大豆异黄酮的微生物转化

大豆异黄酮是近年来发现的具有多种生物学活性的大豆营养成分。综述了微生物对大豆异黄酮的转化过程,对大豆异黄酮的生物利用和营养成分的影响,指出在富含大豆异黄酮类制品生产过程中合理利用微生物活动的重要意义和可能途径。     

大豆异黄酮生物合成关键酶及其代谢工程研究进展

异黄酮是一类具有C-6/C-3/C-6骨架的二次代谢产物,具有抗氧化和抗肿瘤活性。异黄酮与黄酮类物质具有相似的苯丙烷生物合成途径。天然的绝大部分异黄酮分布在豆科植物中,目前在大豆中已经发现了超过12个异黄酮(苷)。大豆异黄酮的生物合成主要涉及三个关键的酶查尔酮合酶(CHS)、查尔酮异构酶(CHI)和异黄酮合酶(IFS)。总结了大豆异黄酮的提取分离方法和生物合成途径,着重综述了CHI、CHS、IFS生物学特征和功能及异黄酮的代谢工程研究。     

大豆异黄酮微生物转化研究进展

大豆异黄酮是大豆在其生长过程中形成的一类次生代谢产物,具有抗氧化、抗癌、减少骨质流失、降低心脑血管发病率等多种生理功能。目前已知,被摄人机体的大豆异黄酮将被肠道微生物菌群转化为具有更高、更广生物学活性的不同产物。因此,大豆异黄酮对人体的有益调节作用强弱并不简单取决于摄人机体的净含量的多少,更在于被摄人机体的大豆异黄酮将如何被肠道菌群转化。本文从大豆异黄酮的组成与功能、大豆异黄酮体内吸收、代谢及微生物转化、转化产物的活性以及高效合成等方面进行了系统综述,对大豆异黄酮微生物生物转化研究现状和存在问题进行分析总结,并对今后发展趋势进行展望,旨在推动高活性大豆异黄酮微生物转化产物的研究与开发。     

崖豆藤属植物中异黄酮类化学成分及其药理活性的研究进展

本文对豆科崖豆藤属植物中的异黄酮类化学成分及此类成分药理活性的国内外研究进行综述。从崖豆藤属植物中分离得到异黄酮类化合物159个,包括异黄酮及其苷类、鱼藤酮类、异黄烷类、紫檀烷类、二氢异黄酮类,它们具有抗肿瘤、抗炎、抗雌激素等作用。     

肠道微生物代谢产物—S-雌马酚与 人类健康关系研究进展

大豆异黄酮是一种年销量很大、市场普及率较高的保健品。具有抗氧化、抗肿瘤等功能,对延缓女性衰老和改善更年期综合征有很好效果。但研究表明,大豆异黄酮的保健功能主要归功于其肠道代谢产物S-雌马酚。S-雌马酚是豆类食品在肠道内经特定微生物代谢后产生的一种高度稳定小分子,其与雌激素的结构和功能高度相似,能与β-雌激素(ER-β)受体结合。具有防治更年期综合征、心血管疾病和多种雌素依赖性癌症的功能。到目前为止,雌马酚的功能及其与人类健康之间的关系还有待进一步研究。本文结合国内外最新研究进展,着重介绍雌马酚的生理功能及其与各类疾病的研究进展,展望雌马酚在各类疾病防治中可能发挥的重要作用。     

传统大豆发酵食品中大豆异黄酮的生理保健机能的研究进展

大豆异黄酮属于黄酮类化合物,是一类具有重要生物活性的化合物,在大豆和传统大豆发酵食品中含量丰富。近年来研究发现大豆异黄酮在预防癌症、骨质疏松症、心血管疾病和改善妇女更年期综合症等方面具有广泛的生理活性,因此引起了国内外学者的广泛关注。大豆异黄酮的研究,不仅为功能性大豆制品的开发提供理论基础,也为人们合理的膳食提供参考。综述近年来国内外对大豆异黄酮生理保健机能的研究进展。     

