大豆异黄酮抗辐射损伤的作用

大豆异黄酮是大豆中的一类多酚化合物。近年来一些体外细胞培养及动物实验表明,大豆异黄酮通过抗氧化、抑制细胞凋亡、调节细胞基因表达等作用机制,对辐射损伤有一定的防护作用。     

大豆异黄酮对电离辐射小鼠脾脏细胞周期、凋亡与增殖的影响

目的：研究大豆异黄酮对辐射小鼠免疫器官脾脏的影响。方法：90只雄性昆明小鼠,随机分为正常组、对照组和补充0．5％大豆异黄酮组,喂养两周后,4．0Gyγ射线照射;于照射后12、24h和一周、两周杀死部分小鼠取脾脏,测定小鼠的脾脏指数、脾脏细胞周期、细胞增殖指数及细胞凋亡率等指标。结果：辐射使小鼠脾脏明显萎缩。脾脏细胞凋亡率和G0-C1期细胞百分比明显增加（P〈0．05）,脾脏细胞S期的百分比及细胞增殖指数明显降低（P〈0．01）;补充大豆异黄酮,可使上述指标更接近正常组水平,使脾脏细胞G0-C1期百分比较辐射对照组明显减少（P〈0．05）,脾脏细胞的C2-M期百分比和细胞增殖指数较辐射对照组明显增加（P〈0．05）。结论：大豆异黄酮可对脾脏起到辐射防护的作用。     

大豆异黄酮抗肿瘤效应研究进展(综述)

大豆异黄酮是大豆生长过程中形成的一类次生代谢产物,对人体具有多种生理功能。研究表明,大豆异黄酮具有抗肿瘤、预防肿瘤作用,是一种很有潜力的癌症化学预防剂,能显著降低多种恶性肿瘤的发病率。现将近几年大豆异黄酮抗肿瘤效应及其机制的研究进展综述如下,以期为大豆异黄酮的深入研究及开发利用提供参考。     

大豆异黄酮神经保护作用研究进展

对大豆异黄酮神经保护作用的研究进展进行综述,旨在为大豆异黄酮功能食品开发以及其他食品功能组分的神经保护作用研究提供科学依据。     

双歧杆菌发酵对豆芽汁中大豆异黄酮含量及组分影响的研究

目的探讨双歧杆菌发酵对豆芽汁中大豆异黄酮含量及组分影响.方法采用HPLC法检测波长260 nm,测定豆芽汁中金省异黄素、大豆黄素的含量.结果表明通过发酵处理后,豆浆中总大豆异黄酮浓度没有明显的变化(P＞0.05);大豆异黄酮甙元的浓度较未经过发酵处理的豆浆组明显增加(P＜0.05);而大豆异黄酮糖甙的浓度却明显降低(P＜0.05).结论豆浆中的大豆异黄酮糖甙在双歧杆菌的β葡萄糖苷酶作用下水解为异黄酮甙元,异常酮甙元的浓度显著增加.     

形态学与形态计量学观察大豆异黄酮对前列腺增生大鼠的作用

目的探讨不同剂量大豆异黄酮(SI)对前列腺增生大鼠组织形态学和超微结构的影响。方法应用丙酸睾酮诱导雄性SD大鼠前列腺增生,随机分为五组:正常对照组、模型组和3个大豆异黄酮剂量组,分别灌胃SI 60、120、240 mg/(kg.d),28 d后,光镜观察前列腺组织形态,同时结合图像分析系统检测前列腺腺体、间质的形态计量学改变,透射电镜观察前列腺细胞超微结构的变化。结果各剂量大豆异黄酮均可降低前列腺增生大鼠前列腺湿重、指数及体积,降低上皮细胞高度、腺体面积、腺体相对总体积、单位体积内腺体平均直径、平均体积、平均表面积和间质相对总体积,提高腺体数目、腺体数密度、腺体表面积/腺体体积和腺体平均曲率。结论大豆异黄酮具有抑制大鼠前列腺增生的作用。     

大豆异黄酮激活PPARγ抑制人乳腺癌MCF-7 细胞增殖

目的:探讨两种大豆异黄酮主要成分染料木黄酮(genistein,GEN)和大豆苷元(daidzein,DAI)抑制人乳腺癌MCF-7细胞增殖的作用与过氧化物酶体增殖激活物受体γ(peroxisome proliferators-activated receptorγ,PPARγ)信号途径的关系。方法:采用免疫细胞化学染色方法观察MCF-7细胞的PPARγ表达情况,PPARγ介导的荧光素酶报告基因检测大豆异黄酮和PPARγ配体罗格列酮(rosiglitazone,ROS)对MCF-7细胞PPARγ的激活作用,MCF-7细胞分别经8×10-5mol/L GEN、DAI和1×10-5mol/L的ROS单独或联合1×10-5mol/L的PPARγ特异性抑制剂GW9662联合处理24、48和72 h后,用CCK-8法检测细胞增殖。结果:MCF-7细胞存在有PPARγ表达,GEN、DAI呈剂量依赖性增强报告基因荧光素酶活性,且这种作用可被GW9662明显阻断;GEN、DAI和ROS呈时间依赖性明显抑制MCF-7细胞增殖(P<0.05),而GW9662可以显著削弱GEN、DAI和ROS对MCF-7细胞的增殖抑制作用(P<0.05)。结论:大豆异黄酮可通过激活乳腺癌MCF-7细胞的PPARγ信号途径抑制其增殖。     

