Dietary phenolics: chemistry, bioavailability and effects on health.
TL;DR: This review summarizes the chemistry, biosynthesis and occurrence of the compounds involved, namely the C6-C3-C6 flavonoids-anthocyanins, dihydrochalcones, Flavan-3-ols, flavanones, flavones, Flavonols and isoflavones, and the mechanisms underlying these processes are discussed.
About: This article is published in Natural Product Reports.The article was published on 2009-07-22. It has received 1728 citations till now.
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TL;DR: It is concluded that better performed in vivo intervention and in vitro mechanistic studies are needed to fully understand how (poly)phenol molecules interact with human physiological and pathological processes.
Abstract: Human intervention trials have provided evidence for protective effects of various (poly)phenol-rich foods against chronic disease, including cardiovascular disease, neurodegeneration, and cancer. While there are considerable data suggesting benefits of (poly)phenol intake, conclusions regarding their preventive potential remain unresolved due to several limitations in existing studies. Bioactivity investigations using cell lines have made an extensive use of both (poly)phenolic aglycones and sugar conjugates, these being the typical forms that exist in planta, at concentrations in the low-μM-to-mM range. However, after ingestion, dietary (poly)phenolics appear in the circulatory system not as the parent compounds, but as phase II metabolites, and their presence in plasma after dietary intake rarely exceeds nM concentrations. Substantial quantities of both the parent compounds and their metabolites pass to the colon where they are degraded by the action of the local microbiota, giving rise principally to small phenolic acid and aromatic catabolites that are absorbed into the circulatory system. This comprehensive review describes the different groups of compounds that have been reported to be involved in human nutrition, their fate in the body as they pass through the gastrointestinal tract and are absorbed into the circulatory system, the evidence of their impact on human chronic diseases, and the possible mechanisms of action through which (poly)phenol metabolites and catabolites may exert these protective actions. It is concluded that better performed in vivo intervention and in vitro mechanistic studies are needed to fully understand how these molecules interact with human physiological and pathological processes.
1,968 citations
Cites background from "Dietary phenolics: chemistry, bioav..."
...In a recent human cocoa feeding study in which (i) authentic flavan-3-ol metabolites were available to assist analysis, and (ii) the ( - )-epicatechin intake was 6.2 mmol/kg body weight, the following metabolites were identified in plasma with a Tmax of 2 h: ( - )-epicatechin-3¢-O-glucuronide (Cmax, 589 – 85 nM), 4¢-O-methyl-( - )-epicatechin-7-O-glucuronide (Cmax, *20 nM), ( - )-epicatechin-3¢-O-sulfate (Cmax, 331 – 26 nM), ( - )-epicatechin-5-O-sulfate (Cmax, 37 – 3 nM), and ( - )-epicatechin-7-O-sulfate (Cmax, 12 – 1 nM) (Fig....
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...Metabolites of both [13C]isoflavones began appearing in plasma within 1 h of feeding, and sub–lM Cmax values were associated with Tmax times of 5.5 h for genistein and 7.4 h for daidzein metabolites, and T½ times of *7.7 h....
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...The main component that accumulated was an (epi)gallocatechin-O-glucuronide, with a Cmax of 126 nM and a Tmax of 2.2 h, whereas an (epi)catechin-O-glucuronide attained a Cmax of 29 nM with a 1.7 h Tmax....
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...It is possible that the kidneys are unable to remove ( - )-epigallocatechin-3-O-gallate from the bloodstream, but if this is the case, there must be other mechanisms that result in its rapid decline after reaching Cmax....
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...However, as outlined in previous sections of this review, after ingestion, with few exceptions, dietary (poly)phenolics appear in the circulatory system not as the parent compounds, but as glucuronide, methyl, and sulfate metabolites, and their presence in plasma after normal dietary intake rarely exceeds nM concentrations, even at Cmax (93, 109)....
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TL;DR: This Review gives answers from a chemical perspective, summarizes the state of the art, and highlights the most significant advances in the field of polyphenol research.
Abstract: Eating five servings of fruits and vegetables per day! This is what is highly recommended and heavily advertised nowadays to the general public to stay fit and healthy! Drinking green tea on a regular basis, eating chocolate from time to time, as well as savoring a couple of glasses of red wine per day have been claimed to increase life expectancy even further! Why? The answer is in fact still under scientific scrutiny, but a particular class of compounds naturally occurring in fruits and vegetables is considered to be crucial for the expression of such human health benefits: the polyphenols! What are these plant products really? What are their physicochemical properties? How do they express their biological activity? Are they really valuable for disease prevention? Can they be used to develop new pharmaceutical drugs? What recent progress has been made toward their preparation by organic synthesis? This Review gives answers from a chemical perspective, summarizes the state of the art, and highlights the most significant advances in the field of polyphenol research.
1,902 citations
TL;DR: To confirm the implications of polyphenol consumption for prevention of insulin resistance, metabolic syndrome and eventually type 2 diabetes, human trials with well-defined diets, controlled study designs and clinically relevant end-points together with holistic approaches e.g., systems biology profiling technologies are needed.
