057 白藜芦醇的生物学作用

白藜芦醇是一类主要存在于葡萄及葡萄制品中的、具有重要活性的植物化合物。本文对白藜芦醇的体内代谢及其主要生物学作用(抗癌作用、抗动脉粥样硬化作用、雌激素样作用以及对骨代谢的影响)进行综述。     

白藜芦醇的生物学作用

白藜芦醇是一类主要存在于葡萄及葡萄制品中的、具有重要活性的植物化合物。本对白藜芦醇的体内代谢及其主要生物学作用（抗癌作用、抗动脉粥样硬化作用、雌激素样作用以及对骨代谢的影响）进行综述。     

姜黄素抗肺纤维化作用及机制研究进展

姜黄素是姜黄属植物根茎中分离出来一种多酚类化合物,也是中药姜黄发挥药理作用的主要成分,具有抗肿瘤、抗氧化、抗炎、抗纤维化等广谱的药理活性。近年来学者们系统深入地研究了姜黄素抗肺纤维化作用,文章归纳总结了姜黄素抗肺纤维化作用的研究概况,为其进一步的实验及临床研究提供理论参考。     

纽崔莱·新知

抗氧化营养物质的间接作用 清除多余的自由基（包括活性氧和活性氮等）是抗氧化物质抵御衰老的一个重要作用机制。近年研究显示,部分植物化合物还可通过其他机制间接促进机体的抗氧化防御体系,如对一系列抗氧化酶物质的活性和合成水平等进行调节。     

体内自由基清除剂及抗氧化剂—原花青素的研究进展

原花青素(Procyanidins,PC)是植物黄酮中的一大类多酚化合物的总称。从1961年德国Karl等首次从山植中分离出2种多酚化合物开始,对原花青素的研究已有近40年的历史,特别是从20世纪80年代以来,国外对多种植物尤其是葡萄中的各种原花青素进行了广泛深入研究,证实了其优越的抗氧化活性、酶抑制活性、血管保护活性、抗炎活性、抗肿瘤活性等,并在药品、保健品和化妆品中广泛应用,是极具发展前景的天然植物提取物。     

中药降血脂类有效成分——植物甾醇的含量及分布研究

<正>植物甾醇(phytosterol,plant sterol)是植物性原料中的一大类植物化合物,其化学结构与胆固醇非常相似,是3位羟基的甾体化合物,以环戊烷全氢菲为主体骨架,占四环三萜类化合物的大部分。目前已发现的植物甾醇已有百余种,其中最常见的是β-谷甾醇(β-sitosterol)、菜油甾醇(campesterol)、豆甾醇(stigmasterol)和谷甾烷醇(sitostanol)。研究发现,植物甾醇具有多种生理功能和作用,如:降血脂功能[1]、抗氧化功     

植物精油对吸血节肢动物的驱避活性

当前,化学合成药剂对昆虫和节肢动物的防治已引起环境的污染和威胁人类健康,而天然源产物具有良好的杀虫活性和环境安全性.作为一种有价值的天然源,从不同植物中提取的精油已广泛用于驱避试验,在有开发前景的精油作为驱避剂的植物中,香茅属、罗勒属和桉树属应用最为广泛.该文着重从植物精油对吸血节肢动物的驱避活性,植物精油中的成分和驱避活性之间的相关性及植物精油对驱避的增效作用等方面做一综述.     

3-羟基异黄酮对卵巢癌的防治作用

3-羟基异黄酮(genistein)属于异黄酮化合物,为一弱植物雌激素,在肿瘤的发生、发展阶段存在着多重抑制效应,其抗肿瘤机制为调节雌激素受体、抑制酪氨酸蛋白激酶活性、抑制血管形成、增强抗氧化酶的活性、调节细胞周期、诱导细胞凋亡、抑制拓扑异构酶的活性等,与多种肿瘤的发生低风险有关。3-羟基异黄酮也可作为一种辅助治疗药物,提高肿瘤细胞对放疗的敏感性,增强化疗药物的抗肿瘤作用,降低肿瘤的复发及转移。综述3-羟基异黄酮抗肿瘤作用机制及其在卵巢癌中的研究。     

大蒜对糖尿病大鼠的抗过氧化作用

大蒜是百合科葱属植物的磷茎,含有多种抗氧化的活性成分如含硫化合物,微量元素硒、锗、锌等以及维生素Ｂ1和维生素Ｃ等,其药用价值历史悠久,自从70年代初Ｃｈｏｐｒａ首次报道了大蒜素对正常家兔有降低血糖作用以来,国内外一些研究证实了大蒜及其提取物对糖尿病动物的血糖亦有降低作用〔1〕。许多研究证实,实验性糖尿病的发病与氧自由基反应增强和抗氧自由基酶类活性降低有密切关系〔2〕,同时发现糖尿病人血清脂质过氧化物(ＬＰＯ)含量升高,抗过氧化酶活性降低〔3〕。在本次实验中,我们观察了大蒜制剂对实验性糖尿病大鼠体内脂质过氧化物及…     

