Updated molecular knowledge about histamine biosynthesis by bacteria

Histamine poisoning is caused by the ingestion of food containing high levels of histamine, a biogenic amine. Histamine could be expected in virtually all foods that contain proteins or free histidine and that are subject to conditions enabling microbial activity. In most histamine-containing foods the majority of the histamine is generated by decarboxylation of the histidine through histidine decarboxylase enzymes derived from the bacteria present in food. Bacterial histidine decarboxylases have been extensively studied and characterized in different organisms and two different enzymes groups have been distinguished, pyridoxal phosphate- and the pyruvoyl-dependent. Pyridoxal phosphate-dependent histidine decarboxylases are encountered in gram-negative bacteria belonging to various species. Pyruvoyl-dependent histidine decarboxylases are found in gram-positive bacteria and specially in lactic acid bacteria implicated in food fermentation or spoilage. The molecular organization of the genes involved in histamine production have been elucidated in several histamine-producer bacteria. This molecular knowledge has led to the development of molecular methods for the rapid detection of bacteria possessing the ability to produce histamine. The detection of histamine-producer bacteria is of great importance for its potential health hazard as well as from an economic point of view since products exceeding recommended limits can be refused in commercial transactions.     

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.     

Updated knowledge about the presence of phenolic compounds in wine

Phenolic compounds are partly responsible for the color, astringency, and bitterness of wine, as well as for numerous physiological properties associated with wine consumption. Mass spectrometry has allowed for great progress in the identification and characterization of wine polyphenols. The aim of the present article is to summarize the numerous advances recently achieved in this field. The main type of phenolic compounds found in wine, including hydroxybenzoic and hydroxycinnamic acids, stilbenes, flavones, flavonols, flavanonols, flavanols, and anthocyanins, are firstly described. Chemical reactions and mechanisms involving phenolic compounds during winemaking are also extensively discussed, including enzymatic and chemical oxidation reactions, direct and acetaldehyde-mediated anthocyanin-tannin condensation reactions, acetaldehydemediated and glyoxylic acid-mediated tannin-tannin condensation reactions and, C-4/C-5 anthocyanin cycloaddition reactions with 4-vinylphenols, vinylflavanols and pyruvic acid, among others, leading to the formation of pyranoanthocyanins. Useful mass spectral data of well-known and novel phenolic compounds recently identified in wine, and details related to their fragmentation pathway according to different ionization techniques, are given.     

食品多酚与蛋白相互作用及其对多酚生物可利用性影响的研究进展

多酚和蛋白质的相互作用是近几十年来多酚类化合物与生物大分子作用研究的重点。食品多酚具有多种功能活性,但是由于受其他食品组分、加工条件和消化环境等各种因素的影响,其生物可利用率较低,对人体的健康功效受到严重影响。因此,该文综述了近些年来国内外关于食品多酚与蛋白的相互作用类型及其对多酚生物可利用性影响的研究进展,以期为提高多酚类食品的健康功能品质提供一定的指导依据。     

Specialty seeds: Nutrients,bioactives, bioavailability,and health benefits: A comprehensive review

Seeds play important roles in human nutrition and health since ancient time. The term “specialty” has recently been applied to seeds to describe high-value and/or uncommon food products. Since then, numerous studies have been conducted to identify various classes of bioactive compounds, including polyphenols in specialty seeds. This review discusses nutrients, fat-soluble bioactives, polyphenols/bioactives, antioxidant activity, bioavailability, health benefits, and safety/toxicology of commonly consumed eight specialty seeds, namely, black cumin, chia, hemp, flax, perilla, pumpkin, quinoa, and sesame. Scientific results from the existing literature published over the last decade have been compiled and discussed. These specialty seeds, having numerous fat-soluble bioactives and polyphenols, together with their corresponding antioxidant activities, have increasingly been consumed. Hence, these specialty seeds can be considered as a valuable source of dietary supplements and functional foods due to their health-promoting bioactive components, polyphenols, and corresponding antioxidant activities. The phytochemicals from these specialty seeds demonstrate bioavailability in humans with promising health benefits. Additional long-term and well-design human intervention trials are required to ascertain the health-promoting properties of these specialty seeds.     

