植物雌激素研究概况(Ⅱ)——生理功能进展

综述了植物雌激素（包括大豆异黄酮、木酚素以及二苯乙烯）的作用机制：（1）雌激素受体（ER）相关作用，主要表现为雌激素或抗雌激素效果；（2）与一些合成性类甾醇的主要酶相互作用（间接显示雌激素活性）；（3）其它非荷尔蒙作用。还综述了植物雌激素对人类健康的潜在效果，包括调节月经周期、预防并抑制许多癌症、预防心血管疾病以及骨疏松症，还有抗氧化效果以及女性美容效果。     

植物果蔬发酵液对S180荷瘤小鼠抗肿瘤作用研究

研究植物果蔬发酵液对S180荷瘤小鼠的肿瘤抑制作用,探讨植物果蔬发酵液抑制肿瘤的作用机制。采用S180细胞接种KM小鼠构建荷瘤模型,并灌胃植物果蔬发酵液。通过试剂盒进行甘油三酯、胆固醇以及抗氧化活性等的测定。采用MTT法测定脾细胞增值率,LDH法测定NK细胞活性。低中高剂量植物果蔬发酵液对肿瘤的抑制率分别为18.2%、25.5%和52.7%。不同剂量的发酵液对NK细胞活性、血清总胆固醇和体重无显著影响,但具有提高T细胞活性的趋势。此外,高剂量的植物果蔬发酵液能显著降低甘油三酯水平和肝脏指数(P0.05),抗氧化试验结果表明低、高剂量发酵液能增强T-SOD活性。植物果蔬发酵液可能通过改善机体免疫和抗氧化能力发挥抗肿瘤作用,具体机制还需要深入研究。     

染料木黄酮生理功能的研究进展

染料木黄酮是苷元形式的大豆异黄酮，是大豆异黄酮中的一种主要活性组分，具有多种生物活性。本文简述了染料木黄酮的植物雌激素功能、预防骨质疏松症、抗癌作用、预防和治疗皮肤疾病等多种生理功能。     

植物木酚素生物转化研究进展

植物雌激素是植物中发现或源自植物前体的弱雌激素,在结构上与内源性雌激素相似,同时具有雌激素作用和抗雌激素作用。木酚素是一种植物雌激素,存在于亚麻籽等种子、蔬菜、水果、饮料等日常食品中。膳食木酚素及其衍生代谢物有抗氧化、抗恶性细胞增生等功能,可预防乳腺癌和前列腺癌,心血管疾病,糖尿病等。膳食木酚素生物利用度低,必须被肠道菌群转化为哺乳动物木酚素,如肠二醇和肠内酯,才能发挥其有益作用,膳食木酚素的转化是由人类肠道内优势菌群和亚优势菌群的作用造成的。因此,体外转化膳食木酚素可以提高其生物利用度。比起化学合成法,生物转化法是从膳食木酚素中大量生产哺乳动物木酚素,是一种非常经济、高效和环保的方法。该文简述了木酚素的结构、种类和分布,探讨了木酚素肠道微生物代谢机制,对体外木酚素微生物和酶法转化的研究进展进行了综述。     

香叶木苷抗肿瘤作用及机制的研究进展

香叶木苷又名地奥司明(Diosmin),在多种药食同源的天然植物中含量丰富,其作用于动静脉系统的药理学活性被广泛报道,其可抑制肿瘤细胞增殖,对癌细胞具有特异性促凋亡活性和化学预防作用,因而被认为是有潜质的抗肿瘤药物。本文将香叶木苷对肿瘤细胞的增殖与凋亡、信号通路、抗多药耐药等方面的机制作以综述。     

食源性黄酮类化合物对肝脏功能的影响与作用机制研究进展

黄酮类化合物作为促进健康,预防疾病的膳食补充剂,具有抗氧化作用、抗炎、预防癌症等活性。由于它们的低毒性与高安全性,使其成为化学预防剂的最佳候选者。黄酮类化合物在对肝脏功能的影响方面,具有抗肝炎、抗肝纤维化、抗肝癌、改善肝脂质代谢、调节肝脏免疫功能等作用,其机制与抗氧化作用、抑制肿瘤坏死因子、调节细胞凋亡等相关。为了合理利用我国丰富的植物资源,更加深入研究食源性黄酮类化合物的保肝功能与作用机制以及更好地开发食源性黄酮类保健品,文中综述了近年来国内外对食源性黄酮类化合物保肝功能及其作用机制的研究进展。     

植物雌激素的研究进展

植物雌激素具有广泛的健康效应。本文就植物雌激素的化学特性、代谢分布及作用机制进行了简述。     

蔷薇科火棘属和蔷薇属植物研究进展

火棘属和蔷薇属植物主要含挥发油及三萜、黄酮、鞣质、多糖、皂苷以及氨基酸等化学成分,具有酪氨酸酶抑制活性、抗氧化活性、免疫调节和预防肿瘤等作用。通过对火棘及蔷薇属植物的化学成分、活性及应用研究综述,以期为进一步研究和开发提供参考。     

