Walnuts (Juglans regia) Chemical Composition and Research in Human Health

Walnuts are among the most widely consumed commercially grown tree nuts in the world. Many health benefits have been claimed for the consumption of these, including reduced risk of cardiovascular disease, coronary heart disease, type II diabetes treatment, and prevention and treatment of certain cancers, and the lessening of symptoms attributed to age-related and other neurological disorders. The health-promoting benefits of walnut consumption are ascribed to its fatty acid profile, which is rich in polyunsaturated fatty acids with a particularly high ω3:ω6 ratio—the highest among all the tree nuts. The content of polyphenols and other phytochemicals in walnuts, with their claimed cytotoxic properties, also make them an attractive candidate for research for the prevention of free radical-induced nucleic acid damage. Research of walnut consumption in humans and animals employing a range of data sets and statistical methods suggest that walnuts may be considered a safe potential nutraceutical or possibly pharmaceutical substance. Nevertheless, few reviews of scientific research on the proposed benefits of these nuts exist, in spite of the numerous claims attributed to them in the lay media. This brief review article attempts to disseminate much of the information surrounding walnut consumption, and human health benefits, to other scientists and the interested general reader.     

Impact of ethanol content on the scavenging activities of oak wood C‐glycosidic ellagitannins. Application to the evaluation of the nutritional status of spirits

As a consequence of their structure, ellagitannins have a high level of activity in terms of their oxidative properties. In particular, their scavenging activity is often presented as a noteworthy parameter, since polyphenols have a beneficial impact on human health. A large variety of spirits, brandies and whiskeys are aged in barrels or receive a wood extract rich in polyphenols. Although spirits (alcoholic beverages) represent a very dynamic market with significant growth, very few scientific papers have been published on this topic, or have justified specific research in this field. Firstly, the scavenging properties of ellagitannins when measured in a solution are presented. An oak wood extract was fractionated by gel chromatography to obtain different fractions with different polymeric levels. It is particularly clear that the oligomer forms are the most efficient by comparison with low‐weight and high‐weight fractions. A mixture of ellagitannins has a higher scavenging intensity than the pure molecule; this illustrates the synergic effect of polyphenols. The scavenging activity of different commercial spirits depends on the presence and quantities of ellagitannins. As an example, the percentage of scavenged superoxide anion radicals represents 70 and 18%, respectively, for spirits aged in a barrel (12 years) and white spirits. In a second step, details of the influence of ethanol on the antioxidant properties of ellagitannins are provided. In particular, alcohol increases the scavenging activity of ellagitannins from 0 to 25% vol., and higher concentrations present a certain degree of pro‐oxidant activity. The chemical study of ellagitannin scavenging properties in solution is confirmed by means of a specific in vitro investigation on the DNA extracted from cells, and directly on the cells. Copyright © 2013 The Institute of Brewing & Distilling     

Amalgamation of polyphenols and probiotics induce health promotion

ABSTRACT

The residing microbiome with its vast repertoire of genes provide distinctive properties to the host by which they can degrade and utilise nutrients that otherwise pass the gastro-intestinal tract unchanged. The polyphenols in our diet have selective growth promoting effects which is of utmost importance as the state of good health has been linked to dominance of particular microbial genera. The polyphenols in native form might more skilfully exert anti-oxidative and anti-inflammatory properties but in a living system it is the microbial derivatives of polyphenol that play a key role in determining health outcome. This two way interaction has invoked great interest among researchers who have commenced several clinical surveys and numerous studies in in-vitro, simulated environment and living systems to find out in detail about the biomolecules involved in such interaction along with their subsequent physiological benefits. In this review, we have thoroughly discussed these studies to develop a fair idea on how the amalgamation of probiotics and polyphenol has an immense potential as an adjuvant therapeutic for disease prevention as well as treatment.     

