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.     

多酚的食物来源及生物有效性

介绍了食品中存在的多种多酚的性质及其含量;分析了农业生产、工业化生产对多酚含量的影响以及综述了目前在多酚的生物有效性方面的研究进展。     

Natural polyphenols: An overview

Plant-derived functional foods are gaining considerable attention due to their safety and therapeutic potentials. Research on plant-based functional foods presents several challenges ranges from hypercholesterolemia to cancer prevention. In last decade, special attention has been paid to edible plants and especially their phytochemicals. Today, there is an increasing interest in their bioactivities provided by these phytochemicals. Polyphenols are the most numerous and widely distributed group of bioactive molecules. Polyphenols have two general classes, one is flavonoids and other is phenolic acids. Among these, flavonoids are further divided into flavones, flavononse, flavonols, flavanols, isoflavones, and phenolic acids are generally classified into hydroxybenzoic and hydroxycinnamic acids. Fruit peel is one of the dense sources for flavonoids and their content may vary from species to species and due to exposure of light. Polyphenols have wide range of molecules and different set of biological activities that are mainly attributed to their structure. Investigations have revealed that polyphenols play a key role to prevent various diseases, like hypercholesterolemia, hyperglycemia, hyperlipidemia, and cancer insurgence. The current review article summarizes the literature pertaining to polyphenols and its allied health benefits.     

Polyphenols: food sources,properties and applications – a review

There is currently much interest in phytochemicals as bioactive compounds of food. The roles of fruit, vegetables and red wine in disease prevention have been attributed, in part, to the antioxidant properties of their constituent polyphenols (vitamins E and C, and the carotenoids). Recent studies have shown that many dietary polyphenolic constituents derived from plants are more effective antioxidants in vitro than vitamins E or C, and thus might contribute significantly to the protective effects in vivo. Polyphenols are abundant micronutrients in our diet, and evidence for their role in the prevention of degenerative diseases is emerging. Dietary polyphenols show a great diversity of structures, ranging from rather simple molecules (monomers and oligomers) to polymers. Higher‐molecular‐weight structures (with molecular weights of ～500) are usually designated as tannins, which refers to their ability to interact with proteins. Among them, condensed tannins (proanthocyanidins) are particularly important because of their wide distribution in plants and their contributions to major food qualities. This paper focuses on polyphenols; we illustrate their sources from food, properties and their beneficial uses.     

松多酚类活性物质抗氧化构效关系与作用机制研究进展

研究表明,心脑血管疾病、癌症、衰老、炎症反应等多种疾病的发生都与活性氧自由基造成的氧化损伤有密切关系。因此,高效、低毒、易得的优良天然抗氧化剂的开发一直是近年研究的热点。松多酚是松科植物树皮及种子壳中富含的多酚类化合物,具有良好的抗氧化活性,是一种高效的自由基清除剂,在现代医药保健行业中日益得到重视。对松多酚的组分及结构分析、抗氧化活性构效关系及其作用机制研究进展作一综述。     

Green Tea Polyphenolic Compounds and Human Health

Polyphenols are a structurally diverse group of compounds that occur widely throughout the plant kingdom. Polyphenolic compounds are ubiquitous in all plant organs and are, therefore, an integral part of the human diet. Recent interest in food phenolics has increased greatly because of the antioxidant and free radical-scavenging abilities associated with some phenolics and their potential effects on human health. Most of the polyphenols in green tea are commonly known as catechins. The regular consumption of green tea is related to benefits in some diseases as atherosclerosis and cancer. Although consumption of dietary polyphenols such as flavonoids has been suggested to have beneficial biological effects, there are considerable evidences to suggest that such compounds are not without risk of adverse effects.     

多酚的功能性质及与蛋白质、多糖相互作用研究进展

多酚是具有多种化学结构的多相分子群,具有很强的抗氧化性、抗菌性以及预防慢性疾病的能力,在食品和医疗领域具有广泛的应用价值。多酚由于含有多个酚羟基基团使其化学稳定性差,生物利用度低,在功能性食品中的应用受到了限制。蛋白质、多酚、多糖相互作用所形成的复合结构能够有效地提高食品的感官品质以及各生物大分子的功能特性。本文对多酚的结构与功能之间的关系,多酚与蛋白质、多糖三者相互作用的机理,多酚对二者功能性质及对改善乳化液性质的影响,进行了综述,以期为多酚在食品工业中的应用提供理论参考。     

Cancer chemoprevention and chemotherapy: dietary polyphenols and signalling pathways