亚麻木酚素对动脉粥样硬化的改善作用研究进展

木酚素是一种植物雌激素,存在于多种植物中,亚麻籽中含量最高。研究表明亚麻木酚素具有降低血脂、预防心血管疾病、抗氧化、抗癌、抗炎以及抗动脉粥样硬化(AS)等多种生理功能。虽然关于其抗AS的作用已有相关报道,但具体机制还有待进一步研究。AS是发生于动脉的多发性、慢性、炎症性疾病。目前关于其发病的确切机制尚不明确,但有研究表明高血脂、高血压、高血糖、氧化应激以及炎症反应等都是AS的危险因素。主要对亚麻木酚素对AS的改善作用进行综述,以期为亚麻木酚素功能性食品的研究开发提供借鉴。     

几种常见植物多酚降血脂作用及机制研究进展

植物多酚具有许多生物活性,是近年来食品科学热点研究领域之一。本文综述几种常见的果蔬多酚,如石榴多酚、茶多酚、葡萄多酚、苹果多酚、山楂多酚等在降血脂及预防心脑血管疾病等方面的生物学活性及作用机制,并列出这几种多酚的主要活性成分,比较其降脂作用及机制的异同。     

Variability of phytoestrogen content in foods from different sources

Phytoestrogens are a group of non-steroidal polyphenolic plant metabolites and can mimic or modulate the action of endogenous estrogens. Phytoestrogens are considered to be beneficial for a variety of conditions, for example hormone-related cancers like breast and prostate cancer; however, epidemiological data are inconclusive and more information on exposure is required. To assess the exposure of larger cohorts or the general public, reliable data on the phytoestrogen content of food is necessary, however, this is made difficult by the variability of phytoestrogen content depending on variety, environmental factors, growth, harvesting and processing. Only limited data is available and most investigations have been conducted on soya beans in which a fourfold variation has been found. We have analysed nine different types of foods from different sources and countries of origin for their phytoestrogen content. The average detected range of phytoestrogen content between samples was threefold (95% confidence interval: 2.4; 3.4) with an average CV for isoflavones of 37% and lignans of 33%.     

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.     

植物性食品中雌激素的化学结构和生理活性及在功能食品中的应用

异黄酮(isoflavone)、木脂素(lignan)和香豆雌酚(coumestrol)等多酚类雌激素,是大豆、芝麻、大米、水果和蔬菜等食品特有的天然生理活性成分,具有重要的生理功能和健康效应。作为食品的功能因子,具有广阔的应用前景。植物雌激素的化学结构、生物活性、作用机理及抗癌效应的研究受到普遍关注,成为功能食品研究的新的生长点。本文综述了植物雌激素的测定方法、结构与生理活性、生物学功能等最新研究进展,并提出了雌激素在功能食品生产的应用前景。     

Reproductive consequences of developmental phytoestrogen exposure

Phytoestrogens, estrogenic compounds derived from plants, are ubiquitous in human and animal diets. These chemicals are generally much less potent than estradiol but act via similar mechanisms. The most common source of phytoestrogen exposure to humans is soybean-derived foods that are rich in the isoflavones genistein and daidzein. These isoflavones are also found at relatively high levels in soy-based infant formulas. Phytoestrogens have been promoted as healthy alternatives to synthetic estrogens and are found in many dietary supplements. The aim of this review is to examine the evidence that phytoestrogen exposure, particularly in the developmentally sensitive periods of life, has consequences for future reproductive health.     

Phytoestrogen content of fruits and vegetables commonly consumed in the UK based on LC–MS and C-labelled standards

Phytoestrogens are a group of non-steroidal secondary plant metabolites with structural and functional similarity to 17β-oestradiol. Urinary and plasma phytoestrogens have been used as biomarkers for dietary intake, however, this is often not possible in large epidemiological studies or to assess general exposure in free-living individuals. Accurate information about dietary phytoestrogens is therefore important but there is very limited data concerning food contents. In this study, we analysed the phytoestrogen (isoflavone, lignan and coumestrol) content in more than 240 different foods based on fresh and processed fruits and vegetables using a newly developed sensitive method based on LC–MS incorporating ¹³C₃-labelled standards. Phytoestrogens were detected in all foods analysed with a median content of 20 μg/100 g wet weight (isoflavones: 2 μg/100 g; lignans 12 μg/100 g). Most foods contained less than 100 μg/100 g, however, 5% of foods analysed contained more than 400 μg/100 g, in particular soya-based foods and other legumes. The results published here will contribute to databases of dietary phytoestrogen content and allow the more accurate determination of phytoestrogen exposure in free-living individuals.     