Abstract: Polyphenols, including flavonoids, phenolic acids, proanthocyanidins and resveratrol, are a large and heterogeneous group of phytochemicals in plant-based foods, such as tea, coffee, wine, cocoa, cereal grains, soy, fruits and berries. Growing evidence indicates that various dietary polyphenols may influence carbohydrate metabolism at many levels. In animal models and a limited number of human studies carried out so far, polyphenols and foods or beverages rich in polyphenols have attenuated postprandial glycemic responses and fasting hyperglycemia, and improved acute insulin secretion and insulin sensitivity. The possible mechanisms include inhibition of carbohydrate digestion and glucose absorption in the intestine, stimulation of insulin secretion from the pancreatic β–cells, modulation of glucose release from the liver, activation of insulin receptors and glucose uptake in the insulin-sensitive tissues, and modulation of intracellular signalling pathways and gene expression. The positive effects of polyphenols on glucose homeostasis observed in a large number of in vitro and animal models are supported by epidemiological evidence on polyphenol-rich diets. To confirm the implications of polyphenol consumption for prevention of insulin resistance, metabolic syndrome and eventually type 2 diabetes, human trials with well-defined diets, controlled study designs and clinically relevant end-points together with holistic approaches e.g., systems biology profiling technologies are needed.
948 citations
Cites background from "Dietary phenolics: chemistry, bioav..."
...The biochemical properties and resulting health-beneficial bioactivities in different plant groups or even different species are thus discrete, having different impact on different health conditions [3]....
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TL;DR: The significance of phenolic compounds as a source of beneficial compounds for human health and the influence of environmental conditions and processing mechanisms on the phenolic composition of Brassica vegetables are reviewed.
Abstract: Phenolic compounds are a large group of phytochemicals widespread in the plant kingdom. Depending on their structure they can be classified into simple phenols, phenolic acids, hydroxycinnamic acid derivatives and flavonoids. Phenolic compounds have received considerable attention for being potentially protective factors against cancer and heart diseases, in part because of their potent antioxidative properties and their ubiquity in a wide range of commonly consumed foods of plant origin. The Brassicaceae family includes a wide range of horticultural crops, some of them with economic significance and extensively used in the diet throughout the world. The phenolic composition of Brassica vegetables has been recently investigated and, nowadays, the profile of different Brassica species is well established. Here, we review the significance of phenolic compounds as a source of beneficial compounds for human health and the influence of environmental conditions and processing mechanisms on the phenolic composition of Brassica vegetables.
804 citations
Cites background from "Dietary phenolics: chemistry, bioav..."
...Isorhamnetin revealed distinct vasodilator effects in animal models as well, suggesting vascular protective effects in human cardiovascular diseases [17,19,36]....
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...of their potential health-promoting effects [2,17-19]....
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...absorption in the small intestine and colon of humans, as well as the formation and occurrence of metabolites in plasma [17,40]....
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References
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TL;DR: The nature and contents of the various polyphenols present in food sources and the influence of agricultural practices and industrial processes are reviewed, and bioavailability appears to differ greatly between the variousPolyphenols, and the most abundantpolyphenols in the authors' diet are not necessarily those that have the best bioavailability profile.
6,842 citations
TL;DR: Recent studies have begun to shed light on the physiological functions of MAPK cascades in the control of gene expression, cell proliferation and programmed cell death.
Abstract: Mitogen-activated protein kinases (MAPKs) are important signal transducing enzymes, unique to eukaryotes, that are involved in many facets of cellular regulation. Initial research concentrated on defining the components and organization of MAPK signalling cascades, but recent studies have begun to shed light on the physiological functions of these cascades in the control of gene expression, cell proliferation and programmed cell death.
4,973 citations
TL;DR: It is suggested that resveratrol, a common constituent of the human diet, merits investigation as a potential cancer chemopreventive agent in humans.
Abstract: Resveratrol, a phytoalexin found in grapes and other food products, was purified and shown to have cancer chemopreventive activity in assays representing three major stages of carcinogenesis. Resveratrol was found to act as an antioxidant and antimutagen and to induce phase II drug-metabolizing enzymes (anti-initiation activity); it mediated anti-inflammatory effects and inhibited cyclooxygenase and hydroperoxidase functions (antipromotion activity); and it induced human promyelocytic leukemia cell differentiation (antiprogression activity). In addition, it inhibited the development of preneoplastic lesions in carcinogen-treated mouse mammary glands in culture and inhibited tumorigenesis in a mouse skin cancer model. These data suggest that resveratrol, a common constituent of the human diet, merits investigation as a potential cancer chemopreventive agent in humans.
4,786 citations
TL;DR: Flavonoids in regularly consumed foods may reduce the risk of death from coronary heart disease in elderly men and showed an inverse relation with incidence of myocardial infarction.
4,440 citations
TL;DR: It is shown that resveratrol shifts the physiology of middle-aged mice on a high-calorie diet towards that of mice onA standard diet and significantly increases their survival and point to new approaches for treating obesity-related disorders and diseases of ageing.
Abstract: Resveratrol (3,5,49-trihydroxystilbene) extends the lifespan of diverse species including Saccharomyces cerevisiae, Caenorhabditis elegans and Drosophila melanogaster. In these organisms, lifespan extension is dependent on Sir2, a conserved deacetylase proposed to underlie the beneficial effects of caloric restriction. Here we show that resveratrol shifts the physiology of middle-aged mice on a high-calorie diet towards that of mice on a standard diet and significantly increases their survival. Resveratrol produces changes associated with longer lifespan, including increased insulin sensitivity, reduced insulin-like growth factor-1 (IGF-I) levels, increased AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor-c coactivator 1a (PGC-1a) activity, increased mitochondrial number, and improved motor function. Parametric analysis of gene set enrichment revealed that resveratrol opposed the effects of the high-calorie diet in 144 out of 153 significantly altered pathways. These data show that improving general health in mammals using small molecules is an attainable goal, and point to new approaches for treating obesity-related disorders and diseases of ageing.
4,088 citations