原花青素的研究进展

原花青素是一类广泛存在于自然界中的黄烷-3-醇类化合物。本文详细整理国内外有关原花青素的报道,就其化学结构、生物活性、吸收代谢和毒理学特性做详细综述。其中,原花青素的化学结构根据其聚合度分类,结合结构单元、连接方式、空间构型和取代基的不同,并配结构图列举说明每种类型;原花青素有很强的生物活性,如抗氧化活性、防治心血管疾病、抗癌、抗高血压、降血脂、降血糖等;原花青素的吸收代谢包括体外Caco-2细胞模型和体内代谢的研究;毒理学研究表明原花青素的安全性很高。本文结合国内外的最新文献,较为全面地介绍生物活性强、食源性和低毒性的原花青素类成分,为该类成分的进一步研究提供参考。     

荔枝核中黄烷-3-醇的鉴定及原花青素的提取

采用95%（V/V）、50%（V/V）醇提荔枝核,经石油醚、乙酸乙酯、正丁醇依次萃取后,再利用硅胶柱层析等方法分离纯化,得到化合物Ⅰ,通过理化性质和波谱技术,鉴定为黄烷-3-醇类化合物表儿茶素.原花青素是由多羟基黄烷-3-醇单元构成的低聚体和多聚体,由不同数量的儿茶素或表儿茶素结合而成,通过单因素实验和L16（45）正交实验,确定原花青素的最佳提取工艺.最佳提取条件为：乙醇浓度50%,浸提温度60℃,料液比1：20（W/V）、浸提时间3h.最佳条件下收率为5.05%.     

黄烷醇类化合物的药理活性研究进展

黄烷醇类化合物是一类常见的天然植物多酚类化合物包括儿茶素类、花色素类及黄酮类等化合物,大部分存在于多种木本植物组织中,如山楂、葡萄、可可粉、苹果及草莓等,与日常的饮食有着非常密切的联系。近年以来,国内外许多学者对黄烷醇类化合物进行了研究,多项研究结果表明黄烷醇类化合物具有多种保健功能及生物活性作用,如清除自由基、抗氧化、抗肿瘤、抗炎、抗真菌、降血脂、保护肝脏、保护心血管等,也已被很多的药物科学研究所证实,并成为当今开发研究的热点。本文主要对天然黄烷醇类化合物的来源及多种药理活性等作用进行了综述,并对我国黄烷醇类化合物开发的应用前景提出了一些建议,对黄烷醇类化合物取代合成药物应用于保健食品等行业提供了较好的参考。     

苹果酒中酚酸、黄烷-3-醇的检测

以小国光(Ralls)和富士(Fuji)及其所酿制的新鲜苹果酒为试验材料,采用反相高效液相色谱法测定分析苹果原汁、发酵中酒样和苹果成品酒中11种酚酸、5种黄烷-3-醇的含量。结果表明:苹果和苹果酒中存在4种酚酸(原儿茶酸、绿原酸、咖啡酸、对-香豆酸)、2种黄烷-3-醇(儿茶素和表儿茶素);不同品种的苹果原汁和苹果成品酒中酚类物质的含量都存在显著差异。其中,小国光苹果和小国光苹果酒中的酚类物质总含量较高;对于每个品种,绿原酸都是最主要的酚酸类物质,含量最高的黄烷-3-醇类物质都是表儿茶素。随着发酵过程的进行,苹果酒中酚类物质的含量有不同程度的增加。其增加趋势为S型曲线,即先平缓再较快再平缓。     

玉米黄烷酮-3-羟化酶原核表达条件对香橙素生成量的影响

香橙素是类黄酮代谢途径中重要的中间化合物,黄烷酮-3-羟化酶(flavanone-3-hydroxylase,F3H)能以柚皮素为底物催化C3位接羟基从而生成香橙素.为实现香橙素绿色发展,该研究利用微生物法,对来自玉米的Zmf3h构建大肠杆菌原核表达系统后诱导ZmF3H蛋白表达.通过发酵实验验证ZmF3H在胞内可溶性表...     