姜黄素生理活性、代谢以及生物利用度的研究进展

姜黄素是一种多酚类化合物,着色能力强,是世界上销量最大的七大天然食用色素之一,是被WHO和FDA公认的天然食品添加剂。除此之外,姜黄素因其具有分子中含有多个双键,同时还有酚羟基和羰基等活性基团,在抗肿瘤、抗炎、抗氧化、清除自由基、抗微生物以及对心血管系统、消化系统等多方面均有疗效,但其生物利用度低限制了在医药方面的应用,因此如何提高姜黄素的生物利用度成为国内外研究者共同关注的课题。该文从国内外研究现状出发,对姜黄素的生理活性及应用进行概括,并对姜黄素体内代谢途径进行综述,分析指出姜黄素生物利用度低的原因,并介绍研究姜黄素生物利用度的模型和提高其生物利用度的方法,为全面系统研究姜黄素生物利用度打下基础。     

姜黄素生理活性、代谢以及生物利用度的研究进展

为提升姜黄素微胶囊的作用效果,本文采用单因素及正交方法优化姜黄素微胶囊制备工艺,并通过番泻叶诱导的小鼠腹泻模型考察微胶囊作用效果。结果表明,经优化后确定包埋工艺为海藻酸钠、海绵胶煤炱菌多糖、姜黄素、吐温80、CaCl₂浓度分别为2.5%、0.15%、0.4%、0.3%、2.0%,包埋时间1.5 h,姜黄素微胶囊包埋率达到92.26%。采用该微胶囊灌胃腹泻小鼠,发现微胶囊能通过小鼠TRL4/NF-κB通路提升机体氧化应激能力,降低促炎因子IL-1β、TNF-α、IL-6并促进抗炎因子IL-10释放,通过Nrf2信号通路提升小鼠肠道抗氧化性,促进超氧化物歧化酶SOD生成,抑制丙二醛MDA生成,最终,在抗氧化和抗炎的共同作用下维持小鼠肠道屏障,达到有效干预小鼠腹泻的目的,为姜黄素微胶囊干预腹泻制剂的推广应用奠定了理论基础。     

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.     

An updated review of dietary isoflavones: Nutrition,processing, bioavailability and impacts on human health

Isoflavones (genistein, daidzein, and glycitein) are bioactive compounds with mildly estrogenic properties and often referred to as phytoestrogen. These are present in significant quantities (up to 4–5 mg·g^?1 on dry basis) in legumes mainly soybeans, green beans, mung beans. In grains (raw materials) they are present mostly as glycosides, which are poorly absorbed on consumption. Thus, soybeans are processed into various food products for digestibility, taste and bioavailability of nutrients and bioactives. Main processing steps include steaming, cooking, roasting, microbial fermentation that destroy protease inhibitors and also cleaves the glycoside bond to yield absorbable aglycone in the processed soy products, such as miso, natto, soy milk, tofu; and increase shelf lives. Processed soy food products have been an integral part of regular diets in many Asia–Pacific countries for centuries, e.g. China, Japan and Korea. However, in the last two decades, there have been concerted efforts to introduce soy products in western diets for their health benefits with some success. Isoflavones were hailed as magical natural component that attribute to prevent some major prevailing health concerns. Consumption of soy products have been linked to reduction in incidence or severity of chronic diseases such as cardiovascular, breast and prostate cancers, menopausal symptoms, bone loss, etc. Overall, consuming moderate amounts of traditionally prepared and minimally processed soy foods may offer modest health benefits while minimizing potential for any adverse health effects.     