Updated knowledge about polyphenols: functions, bioavailability, metabolism, and health

Polyphenols are important constituents of food products of plant origin. Fruits, vegetables, and beverages are the main sources of phenolic compounds in the human diet. These compounds are directly related to sensory characteristics of foods such as flavor, astringency and color. Polyphenols are extensively metabolized both in tissues and by the colonic microbiota. Normally, the circulating polyphenols are glucuronidated and/or sulphated and no free aglycones are found in plasma. The presence of phenolic compounds in the diet is beneficial to health due to their antioxidant, anti-inflammatory, and vasodilating properties. The health effects of polyphenols depend on the amount consumed and their bioavailability. Moreover, polyphenols are able to kill or inhibit the growth of microorganisms such as bacteria, fungi, or protozoans. Some dietary polyphenols may have significant effects on the colonic flora providing a type of prebiotic effect. The anti-nutrient properties of polyphenols are also discussed in this paper. The antioxidant, anti-inflammatory, vasodilating, and prebiotic properties of polyphenols make them potential functional foods.     

Ellagitannins, ellagic acid and their derived metabolites: A review about source, metabolism, functions and health

Ellagitannins (ETs) and ellagic acid (EA) are polyphenols present in some fruits, nuts and seeds, such as pomegranates, black raspberries, raspberries, strawberries, walnuts and almonds. ETs are hydrolyzed to EA under physiological conditions in vivo and EA is then gradually metabolized by the intestinal microbiota to produce different types of urolithins. Epidemiological evidence indicates that intake of ET and EA-rich foods may be protective against certain chronic diseases, although in vitro results often do not coincide with the findings of in vivo studies. This could be explained by the low bioavailability of ETs and EA antioxidant and the fact that urolithins are not as potent antioxidants as ellagitannins. On the other hand, urolithins could display estrogenic and/or anti-estrogenic activity and tissue disposition studies reveal that urolithins are enriched in prostate, intestinal, and colon tissues in mouse, which could explain why urolithins inhibit prostate and colon cancer cell growth. Moreover, antiproliferative and apoptosis-inducing activities of EA and urolithins have been demonstrated by the inhibition of cancer cell growth. The present work reviews the source, dietary intake, metabolism, functions and effects of ETs, EA and their derivate metabolites. Moreover, prebiotic, antioxidant and anti-inflammatory effects are also discussed.     

糙米酚类物质对淀粉消化特性的影响研究进展

糖尿病等慢性病是全球范围内重要的公共卫生问题。淀粉摄入是导致餐后血糖升高的主要原因之一。近年来研究表明，多酚类物质能够延缓淀粉的消化速率。糙米富含丰富的酚类物质，作为重要的全谷物来源，其营养健康功效在全世界得到广泛共识。糙米酚类物质特有基团如酚羟基对消化酶类产生一定的抑制作用，在加工过程中淀粉自身结构的改变也使消化酶类对其的作用减小，不仅能有效控制淀粉的消化速率及消化率，还能改善食品品质。本文从糙米中酚类物质及其抗氧化活性、淀粉消化过程、糙米多酚对淀粉消化特性的影响及其作用机制等几个方面进行综述，旨在阐明全谷物糙米酚类物质延缓淀粉消化的科学依据，为开发适用于慢性病人群、肥胖人群、超重人群、老年人群等的全谷物糙米基和淀粉基食品提供参考。     

植物多酚与淀粉的分子相互作用研究进展

淀粉是食品工业的重要原料之一,同时也是人体主要的供能物质。植物多酚是一类广泛存在于植物中且对人体健康有益的活性物质。植物多酚与淀粉的分子相互作用会影响淀粉基食品在加工和贮藏过程中的品质（如质构、风味及色泽等）及营养特性。本文在查阅和整理国内外有关文献和研究的基础上,对植物多酚与淀粉的分子相互作用及其对淀粉和植物多酚相关性质的影响进行综述,包括植物多酚与淀粉的复合物形成方式（以疏水作用力为主的V型复合物和以氢键为主的非V型复合物）,其相互作用对淀粉理化性质（糊化性质、回生性质和流变性质等）、微观结构和消化特性的改变及其对植物多酚的保护及缓释作用,以期为植物多酚在淀粉的加工、贮藏及其他相关领域的资源化利用提供有益的帮助与参考。     