黄烷醇类化合物抗氧化性的构效关系研究

本文采用分子力学和量子化学从头计算方法，系统地计算了阿福豆素、儿茶素和培儿茶素等三种黄烷醇类化合物的能量与电子结构，讨论了黄烷醇类化合物各种立体异构体的结构稳定性和酚羟基反应活性问题。另外计算了黄烷醇类化合物在脱氢氧化反应过程中生成自由基和类醌化合物的能量变化和电子结构的变化，根据计算结果阐明了黄烷醇类化合物抗氧化性顺序，并从能量和电子结构的角度给予了理论解释。     

食品污染物3-氯-1,2-丙二醇毒理作用的研究进展

氯丙醇类化合物3-氯-1,2-丙二醇(3-MCPD)是目前国际上广为关注的食品污染物,最初发现在酸水解植物蛋白加工而成的食品中.近年来,许多食品特别是精制油中发现大量3-MCPD脂类,其能够在体内通过代谢途径产生3-MCPD.研究发现3-MCPD在啮齿类动物中存在明显的毒性作用,且具有种属和位点特异性.结合国内外毒理学研究成果,概述3-MCPD体内代谢途径,详细综述其急性毒理、致癌性以及遗传、生殖、免疫、神经毒性机制的研究进展,并展望了3-MCPD毒理学评价进一步研究的方向.     

荔枝皮中原花青素提取工艺优化及其黄烷-3-醇HPLC分析

优化荔枝皮中原花青素超声波辅助提取工艺,并对其黄烷-3-醇类成份进行分析定量。用Box-Behnken Design设计考察荔枝皮粉碎度、料液比、超声时间和超声波功率4个因素对荔枝皮中原花青素提取的影响程度。在最佳工艺参数条件下,超声破碎荔枝皮1次,采用铁盐催化比色法和HPLC法分析得出荔枝皮黄烷-3-醇类成份及含量。荔枝皮中原花青素超声波辅助提取最佳工艺参数为荔枝皮粉碎度71.91目、料液比1:29.97(m:V)、超声时间21.75min和超声波功率390.48W。在最佳提取工艺参数下超声提取荔枝皮中原花青素1次,其吸光度值为2.157Abs,与原花青素吸光度预测值2.189 86Abs接近。通过铁盐催化比色法HPLC法分析并得出荔枝皮黄烷-3-醇类成份及含量:原花青素、没食子酸、表没食子儿茶素、儿茶素、表儿茶素和表儿茶素没食子酸酯分别为89.32,1.11,87.09,3.37,31.15,7.02mg/g。     

高压静电场对采后葡萄果实总黄烷-3-醇及隐色花色素还原酶表达的影响

目的:阐明葡萄果实采后用高压静电场(HVEF)处理对总黄烷-3-醇含量和隐色花色素还原酶(LAR)表达的影响。方法:赤霞珠葡萄成熟果实经-2 kV/cm高压静电场处理,分别于30,60,120,240 min取样,采用分光光度计法、蛋白质印迹法和实时荧光定量PCR对果实中超氧化物歧化酶(SOD)活性、丙二醛(MDA)、总酚、黄烷醇类多酚、总黄烷-3-醇含量及其LAR表达进行分析,从底物、酶活性、酶蛋白含量及基因转录水平揭示HVEF对Vv lar1、Vv lar2表达的影响。结果:HVEF诱导葡萄果实中SOD活性增强,抑制果实中MDA的积累;诱导果实中总黄烷-3-醇含量增加,而对总酚、黄烷醇类多酚含量无明显作用。HVEF处理60 min后,LAR酶活性明显增强。蛋白质印迹法结果表明,HVEF明显诱导LAR1、LAR2新蛋白的合成,特别是在处理后30 min和60 min。实时荧光定量PCR结果表明,HVEF处理后30~60 min,Vv lar1、Vv lar2表达明显增强。结论:HVEF诱导Vv lar1、Vv lar2表达,LAR1、LAR2新蛋白合成,LAR酶活性增强,从而导致葡萄果实中总黄烷-3-醇积累。     

