In vivo study of the bioavailability and metabolic profile of (poly)phenols after sous-vide artichoke consumption

Exploring and disentangling the production of potentially bioactive phenolic catabolites from dietary (poly)phenols, phenylalanine, tyrosine and catecholamines

Following ingestion of fruits, vegetables and derived products, (poly)phenols that are not absorbed in the upper gastrointestinal tract pass to the colon, where they undergo microbiota-mediated ring fission resulting in the production of a diversity of low molecular weight phenolic catabolites, which appear in the circulatory system and are excreted in urine along with their phase II metabolites. There is increasing interest in these catabolites because of their potential bioactivity and their use as biomarkers of (poly)phenol intake. Investigating the fate of dietary (poly)phenolics in the colon has become confounded as a result of the recent realisation that many of the phenolics appearing in biofluids can also be derived from the aromatic amino acids, l-phenylalanine and l-tyrosine, and to a lesser extent catecholamines, in reactions that can be catalysed by both colonic microbiota and endogenous mammalian enzymes. The available evidence, albeit currently rather limited, indicates that substantial amounts of phenolic catabolites originate from phenylalanine and tyrosine, while somewhat smaller quantities are produced from dietary (poly)phenols. This review outlines information on this topic and assesses procedures that can be used to help distinguish between phenolics originating from dietary (poly)phenols, the two aromatic amino acids and catecholamines.

Factors driving the inter-individual variability in the metabolism and bioavailability of (poly)phenolic metabolites: A systematic review of human studies

This systematic review provides an overview of the available evidence on the inter-individual variability (IIV) in the absorption, distribution, metabolism, and excretion (ADME) of phenolic metabolites and its determinants. Human studies were included investigating the metabolism and bioavailability of (poly)phenols and reporting IIV. One hundred fifty-three studies met the inclusion criteria. Inter-individual differences were mainly related to gut microbiota composition and activity but also to genetic polymorphisms, age, sex, ethnicity, BMI, (patho)physiological status, and physical activity, depending on the (poly)phenol sub-class considered. Most of the IIV has been poorly characterised. Two major types of IIV were observed. One resulted in metabolite gradients that can be further classified into high and low excretors, as seen for all flavonoids, phenolic acids, prenylflavonoids, alkylresorcinols, and hydroxytyrosol. The other type of IIV is based on clusters of individuals defined by qualitative differences (producers vs. non-producers), as for ellagitannins (urolithins), isoflavones (equol and O-DMA), resveratrol (lunularin), and preliminarily for avenanthramides (dihydro-avenanthramides), or by quali-quantitative metabotypes characterized by different proportions of specific metabolites, as for flavan-3-ols, flavanones, and even isoflavones. Future works are needed to shed light on current open issues limiting our understanding of this phenomenon that likely conditions the health effects of dietary (poly)phenols.

Effects of Matrix Structure on Protein Digestibility and Antioxidant Property of Different Soybean Curds During In Vitro Digestion

This study compared the three most common types of tofu (soybean curd), which were prepared by using magnesium chloride (MgCl2 tofu), calcium sulfate (CaSO4 tofu), and glucono-δ-lactone (GDL tofu) coagulants. The results showed that GDL tofu had a higher water holding capacity than MgCl2 tofu and CaSO4 tofu, which was attributed to its high surface hydrophobicity and disulfide bond content. GDL tofu possessed the lowest firmness, gumminess, and chewiness, along with a uniform network structure and a thin protein matrix. In contrast, MgCl2 tofu exhibited an inhomogeneous network structure with a thick protein matrix. Combining the results of protein hydrolysis degree, SDS-PAGE, and free amino acids during in vitro digestion, it was indicated that the degree of protein digestion in GDL tofu was the highest. After intestinal digestion, GDL tofu had the highest total phenolic content, ferric reducing antioxidant power, and DPPH value. These results demonstrated the superior protein digestibility and antioxidant property of GDL tofu during in vitro digestion due to its structural characteristics that facilitate enzyme diffusion in the matrix. The findings offer insight into the protein digestibility and antioxidant properties of different types of tofu during digestion from structural characteristic perspective and valuable reference information for consumer dietary nutrition.