Biologically Active Compounds from Hops and Prospects for Their Use

Although female cones of the hop plant (Humulus lupulus) are known primarily as raw material supplying characteristic bitterness and aroma to beer, their equally significant health‐promoting effects have been known to mankind for several thousand years and hop is a plant traditionally utilized in folk medicine. This paper summarizes the scientific knowledge on the effects of all 3 major groups of secondary metabolites of hops; polyphenols, essential oils, and resins. Because of their chemical diversity, it is no coincidence that these compounds exhibit a wide range of pharmacologically important properties. In addition to antioxidant, anti‐inflammatory, and anticancer‐related properties, particular attention is being paid to prenylflavonoids that occur almost exclusively in hops and are considered to be some of the most active phytoestrogens known. Hop oils and resins are well known for their sedative and other neuropharmacological properties, but in addition, these compounds exhibit antibacterial and antifungal effects. Recently, alpha bitter acids have been shown to block the development of a number of complex lifestyle diseases that are referred to by the collective name “metabolic syndrome.” Information presented in this review confirms the significant potential for the use of hops in the pharmaceutical industry and provides an understanding of beer as a natural drink that, although moderately consumed, may become a source of many health‐promoting compounds.     

Fruit Polyphenols: A Review of Anti-inflammatory Effects in Humans

Underlying etiological factors in the development of obesity-related chronic diseases are long-term imbalances of oxidative and inflammatory stress leading to tissue dysfunction, damage, and ultimately failure. Poor dietary quality contributes significantly to the oxidative and inflammatory status of an individual. Conversely, various dietary approaches, including specific dietary factors can mitigate or prevent the occurrence of these risk-conferring imbalances brought about by modern lifestyle. Plant-derived polyphenolic compounds are well known for their antioxidant properties. Recent evidence indicates these compounds may confer anti-inflammatory and/or inflammatory response stabilizing activities, which would have important implications in health maintenance and disease risk reduction. Commonly consumed fruits, such as grapes, berries, and oranges/orange juice, contain polyphenolic compounds that have been studied for their effects on inflammation, but the nature and extent of their effects in humans remain unclear. Therefore, this article aims to provide a comprehensive overview of human clinical trials investigating the acute and chronic (feeding) effect of polyphenols from commonly consumed fruits or their derived products on inflammation.     

Cocoa polyphenols and their influence on parameters involved in ex vivo skin restructuring

Polyphenols in general are compounds that are known to promote health and have a preventive effect against various chronic diseases. The influence of cocoa polyphenols on skin, however, has scarcely been studied from a histological point of view. The aim of this study is to assess the influence of cocoa polyphenols on several indicators of skin elasticity and skin tonus, namely, glycosaminoglycans and collagen I, III and IV. This was carried out by using a model of ex vivo human skin explants maintained in survival, on which a cocoa polyphenol extract was applied. After processing by standard histological techniques (fixation, paraffin embedding, sectioning, staining, immunostaining and microscopical observation), the influence of cocoa polyphenols on the evaluated parameters was quantified by image analysis. The results obtained show that cocoa polyphenols exhibit a positive action on the parameters assessed, and the dose at which they improve the most parameters associated with skin tonus and elasticity was determined. Their activity was compared with a commercially available product, and the results obtained show that their efficacy is equivalent. Moreover, an enhancing effect of cocoa butter on activity of cocoa polyphenol was highlighted. Now that the properties of cocoa polyphenols on ex vivo skin restructuring parameters have been assessed, the next step could include their evaluation in vivo.     

Polyphenols in chocolate: is there a contribution to human health?