Prevention of cancer through dietary intervention recently has received an increasing interest, and dietary polyphenols have become not only important potential chemopreventive, but also therapeutic, natural agents. Polyphenols have been reported to interfere at the initiation, promotion and progression of cancer. They might lead to the modulation of proteins in diverse pathways and require the integration of different signals for the final chemopreventive or therapeutic effect. Polyphenols have been demonstrated to act on multiple key elements in signal transduction pathways related to cellular proliferation, differentiation, apoptosis, inflammation, angiogenesis and metastasis; however, these molecular mechanisms of action are not completely characterized and many features remain to be elucidated. The aim of this review is to provide insights into the molecular basis of potential chemopreventive and therapeutic activities of dietary polyphenols with emphasis in their ability to control intracellular signalling cascades considered as relevant targets in a cancer preventive approach.     

Green Tea Polyphenolic Compounds and Human Health

Polyphenols are a structurally diverse group of compounds that occur widely throughout the plant kingdom. Polyphenolic compounds are ubiquitous in all plant organs and are, therefore, an integral part of the human diet. Recent interest in food phenolics has increased greatly because of the antioxidant and free radical-scavenging abilities associated with some phenolics and their potential effects on human health. Most of the polyphenols in green tea are commonly known as catechins. The regular consumption of green tea is related to benefits in some diseases as atherosclerosis and cancer. Although consumption of dietary polyphenols such as flavonoids has been suggested to have beneficial biological effects, there are considerable evidences to suggest that such compounds are not without risk of adverse effects. Received: July 23, 2007; accepted August 8, 2007     

植物多酚降血糖机制的研究进展

多酚类化合物是植物的次生代谢产物,广泛存在于自然界中,包括黄酮类化合物、单宁、绿原酸等。研究表明,经常摄入富含多酚类化合物的蔬菜、水果和饮料可以减缓心脑血管疾病、糖尿病、肥胖等慢性代谢疾病甚至癌症的发生和发展。本文从植物多酚可以通过促进胰岛素合成与分泌、抑制葡萄糖转运、调节肠道菌群等方面对血糖起调节作用进行论述,以期为植物多酚降血糖功能提供理论依据。     

Sensorial properties of red wine polyphenols: Astringency and bitterness

Polyphenols have been the subject of numerous research over the past years, being referred as the nutraceuticals of modern life. The healthy properties of these compounds have been associated to a natural chemoprevention of 21st century major diseases such as cancer and neurodegenerative diseases (e.g. Parkinson's and Alzheimer's). This association led to an increased consumption of foodstuffs rich in these compounds such as red wine. Related to the ingestion of polyphenols are the herein revised sensorial properties (astringency and bitterness) which are not still pleasant. This review intends to be an outline both at a sensory as a molecular level of the mechanisms underlying astringency and bitterness of polyphenols. Up-to-date knowledge of this matter is discussed in detail.     

Chemical,biochemical, and biological significance of polyphenols in cereals and legumes

Polyphenols in cereals and legumes have been receiving considerable attention largely because of their adverse influence on color, flavor, and nutritional quality. These compounds belong to the flavonoid and tannin groups and are mostly located in the seed coat or pericarp of the grains. The pearl millet flavonoids have been identified as C‐glycosylflavones by the combined use of paper chromatography and UV spectroscopy. Although nontoxic, physiological and nutritional significance of these compounds occurring in high amounts in the pearl millet grain are still not clearly understood. In view of aesthetic quality, bleaching of the millet grains in acidic solution is recommended. A large proportion of current assays involves spectrophotometry of tannin or its chromogen and tannin‐protein interaction. Sorghum and legume tannins have been characterized as condensed tannins. Several factors such as plant type, age of the plant or plant parts, stage of development, and environmental conditions govern the polyphenol contents in plants. Polyphenols are known to interact with proteins and form tannin‐protein complexes leading to either inactivation of enzymes or making proteins insoluble. These are implicated in decreasing the activities of digestive enzymes, protein and amino acid availabilities, mineral uptake, vitamin metabolism, and depression of growth. Polyphenols are known to cause certain ultrastructural changes in the different parts of experimental animals. A correlation between dietary tannins and occurrence of esophageal cancer has been established. Bird resistance and seed germination in food crops have been correlated to high contents of polyphenols. The antinutritional activity of polyphenols can be reduced by removing polyphenols from the grains by chemical treatments or removing pericarp and testa by pearling. Treatment of alkaline reagents and ammonia can remove 90% of the polyphenols. Supplementation of polyphenols‐rich diet with protein can alleviate the growth‐depressing effect of polyphenols.     