氨基甲酸酯类卫生杀虫剂的应用

1 简述 氨基甲酸酯类卫生杀虫剂自20世纪50年代问世以来,在短短的二十几年就发展成为与有机磷类、拟除虫菊酯类杀虫剂并驾齐驱的三大类农药之一。这对有机磷、拟除虫菊酯类杀虫剂的抗性以及轮换、交替使用起了重要的作用。 这类化合物对昆虫多数都具有触杀和胃毒作用,有的还兼有熏蒸和内吸作用,他们速效性好,选择性强,残留低,残效期长。 与有机磷杀虫剂一样,它的作用机理是抑制胆碱酯酶的活性,使昆虫不能分解乙酰胆碱,使昆虫的     

Phytochemicals and cancer

Epidemiological studies showing a protective effect of diets rich in fruits and vegetables against cancer have focused attention on the possibility that biologically-active plant secondary metabolites exert anti-carcinogenic activity. This huge group of compounds, now collectively termed 'phytochemicals', provides much of the flavour and colour of edible plants and the beverages derived from them. Many of these compounds also exert anti-carcinogenic effects in animal models of cancer, and much progress has been made in defining their many biological activities at the molecular level. Such mechanisms include the detoxification and enhanced excretion of carcinogens, the suppression of inflammatory processes such as cyclooxygenase-2 expression, inhibition of mitosis and the induction of apoptosis at various stages in the progression and promotion of cancer. However, much of the research on phytochemicals has been conducted in vitro, with little regard to the bioavailability and metabolism of the compounds studied. Many phytochemicals present in plant foods are poorly absorbed by human subjects, and this fraction usually undergoes metabolism and rapid excretion. Some compounds that do exert anti-carcinogenic effects at realistic doses may contribute to the putative benefits of plant foods such as berries, brassica vegetables and tea, but further research with human subjects is required to fully confirm and quantify such benefits. Chemoprevention using pharmacological doses of isolated compounds, or the development of 'customised' vegetables, may prove valuable but such strategies require a full risk-benefit analysis based on a thorough understanding of the long-term biological effects of what are often surprisingly active compounds.     

Bitter taste, phytonutrients, and the consumer: a review

Dietary phytonutrients found in vegetables and fruit appear to lower the risk of cancer and cardiovascular disease. Studies on the mechanisms of chemoprotection have focused on the biological activity of plant-based phenols and polyphenols, flavonoids, isoflavones, terpenes, and glucosinolates. Enhancing the phytonutrient content of plant foods through selective breeding or genetic improvement is a potent dietary option for disease prevention. However, most, if not all, of these bioactive compounds are bitter, acrid, or astringent and therefore aversive to the consumer. Some have long been viewed as plant-based toxins. As a result, the food industry routinely removes these compounds from plant foods through selective breeding and a variety of debittering processes. This poses a dilemma for the designers of functional foods because increasing the content of bitter phytonutrients for health may be wholly incompatible with consumer acceptance. Studies on phytonutrients and health ought to take sensory factors and food preferences into account.     

The Renaissance of Plant Mucilage in Health Promotion and Industrial Applications: A Review

Plant mucilage is a renewable and cost-effective source of plant-based compounds that are biologically active, biodegradable, biocompatible, nontoxic, and environmentally friendly. Until recently, plant mucilage has been of interest mostly for technological purposes. This review examined both its traditional uses and potential modern applications in a new generation of health-promoting foods, as well as in cosmetics and biomaterials. We explored the nutritional, phytochemical, and pharmacological richness of plant mucilage, with a particular focus on its biological activity. We also highlighted areas where more research is needed in order to understand the full commercial potential of plant mucilage.     

Gastrointestinal physiology and functions

While the health benefit of a functional food may be a metabolic response that lowers risk for disease, the actual target for the food or food component may be on the functioning of the gastrointestinal tract (GIT). For example, slowing absorption from the intestine, as measured by examining the appearance of the nutrient or food component in the blood, the hormone response associated with absorption of the compound or excretion of the compound, may provide a health benefit. However, the food component may slow absorption by delaying gastric emptying, altering the mixing within the intestinal contents or decreasing the availability of digestive enzymes in the intestine. These measures of GIT function provide validation of the mechanisms by which the functional food or food components affect metabolism. Bioavailability of physiologically active compounds from foods will be determined by the digestibility of foods that contain these compounds, their subsequent absorption and utilization by tissues. The physical structure of foods contributes to the functional effects of foods as well as to the availability of compounds from foods. For example, recent studies have demonstrated that changing the viscosity of the gut contents alters absorption and GIT response. Additionally, food structures such as the plant cell wall change the availability of absorbable compounds along the gastrointestinal contents. The areas of probiotics and prebiotics have highlighted the potential importance of gut microflora in health. While evidence suggests biological activity relevant to disease risk reduction, the long-term implications of the microbial activity have yet to be established.     