Recently, polyphenols have gained much more attention, owing to their antioxidant capacity (free radical scavenging and metal chelating) and their possible beneficial implications in human health, such as in the treatment and prevention of cancer, cardiovascular disease, and other pathologies. Cocoa is rich in polyphenols particularly in catechins (flavan-3-ols) and procyanidins. Polyphenol contents of cocoa products such as dark chocolate, milk chocolate and cocoa powder have been published only recently. However, the data vary remarkably due to the quantity of cocoa liquor used in the recipe of the cocoa products but also due to the analytical procedure employed. For example, results obtained by a colourimetric method were 5–7 times higher for the same type of product than results obtained by high performance liquid chromatography (HPLC). In 1994, the per head consumption of chocolate and chocolate confectionery in the European Union ranged from 1.3 kg/year in Portugal to 8.8 kg/year in Germany. In general, consumers in the Northern countries consume on average more than people in the South. Thus, chocolate can be seen as a relevant source for phenolic antioxidants for some European population. However, this alone does not imply, that chocolate could be beneficial to human health. Some epidemiological evidence suggests a beneficial effect to human health by following a polyphenol-rich diet, namely rich in fruits and vegetables and to a less obvious extent an intake of tea and wine having a similar polyphenol composition as cocoa. In many experiments cellular targets have been identified and molecular mechanisms of disease prevention proposed, in particular for the prevention of cancer and cardiovascular diseases as well as for alleviating the response to inflammation reactions. However, it has to be demonstrated, whether polyphenols exert these effects in vivo. One pre-requisite is that the polyphenols are absorbed from the diet. For monomeric flavonoids such as the catechins, there is increasing evidence for their absorption. For complex phenols and tannins (procyanidins) these questions have to be addressed for the future. Some indication for the absorption of procyanidins derive from studies with the human colon cancer cell line Caco-2, believed to be a valuable model for passive intestinal absorption as proposed for polyphenols. However, it has to be clarified which concentration is effective and what concentrations can be expected from food intake. Another open question is related to polyphenol metabolism. For example, much effort has been invested to show antioxidative effects of free unbound polyphenols, especially of catechins and the flavonol quercetin. However, only a very small part can be found in plasma in the free form but conjugated or even metabolised to several phenolic acids and other ring scission products. From the papers reviewed, it is as yet to early to give an answer to the question, whether chocolate and/or other sources rich in catechins and procyanidins are beneficial to human health. Even though some data are promising and justify further research in the field, it has to be shown in future, whether the intake of these functional compounds and/or their sources is related to measurable effects on human health and/or the development of diseases.     

鞣花酸代谢产物——尿石素的研究进展

鞣花单宁和鞣花酸是广泛分布于多种蔬菜、水果和坚果中的多酚类抗氧化剂,其在胃肠道的吸收较差,生物利用率较低,但部分会被哺乳动物肠道微生物转化为更易吸收的尿石素类代谢产物。因此,人们推测这些代谢产物可能为鞣花单宁及鞣花酸发挥生物学活性的最终物质基础。本文对近年来国内外有关尿石素化学性质和抗氧化、抗炎、抗癌以及调节肠道菌群等生物活性的研究进行综述,以期为富含鞣花单宁及鞣花酸类食品的科学利用提供借鉴。     

The importance of almond (Prunus amygdalus L.) and its by-products

Almond fruit consists of three or correctly four portions: kernel or meat, middle shell, outer green shell cover or almond hull and a thin leathery layer known as brown skin of meat or seedcoat. The nutritional importance of almond fruit is related to its kernel. Other parts of fruit such as shells and hulls were used as livestock feed and burned as fuel. In the past decades, different phenolic compounds were characterised and identified in almond seed extract and its skin, shell and hull as almond by-products. In addition, polyphenols are abundant micronutrients in the human diet, and evidence for their role in the prevention of degenerative diseases such as cancer and cardiovascular diseases is emerging. The health effects of polyphenols depend on the amount consumed and on their bioavailability. In this contribution, various phenolic compounds present in almond and its by-products, their antioxidant properties and potential use as natural dietary antioxidant, as well as their other beneficial compounds and applications are reviewed.     