苹果酒酚类物质研究进展

苹果酒中含有多种酚类物质,主要是酚酸类和类黄酮类化合物,酚酸类包括绿原酸、原儿茶酸和p-香豆酸等,类黄酮类主要是黄烷-3-醇类,包括儿茶素、表儿茶素等.这些成分对苹果酒的风味、颜色和质量起着重要作用.综述了苹果酒中的酚类化合物及其作用机理,并简要介绍了酚类物质的测定方法.     

Insights into the metabolism and microbial biotransformation of dietary flavan-3-ols and the bioactivity of their metabolites

Flavan-3-ols, occurring in monomeric, as well as in oligomeric and polymeric forms (also known as condensed tannins or proanthocyanidins), are among the most abundant and bioactive dietary polyphenols, but their in vivo health effects in humans may be limited because of their recognition as xenobiotics. Bioavailability of flavan-3-ols is largely influenced by their degree of polymerization; while monomers are readily absorbed in the small intestine, oligomers and polymers need to be biotransformed by the colonic microbiota before absorption. Therefore, phenolic metabolites, rather than the original high molecular weight compounds found in foods, may be responsible for the health effects derived from flavan-3-ol consumption. Flavan-3-ol phenolic metabolites differ in structure, amount and excretion site. Phase II or tissular metabolites derived from the small intestine and hepatic metabolism are presented as conjugated derivatives (glucuronic acid or sulfate esters, methyl ether, or their combined forms) of monomeric flavan-3-ols and are preferentially eliminated in the bile, whereas microbial metabolites are rather simple conjugated lactones and phenolic acids that are largely excreted in urine. Although the colon is seen as an important organ for the metabolism of flavan-3-ols, the microbial catabolic pathways of these compounds are still under consideration, partly due to the lack of identification of bacteria with such capacity. Studies performed with synthesized or isolated phase II conjugated metabolites have revealed that they could have an effect beyond their antioxidant properties, by interacting with signalling pathways implicated in important processes involved in the development of diseases, among other bioactivities. However, the biological properties of microbe-derived metabolites in their actual conjugated forms remain largely unknown. Currently, there is an increasing interest in their effects on intestinal infections, inflammatory intestinal diseases and overall gut health. The present review will give an insight into the metabolism and microbial biotransformation of flavan-3-ols, including tentative catabolic pathways and aspects related to the identification of bacteria with the ability to catabolize these kinds of polyphenols. Also, the in vitro bioactivities of phase II and microbial phenolic metabolites will be covered in detail.     

Bioavailability and metabolism of flavonoids

In the review the modern data about bioavailability and a metabolism of flavonoids is considered. The data about absorption flavonoids in a digestive path, participation of microorganisms in their hydrolysis, pharmacokinetic the data on the basic classes flavonoids: flavanes (flavan-3-ols), anthocyanes, flavones, flavonols and flavanones is cited.     

原花色素降血脂机制研究进展

原花色素是以黄烷-3-醇为基本单元,在自然界中广泛存在的多酚类物质,具有多种生物活性。本文综述了原花色素如何调节甘油三酯和胆固醇代谢过程中的关键蛋白从而控制体内主要脂类的含量;此外,还总结了原花色素如何调节体质量、能量摄入以及通过调节AMP依赖蛋白激酶（adenosine 5’-monophosphate-activated proteinkinase,AMPK）信号通路影响能量消耗,进而综合调控体内血脂的含量,达到降低血脂的功能。     