Dietary polyphenols and the prevention of diseases

Polyphenols are the most abundant antioxidants in the diet and are widespread constituents of fruits, vegetables, cereals, dry legumes, chocolate, and beverages, such as tea, coffee, or wine. Experimental studies on animals or cultured human cell lines support a role of polyphenols in the prevention of cardiovascular diseases, cancers, neurodegenerative diseases, diabetes, or osteoporosis. However, it is very difficult to predict from these results the effects of polyphenol intake on disease prevention in humans. One of the reasons is that these studies have often been conducted at doses or concentrations far beyond those documented in humans. The few clinical studies on biomarkers of oxidative stress, cardiovascular disease risk factors, and tumor or bone resorption biomarkers have often led to contradictory results. Epidemiological studies have repeatedly shown an inverse association between the risk of myocardial infarction and the consumption of tea and wine or the intake level of some particular flavonoids, but no clear associations have been found between cancer risk and polyphenol consumption. More human studies are needed to provide clear evidence of their health protective effects and to better evaluate the risks possibly resulting from too high a polyphenol consumption.     

多酚对食源性晚期糖基化终末产物及其诱导的相关疾病的抑制作用研究进展

晚期糖基化终末产物通过引起活性氧产生、激活氧化应激反应从而诱发各种慢性代谢性疾病，如糖尿病性肾病、阿尔茨海默病、动脉粥样硬化和骨关节炎等。因此，晚期糖基化终末产物被认为是一种促进宿主细胞死亡和器官损伤的强毒性分子。多酚是自然界中常见的一种次生代谢产物，其结构多样，具有抗氧化、抗炎、抗菌等多种生物活性。天然产物多酚可通过捕获自由基、阻断炎症信号通路和与微生物相互作用等多种机制减少晚期糖基化终末产物的产生并抑制相关疾病的发生。本文综述了多酚对晚期糖基化产物及相关疾病的抑制作用，以期为多酚抑制晚期糖基化产物的进一步研究提供科学参考。     

多酚类化合物对糖脂代谢影响的研究进展

多酚类化合物是植物的次生代谢产物,广泛存在于食物中,包括黄酮类化合物、咖啡酸、绿原酸等。很多研究报道表明,摄入富含多酚类化合物的饮料、水果和蔬菜可以减缓肥胖、心血管疾病、糖尿病等慢性疾病甚至癌症的发生和发展。很大一部分原因在于其中的多酚类化合物具有抗氧化、抗病菌、增强免疫力、参与营养成分代谢调节的生理活性。本文结合近年来国内外的研究概况,从相关代谢酶活性和基因的表达、胰岛素分泌、营养物质的消化和吸收等方面来论述多酚类化合物对糖、脂代谢的影响。     

An emerging trend in functional foods for the prevention of cardiovascular disease and diabetes: Marine algal polyphenols

Marine macroalgae are gaining recognition among the scientific community as a significant source of functional food ingredients. Due to the harsh environments in which macroalgae survive, they produce unique bioactive compounds that are not found in terrestrial plants. Polyphenols are the predominant bioactive compound in brown algae and are accountable for the majority of its biological activity. Phlorotannins are a type of polyphenol that are unique to marine sources and have exhibited protective effects against hyperglycemia, hyperlipidemia, inflammation and oxidative stress, known risk factors for cardiovascular disease and diabetic complications, in cell culture, animal studies and some human studies. This review updates the information on marine polyphenols, with a particular focus on phlorotannins and their potential health benefits in relation to the prevention and treatment of risk factors for type 2 diabetes and cardiovascular diseases.     

Impact of dietary polyphenols on human platelet function – A critical review of controlled dietary intervention studies

Cardiovascular disease is a chronic disease influenced by many factors, with activated blood platelets being one of them. Platelets play a central role in the formation of plaques within blood vessels, contributing to early inflammatory events. Consumption of diets rich in plant‐based products protects against the development of cardiovascular disease. Polyphenols, which are secondary plant metabolites found in a wide range of foodstuffs and beverages, may be partially responsible for these effects. Their protective properties include inhibitory effects on platelet function in vitro and in vivo. However, the bioavailability of many polyphenols is poor and it is unclear whether sufficient quantities can be obtained by dietary means to exert protective effects. Consequently, this review summarizes 25 well‐controlled human intervention studies examining the effect of polyphenol‐rich diets on platelet function. These studies report a huge variety of research methods, study designs, and study subjects, resulting in controversial assertions. One consistent finding is that cocoa‐related products, however, have platelet‐inhibiting effects when consumed in moderate amounts. To assess whether other classes of dietary polyphenols, or their metabolites, also beneficially affect platelet function requires more well‐controlled intervention studies as well as the adoption of more uniform methods to assess platelet aggregation and activation.