大豆异黄酮对游泳大鼠能量代谢和抗氧化功能的影响

大豆异黄酮具有多种生物活性,本研究旨在揭示其对游泳大鼠能量代谢和抗氧化功能的影响。将30只雄性SD大鼠随机分为正常组、游泳组和大豆异黄酮组,每组10只。大豆异黄酮组大鼠按照5 g/kg的剂量喂养大豆异黄酮饲料2周,正常组和游泳组大鼠按标准饲料喂养2周。游泳组和大豆异黄酮组大鼠按体重的5%进行45 min的负重游泳。分别检测各组大鼠游泳后的血清乳酸(Lac)、尿素氮(BUN)、游离脂肪酸(NEFA)、三磷酸腺苷(ATP)、肌酸激酶(CK)、丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)及总抗氧化能力。研究显示,大豆异黄酮可抑制负重游泳诱导的Lac和BUN水平升高,并且提高大鼠血清、肝脏及骨骼肌中的NEFA水平。大豆异黄酮可提高大鼠骨骼肌的ATP和CK水平。大豆异黄酮可抑制负重游泳诱导的MDA水平的升高,并抑制SOD和GSH-Px水平的降低。初步结论表明,大豆异黄酮可通过增加游泳大鼠的脂肪动员并减少蛋白质分解来调节能量代谢,提高大鼠的耐力和抗疲劳能力。此外,大豆异黄酮可通过抑制运动过程中的脂质过氧化反应来减少氧化应激,并且通过增强机体清除自由基的能力来提高抗氧化功能。     

大豆对预防老年痴呆的研究进展

随着人口老龄化问题的加剧,老年痴呆的发病比例逐年上升,并已成为困扰全人类的重大疾病问题。在缺乏明确治疗手段的情况下通过饮食结构调整进行提早预防对于改善现状具有重要意义。大豆是人类饮食中重要的组成部分,因其富含大豆异黄酮、大豆磷脂、γ-氨基丁酸(GABA)等多种对老年痴呆具有改善作用的生物活性物质而备受关注。综述了大豆磷脂、大豆异黄酮及GABA对预防老年痴呆的研究进展,并概述了萌芽在改善大豆营养组分方面的应用,以期为老年痴呆的防治及拓宽大豆在老年痴呆防治上的应用提供理论依据。     

大蒜中有机硫化物抗肿瘤的研究进展

大蒜是一种古老的药用植物,具有广谱的抗肿瘤作用,发挥其主要抗肿瘤作用的是多种烯丙基有机硫化物。从大蒜中有机硫化物调节致癌物的代谢、抑制肿瘤细胞周期、诱导肿瘤细胞凋亡、消除自由基和抗氧化等方面,对其抗肿瘤作用机制研究进展作一综述。     

糖类及其衍生物的抗肿瘤作用

糖类不仅本身具有抗肿瘤等多种生物活性,同时发现其经过修饰后的衍生物也具有独特的作用.糖类及其衍生物抗肿瘤活性的研究已成为生物化学和医学领域的前沿,对寻找新型糖类抗肿瘤药物有重要的意义.     

Molecular mechanisms of action of the soy isoflavones includes activation of promiscuous nuclear receptors. A review

Consumption of soy has been demonstrated to reduce circulating cholesterol levels, most notably reducing low-density lipoprotein (LDL) cholesterol levels in hypercholesterolemic individuals. The component or components that might be responsible for this effect is still a matter of debate or controversy among many researchers. Candidate agents include an activity of soy protein itself, bioactive peptides produced during the digestive process, or the soy isoflavones. Although soy intake may provide other health benefits including preventative or remediative effects on cancer, osteoporosis and symptoms of menopause, this review will focus on isoflavones as agents affecting lipid metabolism. Isoflavones were first discovered as a bioactive agent disrupting estrogen action in female sheep, thereby earning the often-used term 'phytoestrogens'. Subsequent work confirmed the ability of isoflavones to bind to estrogen receptors. Along with the cholesterol-lowering effect of soy intake, research that is more recent has pointed to a beneficial antidiabetic effect of soy intake, perhaps mediated by soy isoflavones. The two common categories of antidiabetic drugs acting on nuclear receptors known as peroxisome proliferator activated receptors (PPARs) are the fibrates and glitazones. We and others have recently asked the research question 'do the soy isoflavones have activities as either "phytofibrates" or "phytoglitazones"?' Such an activity should be able to be confirmed both in vivo and in vitro. In both the in vivo and in vitro cases, this action has indeed been confirmed. Further work suggests a possible action of isoflavones similar to the nonestrogenic ligands that bind the estrogen-related receptors (ERRs). Recently, these receptors have been demonstrated to contribute to lipolytic processes. Finally, evaluation of receptor activation studies suggests that thyroid receptor activation may provide additional clues explaining the metabolic action of isoflavones. The recent advances in the discovery and evaluation of the promiscuous nuclear receptors that bind many different chemical ligands should prove to help explain some of the biological effects of soy isoflavones and other phytochemicals.     