Bioactive compounds in coffee and their role in lowering the risk of major public health consequences: A review

This article addresses the bioactive components in coffee aroma, their metabolism, and the mechanism of action in lowering the risk of various potential health problems. The main bioactive components involved in the perceived aroma of coffee and its related health benefits are caffeine, chlorogenic acid (CGA), trigonelline, diterpenes, and melanoids. These compounds are involved in various physiological activities. Caffeine has been shown to have anticancer properties, as well as the ability to prevent the onset and progression of hepatocellular carcinoma and to be anti-inflammatory. CGA exhibits antioxidant action and is implicated in gut health, neurodegenerative disease protection, type 2 diabetes, and cardiovascular disease prevention. Furthermore, together with diterpenes, CGA has been linked to anticancer activity. Trigonelline, on the other side, has been found to lower oxidative stress by increasing antioxidant enzyme activity and scavenging reactive oxygen species. It also prevents the formation of kidney stones. Diterpenes and melanoids possess anti-inflammatory and antioxidant properties, respectively. Consuming three to four cups of filtered coffee per day, depending on an individual's physiological condition and health status, has been linked to a lower risk of several degenerative diseases. Despite their health benefits, excessive coffee intake above the recommended daily dosage, calcium and vitamin D deficiency, and unfiltered coffee consumption all increase the risk of potential health concerns. In conclusion, moderate coffee consumption lowers the risk of different noncommunicable diseases.

A critical examination of human data for the biological activity of quercetin and its phase-2 conjugates

This critical review examines evidence for beneficial effects of quercetin phase-2 conjugates from clinical intervention studies, volunteer feeding trials, and in vitro work. Plasma concentrations of quercetin-3-O-glucuronide (Q3G) and 3'-methylquercetin-3-O-glucuronide (3'MQ3G) after supplementation may produce beneficial effects in macrophages and endothelial cells, respectively, especially if endogenous deglucuronidation occurs, and lower blood uric acid concentration via quercetin-3'-O-sulfate (Q3'S). Unsupplemented diets produce much lower concentrations (<50 nmol/l) rarely investigated in vitro. At 10 nmol/l, Q3'S and Q3G stimulate or suppress, respectively, angiogenesis in endothelial cells. Statistically significant effects have been reported at 100 nmol/l in breast cancer cells (Q3G), primary neuron cultures (Q3G), lymphocytes (Q3G and3'MQ3G) and HUVECs (QG/QS mixture), but it is unclear whether these translate to a health benefit in vivo. More sensitive and more precise methods to measure clinically significant endpoints are required before a conclusion can be drawn regarding effects at normal dietary concentrations. Future requirements include better understanding of inter-individual and temporal variation in plasma quercetin phase-2 conjugates, their mechanisms of action including deglucuronidation and desulfation both in vitro and in vivo, tissue accumulation and washout, as well as potential for synergy or antagonism with other quercetin metabolites and metabolites of other dietary phytochemicals.

Characterization of the metabolic fate of sinapic acid in rats

Sinapic acid (SA) is ubiquitously distributed in the plant kingdom as a free organic acid and more frequently as a biosynthetic pioneer for SA derivatives, e.g., SA esters. Broad biological and pharmacological activities have been disclosed for SA. Because of the metabolism lability property, metabolites instead of the parent compound should be the primary forms after oral treatment of SA, and those metabolites should also be rapidly observed from SA following administration of SA derivative. Hence, the metabolites might provide a primary contribution to the pharmacological properties of SA; however, the metabolite profile remains unclear. Here, our efforts were devoted to addressing this issue through deploying online energy-resolved mass spectrometry (ER-MS) to accomplish isomer identification which is the key issue hindering metabolite identification, notably those conjugated metabolites. After recording breakdown graphs of concerned fragment ions with online ER-MS, the positive correlations between optimal collision energy (OCE) and bond dissociation energy (BDE) were applied to assign candidate structures to isomeric signals. Moreover, in vitro metabolism with liver cellular subfractions, UV-triggered cis-/trans-configuration transformation, and wet-chemistry hydrogenation were carried out to justify the structures. As a result, sixteen metabolites (M1-M16) were found and confirmatively identified in rat plasma and urine following SA administration, and sulfation, glucuronidation, demethylation, reduction, and dihydroxylation served as the primary metabolic channels. Noteworthily, greater distribution occurred for sulfation and glucuronidation products while inferior distributions were observed for phase I metabolites, and the half-life (T1/2) of most metabolites was greater than that of SA. This study provides a comprehensive insight into the metabolic fate of SA. More importantly, the fortification of online ER-MS and quantum structure calculation to the conventional LC-MS program is eligible to achieve unambiguous identification of isomeric metabolites.