Bacterial metabolism as responsible of beneficial effects of phytoestrogens on human health

Abstract

Phytoestrogens (PE) are compounds found in plants such as soy (isoflavones), flax seeds and cereals (lignans) and pomegranates (ellagitannins). PE have shown estrogenic/antiestrogenic, antioxidant, anti-inflammatory, antineoplastic and apoptotic activities. The human studies are showing promising although inconsistent results about the beneficial effects of PE on ameliorating the menopausal symptoms or reducing the risk of certain cancers, cardiovascular disease or diabetes. The effects of PE on the organism are mediated by the intestinal microbiota, which transforms them into bioactive PE such as genistein, equol, enterolignans and certain urolithins. In this work, we review the most recent findings about the bacteria able to metabolize PE, together with the latest studies on the effects of PE on health. In addition, we describe the possible factors hindering the demonstration of the beneficial effect of PE on health, evincing the importance of measuring the actual circulating PE in order to encompass the variability of PE metabolism due to the intestinal microbiota. With this in mind, we also explore an approach to ensure the access to bioactive PE.     

Assessment of the estrogenicity of the diet of a healthy female Spanish population based on its isoflavone content

Phytoestrogens are natural components of plants consumed by humans. The hormonal activity of these substances has long been known. Various in vitro tests have demonstrated the agonistic or antagonistic estrogenic activity of some phytoestrogens. The objective of this study was to estimate the supply of isoflavones in the diet of a healthy adult female population and to assess its estrogenic effect. The diet was assessed by questionnaire and the estrogenicity of the estimated isoflavone content was tested by E-screen, finding a mean total estrogenic capacity of 0.129 × 10^?10 eq.E₂ (12.9 pmol day^–1), corresponding to a daily isoflavone intake of 265.8 μg day^–1. This study offers a preliminary insight into the phytoestrogen content of the diet of a healthy active population of Spanish women. The effects of this additional hormonal burden are highly controversial, and this approach to estimating dietary phytoestrogen intake of specific populations may help to elucidate its implications for human health.     

Nutritional factors and colon cancer

During the last 2 decades, substantial progress has been made in understanding the relationship between dietary constituents and the development of colon cancer in man. Unlike studies of cancer among smokers and nonsmokers, nutritional epidemiologic studies are confronted with the inherent difficulty of assessing reasonably precise exposures. The lack of consistency between international correlation studies and case‐control studies does not necessarily negate a dietary etiology of colon cancer because these inconsistencies may have arisen, at least in part, from methodological limitations. Some of these deficiencies in epidemiological studies of diet and cancer have been corrected; recent case‐control studies demonstrated that high dietary fat is a risk factor for colon cancer development and that an overall increase in intake of foods high in fiber might decrease the risk for colon cancer. The results of epidemiologic studies may be assumed to present conservative estimates of the true risk for cancer associated with diet. The populations with high incidences of colon cancer are characterized by high consumption of dietary fat, which may be a risk factor in the absence of factors that are protective, such as whole‐grain cereals and of other high fiber. Laboratory‐animal model studies have shown that certain dietary lipids and fibers influence tumorigenesis in the colon. The data of metabolic epidemiological and laboratory‐animal model studies are sufficiently convincing with respect to the enhancement of colon cancer by type of fat and protection by certain dietary fibers.     

支链脂肪酸的来源与功能研究进展

支链脂肪酸主要包括单支链脂肪酸和多支链脂肪酸,多存在于人体皮肤及其分泌物、微生物细胞膜、乳制品及肉制品中。近年来的研究表明,支链脂肪酸对乳腺癌细胞、前列腺癌细胞和膀胱癌细胞等具有潜在抑制作用,此外,支链脂肪酸还有抑制新生儿坏死性小肠结肠炎发病率等抗炎作用。进一步对各种食物以及人体各组织中的支链脂肪酸进行检测分析,并对支链脂肪酸结构功能与作用机理进行深入研究,是目前支链脂肪酸研究的重要方向。     

Pharmacological Intervention through Dietary Nutraceuticals in Gastrointestinal Neoplasia

Neoplastic conditions associated with gastrointestinal (GI) tract are common worldwide with colorectal cancer alone accounting for the third leading rate of cancer incidence. Other GI malignancies such as esophageal carcinoma have shown an increasing trend in the last few years. The poor survival statistics of these fatal cancer diseases highlight the need for multiple alternative treatment options along with effective prophylactic strategies. Worldwide geographical variation in cancer incidence indicates a correlation between dietary habits and cancer risk. Epidemiological studies have suggested that populations with high intake of certain dietary agents in their regular meals have lower cancer rates. Thus, an impressive embodiment of evidence supports the concept that dietary factors are key modulators of cancer including those of GI origin. Preclinical studies on animal models of carcinogenesis have reflected the pharmacological significance of certain dietary agents called as nutraceuticals in the chemoprevention of GI neoplasia. These include stilbenes (from red grapes and red wine), isoflavones (from soy), carotenoids (from tomatoes), curcuminoids (from spice turmeric), catechins (from green tea), and various other small plant metabolites (from fruits, vegetables, and cereals). Pleiotropic action mechanisms have been reported for these diet-derived chemopreventive agents to retard, block, or reverse carcinogenesis. This review presents a prophylactic approach to primary prevention of GI cancers by highlighting the translational potential of plant-derived nutraceuticals from epidemiological, laboratory, and clinical studies, for the better management of these cancers through consumption of nutraceutical rich diets and their intervention in cancer therapeutics.