Biofluid 1H NMR-based metabonomic techniques in nutrition research - metabolic effects of dietary isoflavones in humans

A metabonomic approach to nutrition research may provide an insight into in vivo mechanisms of action following nutritional intervention. This approach was applied to investigate changes in the (1)H NMR spectral profile of urine collected from controlled dietary intervention studies conducted in premenopausal women before and following soy or miso consumption. The aim of the study was to identify the biochemical effects of a diet rich in soy isoflavones, phytochemicals which are receiving significant attention because of their potential importance to human health and wide bioactivity in vitro. By applying various chemometric techniques to the data the biochemical effects of conjugated and unconjugated isoflavones were determined. The biochemical changes observed suggest that soy isoflavone ingestion had significant effects on several metabolic pathways associated with osmolyte fluctuation and energy metabolism. These biochemical changes were more significant following ingestion of the unconjugated soy isoflavone (miso) diet suggesting that the chemical composition of the isoflavones present in soy-based foods may have an effect on their biological efficacy in vivo. This study describes a novel application for (1)H NMR analysis by determining subtle differences in biochemical profiles following dietary intervention and providing further insight into the mechanisms of action of phytochemicals in vivo.     

Soy isoflavones and cognitive function

There is growing interest in the physiological functions of soy isoflavones, especially in whether they affect cognitive function and have beneficial effects on neurodegenerative diseases. Here we review the recent evidence from clinical and experimental studies supporting a role for soy isoflavones in cognitive function. Soy isoflavones may mimic the actions and functions of estrogens on brain, and they have been shown to have positive effects on the cognitive function in females; however, studies on their effects on spatial memory have not provided consistent results in males. Although data from humans, cultures, and animal models are currently insufficient for elucidating the metabolism of soy isoflavone actions on cognitive function and the nervous system, we suggest two putative pathways; (1) an estrogen receptor-mediated pathway and (2) via the inhibition of tyrosine kinase, in particular by genistein, which is one of the soy isoflavones. Although soy isoflavones appear to have a positive effect on brain function, further research is needed to determine not only the efficacy but also the safety of soy isoflavones on the nervous system and cognitive function.     

Regulation of soy isoflavones on weight gain and fat percentage: evaluation in a Chinese Guangxi minipig model

This study was conducted to determine the effects of soy isoflavones on changes in body and tissue weight and on insulin-like factor I (IGF-I) and peroxisome proliferator-activated receptor-γ (PPARγ) gene and protein expression in muscle and adipose tissues in Chinese Guangxi minipig, as a model for studying human nutrition. A total of 72 male Chinese Guangxi minipigs were fed basal diet (control, Con), low dose of soy isoflavones and high dose of soy isoflavones (HSI). The results showed that HSI increased the body weight (BW) gain and fat percentage of minipigs (P < 0.05). In addition, the serum concentrations of IGF-I and interleukin-6 were increased by high levels of soy isoflavones (P < 0.05). Furthermore, a diet containing soy isoflavones enhanced IGF-I mRNA expression levels in longissimus muscle, but decreased these levels in perirenal fat. However, the mRNA and protein expression levels of PPARγ in longissimus muscle and subcutaneous adipose tissue were both increased when compared with the Con. The data indicated that soy isoflavones regulated the BW gain and fat percentage of Chinese Guangxi minipigs, which also showed changes in IGF-I system and PPARγ. However, further research is required to clarify the causative relationship.     

The effects of soy isoflavones on obesity

Over the last decades, the prevalence of obesity and related diseases has increased rapidly in the Western world. Obesity is a disorder of energy balance and is associated with hyper-insulinemia, insulin resistance, and abnormalities in lipid metabolism, and it is one of the most important risk factors in the development of Type II diabetes, cardiovascular disease, atherosclerosis, and certain cancers. Because of the lower frequency of these diseases in Asian countries, attention has been turned toward the Asian diet, which consists highly of soy and soy-based products. The health benefits associated with soy consumption have been linked to the content of isoflavones, the main class of the phytoestrogens. As a result of their structural similarities to endogenous estrogens, isoflavones elicit weak estrogenic effects by competing with 17beta-estradiol (E2) for binding to the intranuclear estrogen receptors (ERs) and exert estrogenic or antiestrogenic effects in various tissues. The estrogenic activities of soy isoflavones are thought to play an important role in their health-enhancing properties. Additionally, the isoflavones have been proved to exert non-ER-mediated effects through numerous other pathways. Genistein, daidzein, and glycitein are the principal isoflavones in soy. Genistein is the most thoroughly examined of these, because it is the most prevalent isoflavone in soy and the most active of these compounds, because of its higher binding affinity for the ER. Genistein and daidzein can be obtained in high levels in humans under certain nutritional conditions, and epidemiologic and laboratory data suggest that these compounds could have health benefits in human obesity. This review will focus on the latest results of research on isoflavones and their effect on obesity in cell cultures, rodents, and humans.     