Quercetins, Chlorogenic Acids and Their Colon Metabolites Inhibit Colon Cancer Cell Proliferation at Physiologically Relevant Concentrations

Several studies have suggested that a phenolic-rich diet may be protective against colon cancer. Most phenolic compounds are not absorbed in the small intestine and reach the colon where they are metabolized by gut microbiota in simple phenolic acids. In this study, the anti-proliferative activity of quercetins, chlorogenic acids, their colon metabolites and mixtures of parent compounds/metabolites was assessed by using two colon cancer cell lines (Caco-2 and SW480) at physiologically relevant concentrations. Chlorogenic acids, quercetin and the metabolite 3-(3',4'-dihydroxyphenyl)acetic acid exerted remarkable anti-proliferative activity against Caco-2, whereas quercetin derivatives and metabolites were the most active against SW480. Tested compounds arrested the cell cycle at the S phase in both the cell lines. The mixtures of parent compounds/metabolites, which mimic the colon human metabotypes that slowly or rapidly metabolize the parent compounds, similarly inhibited cell growth. SW480 cells metabolized parent phenolic compounds more rapidly and extensively than Caco-2, whereas colon metabolites were more stable. These results suggest that dietary phenolic compounds exert an anti-proliferative effect against human colon cancer cells that can be further sustained by the colon metabolites. Therefore, gut microbiota metabolism of phenolic compounds may be of paramount importance in explaining the protective effect of phenolic-rich foods against colon cancer.

Interplay between Phytochemicals and the Colonic Microbiota

Phytochemicals are natural compounds found in food ingredients with a variety of health-promoting properties. Phytochemicals improve host health through their direct systematic absorption into the circulation and modulation of the gut microbiota. The gut microbiota increases the bioactivity of phytochemicals and is a symbiotic partner whose composition and/or diversity is altered by phytochemicals and affects host health. In this review, the interactions of phytochemicals with the gut microbiota and their impact on human diseases are reviewed. We describe the role of intestinal microbial metabolites, including short-chain fatty acids, amino acid derivatives, and vitamins, from a therapeutic perspective. Next, phytochemical metabolites produced by the gut microbiota and the therapeutic effect of some selected metabolites are reviewed. Many phytochemicals are degraded by enzymes unique to the gut microbiota and act as signaling molecules in antioxidant, anti-inflammatory, anticancer, and metabolic pathways. Phytochemicals can ameliorate diseases by altering the composition and/or diversity of the gut microbiota, and they increase the abundance of some gut microbiota that produce beneficial substances. We also discuss the importance of investigating the interactions between phytochemicals and gut microbiota in controlled human studies.

Hairy Root Cultures as a Source of Phenolic Antioxidants: Simple Phenolics, Phenolic Acids, Phenylethanoids, and Hydroxycinnamates

Plant-derived antioxidants are intrinsic components of human diet and factors implicated in tolerance mechanisms against environmental stresses in both plants and humans. They are being used as food preservatives and additives or ingredients of cosmetics. For nearly forty years, Rhizobium rhizogenes-transformed roots (hairy roots) have been studied in respect to their usability as producers of plant specialized metabolites of different, primarily medical applications. Moreover, the hairy root cultures have proven their value as a tool in crop plant improvement and in plant secondary metabolism investigations. Though cultivated plants remain a major source of plant polyphenolics of economic importance, the decline in biodiversity caused by climate changes and overexploitation of natural resources may increase the interest in hairy roots as a productive and renewable source of biologically active compounds. The present review examines hairy roots as efficient producers of simple phenolics, phenylethanoids, and hydroxycinnamates of plant origin and summarizes efforts to maximize the product yield. Attempts to use Rhizobium rhizogenes-mediated genetic transformation for inducing enhanced production of the plant phenolics/polyphenolics in crop plants are also mentioned.

Metabolism of phenolics in coffee and plant-based foods by canonical pathways: an assessment of the role of fatty acid β-oxidation to generate biologically-active and -inactive intermediates