葡萄渣多酚的分布、生物活性及其在食品中的 应用研究进展

许多水果在加工过程中会产生大量的副产物,如葡萄酒酿造过程中产生的葡萄果渣(grape pomace,GP),由于其中含有丰富的生物活性物质,如多酚、膳食纤维、有机酸和不饱和脂肪酸等,已成为医药、化妆品和食品工业提取植物活性物质的廉价来源。尤其是酚类化合物受到越来越多的关注,葡萄渣中的酚类化合物是一类次生代谢产物,主要包括类黄酮、花青素和白藜芦醇等,很多研究已经证实这些酚类化合物具有抗氧化、抗菌、抗病毒、抗炎和抗癌等生物活性,因此,如何从葡萄渣中提取多酚化合物并将其开发成功能性食品配料,成为越来越多的企业和学者的关注。在此本文对GP多酚的组成分布、生物活性、在食品中的稳定性及其应用等进行了较全面的总结,旨在为葡萄渣多酚功能性食品的开发提供参考。     

Carob Kibble: A Bioactive‐Rich Food Ingredient

Carob (Ceratonia siliqua L.) is well known for its valuable locust bean gum obtained from the carob seeds. Separation of seeds from the pod leaves behind the carob kibble which is a good source of dietary fiber, sugars, and a range of bioactive compounds such as polyphenols and pinitol. Bioactive compounds present in carob kibble have been found to be beneficial in the control of many health problems such as diabetes, heart diseases, and colon cancer due to their antidiabetic, antioxidant, and anti‐inflammatory activities. Carob kibble has substantial potential to be used as a food ingredient. This article focuses on the composition, health benefits, and food applications of carob kibble.     

Bioactivation of Phytoestrogens: Intestinal Bacteria and Health

Phytoestrogens are polyphenols similar to human estrogens found in plants or derived from plant precursors. Phytoestrogens are found in high concentration in soya, flaxseed and other seeds, fruits, vegetables, cereals, tea, chocolate, etc. They comprise several classes of chemical compounds (stilbenes, coumestans, isoflavones, ellagitannins, and lignans) which are structurally similar to endogenous estrogens but which can have both estrogenic and antiestrogenic effects. Although epidemiological and experimental evidence indicates that intake of phytoestrogens in foods may be protective against certain chronic diseases, discrepancies have been observed between in vivo and in vitro experiments. The microbial transformations have not been reported so far in stilbenes and coumestans. However, isoflavones, ellagitanins, and lignans are metabolized by intestinal bacteria to produce equol, urolithins, and enterolignans, respectively. Equol, urolithin, and enterolignans are more bioavailable, and have more estrogenic/antiestrogenic and antioxidant activity than their precursors. Moreover, equol, urolithins and enterolignans have anti-inflammatory effects and induce antiproliferative and apoptosis-inducing activities. The transformation of isoflavones, ellagitanins, and lignans by intestinal microbiota is essential to be protective against certain chronic diseases, as cancer, cardiovascular disease, osteoporosis, and menopausal symptoms. Bioavailability, bioactivity, and health effects of dietary phytoestrogens are strongly determined by the intestinal bacteria of each individual.     

Unlocking the potential of olive residues for functional purposes: update on human intervention trials with health and cosmetic products

Olive mill waste (OMW) is a promising source of valuable compounds such as polyphenols, terpenes, sterols, and other bioactive compounds, which are of interest to the pharmaceuticals and cosmeceutical industries. This review examines the potential of OMW extracts for health and beauty applications based on evidence reports from human clinical trials. The results achieved to date indicate health-enhancing properties, but little is known about the underlying mechanisms of action, dose–response relationships, and long-term impacts. Therefore, while olive by-products, extracted using eco-friendly methods, present opportunities for the development of high-value health and cosmetic products, further studies are necessary to determine the full range of their effects and establish specific therapeutic strategies. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

A Review on the Potential Human Health Benefits of the Black Walnut: A Comparison with the English Walnuts and Other Tree Nuts

The aim of this review was to evaluate the potential human health benefits of the Black walnut by comparing its compositional similarities and differences with other nuts, particularly the English walnut. The Black walnut contains higher levels of monounsaturated fatty acids and antioxidants, such as the polyphenols and γ-tocopherol, compared to English walnut. These components have been correlated with the prevention and/or attenuation of several types of diseases, including cancer, diabetes, and neurodegenerative conditions. Other nutrients that are also present in the Black walnut include dietary fiber, folate, phytosterols, protein, melatonin, etc., which have been linked with multiple human health promoting properties. Based primarily on its phytochemical composition, the Black walnut is a potentially potent, yet critically understudied, dietary system for promoting human health.     

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.