Effects of chronic exposure to soy meal containing diet or soy derived isoflavones supplement on semen production and reproductive system of male rabbits

Soy and derivative diets deliver large doses of isoflavones to human and animals throughout their lifespan, including gestation. Epidemiologic and experimental data suggest that the consumption of soybean containing foods may protect against cardiovascular disease and decrease breast, prostate and endometrial cancer risk. Based on animal and in vitro studies, however, concerns have been raised that consumption of isoflavones may cause potential adverse effects on the reproductive tract and behavior. The aim of this study was to investigate the effects of chronic consumption of a soy meal containing diet or soy isoflavones supplement on the morphology of reproductive organs, semen quality, age that males reached puberty, and sexual behavior of male rabbits. With this purpose, 16 female rabbits were randomly assigned to receive: (1) a soy- and alfalfa-free diet; (2) a soy- and alfalfa-free diet supplemented with 5mg/kg body wt./day of soy isoflavones; (3) a soy- and alfalfa-free diet supplemented with 20mg/kg body wt./day of soy isoflavones; (4) a diet containing 18% of soy meal, throughout the gestation and lactation. After weaning, male offspring received the same diet, which was given to the respective mother. The age that males reached puberty, semen characteristics and sexual behavior were evaluated in these animals. At 33 weeks of age, the reproductive organs were submitted to histological evaluation. Rabbits, which received large amounts of isoflavones (20mg/kg body wt./day) had a lesser food intake, body weight and semen volume. Spermatogenesis, morphology of male genital organs and sexual behavior did not differ significantly from the control group. We conclude that chronic dietary treatment with soy based diet or soy isoflavones have no adverse effects on the observed reproductive patterns of male rabbits.     

雷公藤红素抗肿瘤作用及机制研究进展

雷公藤红素是我国传统中药雷公藤中的天然活性成分,具有抗类风湿、抗炎、抗肿瘤等多种生物学活性。近年来,雷公藤红素由于低毒、多靶点、广谱性等优势,在抗肿瘤治疗中备受关注。雷公藤红素可以通过调控PI3K/AKT、NF-κB、MAPK和STAT3等多种信号通路抑制肿瘤增殖、侵袭和转移,诱导肿瘤细胞凋亡。综述了雷公藤红素的抗肿瘤作用及机制,以期促进雷公藤红素的深入研究与应用。     

Increased aggressive behavior and decreased affiliative behavior in adult male monkeys after long-term consumption of diets rich in soy protein and isoflavones

Estrogen produced by aromatization of gonadal androgen has an important facilitative role in male-typical aggressive behavior that is mediated through its interaction with estrogen receptors (ER) in the brain. Isoflavones found in soybeans and soy-based dietary supplements bind ER and have dose- and tissue-dependent effects on estrogen-mediated responses. Yet, effects of isoflavone-rich diets on social and aggressive behavior have not been studied. We studied the effects of long-term (15 months) consumption of diets rich in soy isoflavones on spontaneous social behavior among adult male cynomolgus macaques (Macaca fascicularis) (n = 44) living in nine stable social groups. There were three experimental conditions which differed only by the source of dietary protein: casein and lactalbumin (no isoflavones), soy protein isolate containing 0.94 mg isoflavones/g protein, and soy protein isolate containing 1.88 mg isoflavones/g protein. In the monkeys fed the higher amount of isoflavones, frequencies of intense aggressive (67% higher) and submissive (203% higher) behavior were elevated relative to monkeys fed the control diet (P's < 0.05). In addition, the proportion of time spent by these monkeys in physical contact with other monkeys was reduced by 68%, time spent in proximity to other monkeys was reduced 50%, and time spent alone was increased 30% (P's < 0.02). There were no effects of treatment on serum testosterone or estradiol concentrations or the response of plasma testosterone to exogenous gonadotropin-releasing hormone (GnRH). The results indicate that long-term consumption of a diet rich in soy isoflavones can have marked influences on patterns of aggressive and social behavior.