Flavan-3-ols: nature, occurrence and biological activity

Representing the most common flavonoid consumed in the American diet, the flavan-3-ols and their polymeric condensation products, the proanthocyanidins, are regarded as functional ingredients in various beverages, whole and processed foods, herbal remedies and supplements. Their presence in food affects food quality parameters such as astringency, bitterness, sourness, sweetness, salivary viscosity, aroma, and color formation. The ability of flavan-3-ols to aid food functionality has also been established in terms of microbial stability, foamability, oxidative stability, and heat stability. While some foods only contain monomeric flavan-3-ols [(-)-epicatechin predominates] and dimeric proanthocyanidins, most foods contain oligomers of degree of polymerization values ranging from 1-10 or greater than 10. Flavan-3-ols have been reported to exhibit several health beneficial effects by acting as antioxidant, anticarcinogen, cardiopreventive, antimicrobial, anti-viral, and neuro-protective agents. This review summarizes the distribution and health effects of these compounds.     

Identification and bioactivity evaluation of flavan-3-ols in the milk of dairy sheep fed Cynomorium songaricum

Cynomorium songaricum is a traditional medicine and also a food material that is eaten raw or processed as tea or beverages. As a featured plant in semi-desert grasslands, C. songaricum is also eaten by the cattle and sheep in the area. This research study fed dairy sheep C. songaricum to determine the flavan-3-ols in sheep milk. Catechin (Cat), epicatechin (Epi), procyanidin A1 (A1), procyanidin A2 (A2), and procyanidin B1 (B1) were detected in sheep milk with the concentration being Epi > A2 > Cat > B1 > A1 at 24 h after the administration of C. songaricum. Neither A1 nor A2 were detected in the methanol extract of C. songaricum. Cysteine degradation of the plant revealed that in addition to Epi, A2 was the extending unit of the polymeric flavan-3-ols in C. songaricum, indicating that A2 is released digestively from the polymers and enters the milk. Procyanidin B-1 was converted to A1 on incubation in raw but not heated milk, indicating that the A1 in milk is the enzymatically transformed product of B1. Accelerated oxidation showed that the flavan-3-ols, B1, Cat, and Epi significantly protects the unsaturated triacyglycerols in the milk from oxidation. The flavan-3-ol could slow down the oxidation of glutathione and the latter may play an important role in preventing the milk triglycerides from oxidation. Flavan-3-ols are polyphenols with many health benefits. The present research revealed the antioxidant activities of flavan-3-ols that could be absorbed to sheep milk, adding new evidences for the values of these flavan-3-ols and for the milk.     

Cocoa polyphenols are absorbed in Caco-2 cell model of intestinal epithelium

Cocoa is an abundant source of polyphenols, mainly flavan-3-ol monomers and polymers. In the literature, there are contradictory data on the absorption limit of procyanidins in humans. In our study, the Caco-2 cell model of intestinal epithelium was used to determine the absorption and secretion of cocoa flavan-3-ols. Three compounds: (+)-catechin, (-)-epicatechin and procyanidin B2 were detected and quantified at the receiver side of Caco-2 monolayer after 2h transport experiment. The obtained results of apparent permeability coefficient suggest paracellular route of transport of investigated compounds. Additionally, the results suggest that compounds of cocoa powder purified extract are able to affect tight junction functioning.     

Effect of frozen storage on the phenolic content of vacuum impregnated Granny Smith and Stark Delicious apple <Emphasis Type="Italic">cvv</Emphasis>.

The phenolic fraction modification was evaluated in untreated vacuum impregnated frozen apple slices from two varieties (Granny Smith and Stark Delicious) a few days after freezing and after 12 months of frozen storage. After 12 months the phenolic content of both fresh and vacuum impregnated apple slices varied greatly. The most important change was the increase of many polymeric flavan-3-ols, which may be due to hydrolysis of polymeric procyanidins. Furthermore, there was significant correlation (r ² = 0.52, P < 0.05) between the increase in flavan-3-ols and the decrease in pH. In fact, control Stark slices presented the highest pH, and had no statistically significant increase in flavan-3-ols. Other classes of phenolic compounds were decreased in apple slices following frozen storage.     