Bioavailability, antioxidant and biological properties of the natural free-radical scavengers cyanidin and related glycosides

Cyanidin and its glycosides (Cy and Cyg) have been indicated as promising candidates as dietary compounds with a potential role in human health. They are the largest class of water-soluble compounds in plants, where they are responsible for the brilliant color (red, orange, blue) of fruits and flowers. As natural compounds of several foods such as vegetables, fruits and red wines, they are estimated to be widely ingested by humans. This paper, basing on the data previously reviewed in 2002, focuses on the findings regarding human and animal studies on Cy and Cyg absorption and metabolism, antioxidant activity and biological properties, with particular attention to anticarcinogenic activity, vasoprotective, anti-inflammatory, anti-obesity and anti-diabetes effects. It is concluded that although Cy and Cyg bioavailability is low, further investigations are necessary because some important metabolites may still not have been identified. Literature data on antioxidant activity and biological properties, however, widely confirm Cy and Cyg as dietary compounds with a potential beneficial role in human health.     

Synthesis, molecular modeling and biological evaluation of chalcone thiosemicarbazide derivatives as novel anticancer agents

A series of novel chalcone thiosemicarbazide derivatives (4a-4x) have been designed, synthesized, structurally determined, and their biological activities were also evaluated as potential EGFR kinase inhibitors. All the synthesized compounds are first reported. Among the compounds, compound 4r showed the most potent biological activity (IC(50) = 0.78 ± 0.05 μM for HepG2 and IC(50) = 0.35 μM for EGFR), which is comparable to the positive controls. Docking simulation was also performed to position compound 4r into the EGFR active site to determine the probable binding model. Antiproliferative assay results demonstrated that some of these compounds possessed good antiproliferative activity against HepG2. Compound 4r with potent inhibitory activity in tumor growth inhibition may be a potential anticancer agent.     

锗元素与抗肿瘤药物(Ⅱ)(续上期)

综述了有机锗抗肿瘤药物，对β－羧乙基锗倍半氧化物（Ｇｅ－１３２）和螺锗在肿瘤学中的作用以及抗癌效应机制作出评价。自８０年代起至今，又有含硫杂、柠檬酸、氨基酸、苯基的锗化合物，以及锗酵母、含锗中草药等被先后合成出来。在几类具有生物活性的有机锗化合物中，仍首推Ｇｅ－１３２，螺锗及其衍生物为低毒有效抗肿瘤候选药物，然而对于锗导致的毒性及其机理仍需进一步加以探讨。     

The strawberry: composition, nutritional quality, and impact on human health

Strawberries are a common and important fruit in the Mediterranean diet because of their high content of essential nutrients and beneficial phytochemicals, which seem to have relevant biological activity in human health. Among these phytochemicals, anthocyanin and ellagitannins are the major antioxidant compounds. Although individual phytochemical constituents of strawberries have been studied for their biological activities, human intervention studies using whole fruits are still lacking. Here, the nutritional contribution and phytochemical composition of the strawberry are reviewed, as is the role played by the maturity, genotype, and storage effects on this fruit. Specific attention is focused on fruit absorption, metabolism, and the possible beneficial biological activity on human health.     

Potential risks and benefits of phytoestrogen-rich diets

Interest in the physiological role of bioactive compounds present in plants has increased dramatically over the last decade. Of particular interest in relation to human health are the class of compounds known as the phytoestrogens, which embody several groups of non-steroidal oestrogens including isoflavones & lignans that are widely distributed within the plant kingdom. Data from animal and in vitro studies provide plausible mechanisms to explain how phytoestrogens may influence hormone dependent states, but although the clinical application of diets rich in these oestrogen mimics is in its infancy, data from preliminary studies suggest potential beneficial effects of importance to health. Phytoestrogens are strikingly similar in chemical structure to the mammalian oestrogen, oestradiol, and bind to oestrogen receptors (ER) with a preference for the more recently described ER beta. This suggests that these compounds may exert tissue specific effects. Numerous other biological effects independent of the ER (e.g. antioxidant capacity, antiproliferative and antiangiogenic effects) have been ascribed to these compounds. Whether phytoestrogens have any biological activity in humans, either hormonal or non hormonal is a contentious issue and there is currently a paucity of data on human exposure. Much of the available data on the absorption and metabolism of dietary phytoestrogens is of a qualitative nature; it is known that dietary phytoestrogens are metabolised by intestinal bacteria, absorbed, conjugated in the liver, circulated in plasma and excreted in urine. Recent studies have addressed quantitatively what happens to isoflavones following ingestion--with pure compound and stable isotope data to compliment recent pharmacokinetic data for soy foods. The limited studies conducted so far in humans clearly confirm that soya isoflavones can exert hormonal effects. These effects may be of benefit in the prevention of many of the common diseases observed in Western populations (such as breast cancer, prostate cancer, menopausal symptoms, osteoporosis) where the diet is typically devoid of these biologically active naturally occurring compounds. However since biological effects are dependent on many factors including dose, duration of use, protein binding affinity, individual metabolism and intrinsic oestrogenic state, further clinical studies are necessary to determine the potential health effects of these compounds in specific population groups. However we currently know little about age related differences in exposure to these compounds and there are few guidelines on optimal dose for specific health outcomes.