-induced deficits in spatial learning and memory. Taken together, DXN and TXN could ameliorate the neurocognitive-metabolic impairments associated with HFD-induced obesity without risk of liver injury and adverse estrogenic effects.

Rice Protein Matrix Enhances Circulating Levels of Xanthohumol Following Acute Oral Intake of Spent Hops in Humans.

SCOPE: Xanthohumol (XN), a prenylated flavonoid found in hops, exhibits anti-inflammatory and antioxidant properties. However, poor bioavailability may limit therapeutic applications. As food components are known to modulate polyphenol absorption, the objective is to determine whether a protein matrix could enhance the bioavailability of XN post oral consumption in humans. METHODS AND RESULTS: This is a randomized, double-blind, crossover study in healthy participants (n = 6) evaluating XN and its major metabolites (isoxanthohumol [IX], 6- and 8-prenylnaringenin [6-PN, 8-PN]) for 6 h following consumption of 12.4 mg of XN delivered via a spent hops-rice protein matrix preparation or a control spent hops preparation. Plasma XN and metabolites are measured by LC-MS/MS. Cmax , Tmax , and area-under-the-curve (AUC) values were determined. Circulating XN and metabolite response to each treatment was not bioequivalent. Plasma concentrations of XN and XN + metabolites (AUC) are greater with consumption of the spent hops-rice protein matrix preparation. CONCLUSION: Compared to a standard spent hops powder, a protein-rich spent hops matrix demonstrates enhanced plasma levels of XN and metabolites following acute oral intake.

Mitochondria-Centric Review of Polyphenol Bioactivity in Cancer Models.

SIGNIFICANCE: Humans are exposed daily to polyphenols in milligram-to-gram amounts through dietary consumption of fruits and vegetables. Polyphenols are also available as components of dietary supplements for improving general health. Although polyphenols are often advertised as antioxidants to explain health benefits, experimental evidence shows that their beneficial cancer preventing and controlling properties are more likely due to stimulation of pro-oxidant and proapoptotic pathways. Recent Advances: The understanding of the biological differences between cancer and normal cell, and especially the role that mitochondria play in carcinogenesis, has greatly advanced in recent years. These advances have resulted in a wealth of new information on polyphenol bioactivity in cell culture and animal models of cancer. Polyphenols appear to target oxidative phosphorylation and regulation of the mitochondrial membrane potential (MMP), glycolysis, pro-oxidant pathways, and antioxidant (adaptive) stress responses with greater selectivity in tumorigenic cells. CRITICAL ISSUES: The ability of polyphenols to dissipate the MMP (Δψm) by a protonophore mechanism has been known for more than 50 years. However, researchers focus primarily on the downstream molecular effects of Δψm dissipation and mitochondrial uncoupling. We argue that the physicochemical properties of polyphenols are responsible for their anticancer properties by virtue of their protonophoric and pro-oxidant properties rather than their specific effects on downstream molecular targets. FUTURE DIRECTIONS: Polyphenol-induced dissipation of Δψm is a physicochemical process that cancer cells cannot develop resistance against by gene mutation. Therefore, polyphenols should receive more attention as agents for cotherapy with cancer drugs to gain synergistic activity. Antioxid. Redox Signal.