多酚-膳食纤维相互作用及其影响多酚生物利用率研究进展

多酚广泛存在于植物源食品中,具有潜在的促进人体健康作用。天然多酚绝大多数以结合态存在,并且多酚与膳食纤维结合的比例要显著高于其他基质。多酚和膳食纤维的相互作用在食品加工和机体消化等环节会受到不同因素的影响,从而发生复杂的变化。近年来,多酚-膳食纤维相互作用对多酚生物利用率的影响已经受到了越来越多的关注。本文首先分析了多酚与膳食纤维的不同结合方式,随后总结了影响多酚与膳食纤维相互作用的主要因素,最后探讨了两者相互作用对于多酚生物利用率的影响,可为改善多酚食品的营养健康品质以及提高多酚的生物利用率提供一定的理论参考。     

魔芋葡甘聚糖的特性、保健功能及作用

魔芋葡甘聚糖(KGM)是一种高分子量的水溶性膳食纤维，具有多种良好的食品学特性，其保健功能也越来越受到医学界和食品界的重视。综述了魔芋葡甘聚糖的特性、保健功能以及国内外在食品、农业、工业等方面利用魔芋葡甘聚糖的现状。     

Effect of grape polyphenols on lactic acid bacteria and bifidobacteria growth: resistance and metabolism

Food polyphenols are able to selectively modify the growth of susceptible micro-organisms. This study describes the effect of a flavan-3-ol enriched grape seed extract (GSE) on the growth of several lactic acid bacteria (LAB) and bifidobacteria and the ability of the resistant strains to metabolize these compounds. Streptococcus thermophilus, Lactobacillus fermentum, Lactobacillus acidophilus and Lactobacillus vaginalis strains showed a remarkable sensitivity to the phenolic extracts assayed, including a GSE fraction consisting mainly in (+)-catechin and (−)-epicatechin (GSE-M). On the other hand, Lactobacillus plantarum, Lactobacillus casei, and Lactobacillus bulgaricus strains reached maximal growth with the GSE fractions, including a rich-oligomeric (GSE-O) fraction. Within bifidobacteria, Bifidobacterium lactis BB12 showed the highest sensitivity to the phenolic extracts assayed, whereas Bifidobacterium breve 26M2 and Bifidobacterium bifidum HDD541 reached maximum growth in presence of GSE-O and GSE-M fractions. Metabolism of flavan-3-ols by LAB and bifidobacteria resistant strains was investigated in vitro. The results revealed that only L. plantarum IFPL935 was able to metabolize the polyphenols studied by means of galloyl-esterase, decarboxylase and benzyl alcohol dehydrogenase activities that led to the formation of gallic acid, pyrogallol and catechol, respectively. An unknown metabolite that does not exhibit a phenolic-acid-type structure was also detected, which suggests a new enzyme activity in L. plantarum IFPL935 able to degrade flavan-3-ol monomers.     

Mind the gap—deficits in our knowledge of aspects impacting the bioavailability of phytochemicals and their metabolites—a position paper focusing on carotenoids and polyphenols

Various secondary plant metabolites or phytochemicals, including polyphenols and carotenoids, have been associated with a variety of health benefits, such as reduced incidence of type 2 diabetes, cardiovascular diseases, and several types of cancer, most likely due to their involvement in ameliorating inflammation and oxidative stress. However, discrepancies exist between their putative effects when comparing observational and intervention studies, especially when using pure compounds. These discrepancies may in part be explained by differences in intake levels and their bioavailability. Prior to exerting their bioactivity, these compounds must be made bioavailable, and considerable differences may arise due to their matrix release, changes during digestion, uptake, metabolism, and biodistribution, even before considering dose‐ and host‐related factors. Though many insights have been gained on factors affecting secondary plant metabolite bioavailability, many gaps still exist in our knowledge. In this position paper, we highlight several major gaps in our understanding of phytochemical bioavailability, including effects of food processing, changes during digestion, involvement of cellular transporters in influx/efflux through the gastrointestinal epithelium, changes during colonic fermentation, and their phase I and phase II metabolism following absorption.