ω-Phenyl-alkenoic acids are abundant in coffee, fruits, and vegetables. Along with ω-phenyl-alkanoic acids, they are produced from numerous dietary (poly)phenols and aromatic amino acids in vivo. This review addresses how phenyl-ring substitution and flux modulates their gut microbiota and endogenous β-oxidation. 3',5'-Dihydroxy-derivatives (from alkyl-resorcinols, flavanols, proanthocyanidins), and 4'-hydroxy-phenolic acids (from tyrosine, p-coumaric acid, naringenin) are β-oxidation substrates yielding benzoic acids. In contrast, 3',4',5'-tri-substituted-derivatives, 3',4'-dihydroxy-derivatives and 3'-methoxy-4'-hydroxy-derivatives (from coffee, tea, cereals, many fruits and vegetables) are poor β-oxidation substrates with metabolism diverted via gut microbiota dehydroxylation, phenylvalerolactone formation and phase-2 conjugation, possibly a strategy to conserve limited pools of coenzyme A. 4'-Methoxy-derivatives (citrus fruits) or 3',4'-dimethoxy-derivatives (coffee) are susceptible to hepatic "reverse" hydrogenation suggesting incompatibility with enoyl-CoA-hydratase. Gut microbiota-produced 3'-hydroxy-4'-methoxy-derivatives (citrus fruits) and 3'-hydroxy-derivatives (numerous (poly)phenols) are excreted as the phenyl-hydracrylic acid β-oxidation intermediate suggesting incompatibility with hydroxy-acyl-CoA dehydrogenase, albeit with considerable inter-individual variation. Further investigation is required to explain inter-individual variation, factors determining the amino acid to which C6-C3 and C6-C1 metabolites are conjugated, the precise role(s) of l-carnitine, whether glycine might be limiting, and whether phenolic acid-modulation of β-oxidation explains how phenolic acids affect key metabolic conditions, such as fatty liver, carbohydrate metabolism and insulin resistance.

All Polyphenols Are Not Created Equal: Exploring the Diversity of Phenolic Metabolites

Dietary intake of plant polyphenols is significant, and many of them enter a human body as a highly diverse pool of ring-fission phenolic metabolites arising from digestion and microbial catabolism of the parental structures. Difficulty in designing the uniform intervention studies and limited tools calibrated to detect and quantify the inherent complexity of phenolic metabolites hindered efforts to establish and validate protective health effects of these molecules. Here, we highlight the recent findings that describe novel complex downstream metabolite profiles with a particular focus on dihydrophenolic (phenylpropanoic) acids of microbial origin, ingested and phase II-transformed methylated phenolic metabolites (methylated sinks), and small phenolic metabolites derived from the breakdown of different classes of flavonoids, stilbenoids, and tannins. There is a critical need for precise identification of the individual phenolic metabolite signatures originating from different polyphenol groups to enable future translation of these findings into break-through nutritional interventions and dietary guidelines.

Stability of Chlorogenic Acid from Artemisiae Scopariae Herba Enhanced by Natural Deep Eutectic Solvents as Green and Biodegradable Extraction Media

A green and inexpensive natural deep eutectic solvent (NADES) was screened and integrated with an ultrasonic technique for extracting chlorogenic acid (CGA) from artemisiae scopariae herba. Response surface methodology was employed to investigate significant factors and optimize their influence. Proline-malic acid exhibited an excellent extraction capacity with a yield of 28.23 mg/g under the optimal conditions of water content of 15% (wt), solid-liquid ratio of 1.0/10 (g/mL), ultrasonic power of 300 W, and extraction time of 25 min. Simultaneously, the stability and antioxidant activity analysis exhibited a better performance of CGA in NADES than that in water and ethanol. The hydrogen-bonding interaction between CGA and natural deep eutectic molecules enhanced the stability and meanwhile protected the antioxidant activity of CGA.

Based on Multi-Activity Integrated Strategy to Screening, Characterization and Quantification of Bioactive Compounds from Red Wine

According to French Paradox, red wine was famous for the potential effects on coronary heart disease (CHD), but the specific compounds against CHD were unclear. Therefore, screening and characterization of bioactive compounds from red wine was extremely necessary. In this paper, the multi-activity integrated strategy was developed and validated to screen, identify and quantify active compounds from red wine by using ultra high performance liquid chromatography-fraction collector (UHPLC-FC), ultra fast liquid chromatography-quadrupole-time-of-flight/mass spectrometry (UFLC-Q-TOF/MS) and bioactive analysis. UHPLC-FC was employed to separate and collect the components from red wine, which was further identified by UFLC-Q-TOF/MS to acquire their structural information. Furthermore, the active fractions were tested for antioxidant activity, inhibitory activity against thrombin and lipase activities in vitro by the activity screening kit. As the results, there were 37 fractions had antioxidant activity, 22 fractions had thrombin inhibitory activity and 28 fractions had lipase inhibitory activity. Finally, 77 active components from red wine were screened and 12 ingredients out of them were selected for quantification based on the integration of multi-activity. Collectively, the multi-activity integrated strategy was helpful for the rapid and effective discovery of bioactive components, which provided reference for exploring the health care function of food.