Phenolic constituents in major fractions of tropical rapeseed

Phenolic constituents in major fractions such as seed, cotylendons and hulls of commercial rapeseed varieties Ganyou-5, Westar, Raya-brown and Raya yellow grown under tropical conditions in Pakistan, were determined. Quantitative determination in percentage of sinapine, catechin, tannic acid and total phenolics as well as in absorption units at 550 nm of procyanidine, proanthocyanidine and flavan-4-ols in relation to different extractants such as methanol, methanol-HCl and their totals, were made. These varieties and their fractions widely varied in different phenolic constituents in respect of extractants used. Hulls of all cultivars contained higher levels of catechin, procyanidine, pronanthocyanidine and flavan-4-ols while lower amounts of sinapine, tannic acid and total phenols than the cotylendons. Cotylendons and hulls in seeds of raya-brown were exceptionally high in procyanidine.     

Oligomeric procyanidins inhibit cell migration and modulate the expression of migration and proliferation associated genes in human umbilical vascular endothelial cells

The consumption of flavan-3-ols has been associated with reduced risk of cardiovascular diseases and improvements in vascular function. However, the nature of the flavan-3-ols responsible and the mechanisms underlying the vascular responses are not fully understood. We used microarrays to search for molecular changes in response to the exposure to (-)-epicatechin (EC), procyanidin dimer B2, and a mixture of oligomeric procyanidins in human umbilical vein endothelial cells (HUVECs). No gene expression changes were detected in HUVECs exposed to EC or dimer B2, however, the oligomeric procyanidins induced significant gene expression changes in both resting and TNF-alpha-stimulated cells. In particular, the expression of genes such as ADAMTS1, THBS1, ANGPT2, CYR61, ET-1, EDG3, and PDE4B involved in endothelial cell migration and proliferation, were substantially over-represented. Also, exposure to the oligomers arrested the cells at the G(0)/G(1 )phase and inhibited cell migration. These data show that human endothelial cells respond to oligomeric procyanidins by exhibiting a less migratory phenotype and by a general modulation of the expression of genes that are associated with key events in the angiogenic process. The molecular changes associated with procyanidin treatment identified in this study are consistent with the beneficial effects of flavan-3-ols on vascular function.     

Determination of free radicals and flavan-3-ols content in fermented and unfermented teas and properties of their infusions

The objective of this study was to analyse selected brands of fermented (red and black) and unfermented (white and green) teas for free radical content with the use of electron paramagnetic resonance (EPR) spectroscopy and for contents of flavan-3-ols by means of high-performance liquid chromatography. Analyses were also conducted for the polyphenolic profile of infusions of the analysed teas (with the Folin–Ciocalteu’s method) and their antioxidant activity (in reaction with a DPPH radical) at three brewing times (5, 10 and 15 min). The obtained results showed the possibility of using rapid spectroscopic method EPR to evaluate the oxidative changes in tea leaves caused by enzymatic fermentation. The number of free radicals in teas was negatively correlated with contents of flavan-3-ols, (?)-EGCG in particular. The main signals observed in EPR spectra of teas were attributed to semiquinone radicals; however, also signals attributed to carbohydrate radicals were detected. Regarding unfermented teas, it was ascertained that teas with the highest content of flavan-3-ols, (?)-EGCG in particular, were characterised by the lowest content of semiquinone radicals and a high content of carbohydrate radicals. The group of fermented teas demonstrated to contain mainly semiquinone radicals. The total phenolic content and antioxidant activity of the tea infusions were strongly diversified depending on the kind and brand of tea as well as on the extraction time. The predominating flavan-3-ol in the analysed teas was epigallocatechin gallate (?)-EGCG, the content of which was additionally highly correlated with the antioxidant activity of the tea infusions.