大豆异黄酮激活PPARγ抑制人乳腺癌MCF-7细胞增殖

目的：探讨两种大豆异黄酮主要成分染料木黄酮（genistein,GEN）和大豆苷元（daidzein,DAI）抑制人乳腺癌MCF-7细胞增殖的作用与过氧化物酶体增殖激活物受体γ（peroxisome proliferators-activated receptorγ,PPARγ）信号途径的关系。方法：采用免疫细胞化学染色方法观察MCF-7细胞的PPARγ表达情况,PPARγ介导的荧光素酶报告基因检测大豆异黄酮和PPARγ配体罗格列酮（rosiglitazone,ROS）对MCF-7细胞PPARγ的激活作用,MCF-7细胞分别经8×10-5mol/L GEN、DAI和1×10-5mol/L的ROS单独或联合1×10-5mol/L的PPARγ特异性抑制剂GW9662联合处理24、48和72 h后,用CCK-8法检测细胞增殖。结果：MCF-7细胞存在有PPARγ表达,GEN、DAI呈剂量依赖性增强报告基因荧光素酶活性,且这种作用可被GW9662明显阻断;GEN、DAI和ROS呈时间依赖性明显抑制MCF-7细胞增殖（P〈0.05）,而GW9662可以显著削弱GEN、DAI和ROS对MCF-7细胞的增殖抑制作用（P〈0.05）。结论：大豆异黄酮可通过激活乳腺癌MCF-7细胞的PPARγ信号途径抑制其增殖。     

黑龙江省野生和栽培大豆异黄酮与其组分相关性分析

利用高效液相色谱法（HPLC）检测了黑龙江省556份不同生态区以及不同类型大豆的异黄酮、大豆苷和染料木苷含量,其中野生大豆243份,栽培大豆313份。结果表明：野生大豆异黄酮含量高于栽培大豆,同时筛选出高异黄酮含量种质3份,低异黄酮含量种质2份。异黄酮、大豆苷和染料木苷含量三者问的相关分析表明,大豆异黄酮含量与大豆苷含量及染料木苷含量、大豆苷含量与染料木苷含量均呈极显著正相关。     

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。     

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.     

Modulation of carbohydrate metabolism and peptide hormones by soybean isoflavones and probiotics in obesity and diabetes

Soybean and its isoflavones have been shown to have beneficial effects on carbohydrate and lipid metabolism and on renal function. Probiotics may potentiate the beneficial effects of isoflavones by converting the inactive isoflavone glycoside to aglycones, which are biologically active, thereby producing a synergistic effect. We therefore studied the effects of soybean isoflavones in the presence and absence of probiotics on glucose and triglyceride metabolism and the peptide hormones involved in their metabolism. Lean and obese SHR/N-cp rats were fed AIN-93 diets containing 0.1% soybean isoflavone mixture, 0.1% probiotics mixture or both. Plasma was analyzed for glucose, triglycerides, parameters of renal function and peptide hormones -- insulin, leptin, glucagon and ACTH -- that are involved in glucose and lipid metabolism. Isoflavones given alone lowered plasma glucose in both phenotypes while triglyceride was decreased only in lean animals. Isoflavones also lowered aspartate amino transferase and alanine amino transferase in both phenotypes. Isoflavones had significant effect on plasma insulin, leptin and glucagon in lean rats but not in obese rats. Thus, our data show that in lean animals, isoflavones have hypoglycemic and hypolipidemic effect, and the effect is mediated by changes in peptide hormones. When lipid levels are very high as in obese rats, isoflavones fail to lower plasma triglyceride levels. Probiotics do not appear to enhance the effect of isoflavones.     

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.     

Isoflavones: their effects on cardiovascular risk and functions

PURPOSE OF REVIEW: Isoflavones - plant polyphenols with oestrogenic activity - are becoming widely distributed in foods and sold as nutriceuticals. Their similarity to steroidal oestrogens has stimulated research into potential cardiovascular benefits. The two major areas, those of lipid lowering and of improved vascular function, are reviewed. RECENT FINDINGS: A major plasma cholesterol lowering effect has not been sustained in recent publications. Relatively minor reductions in LDL-cholesterol or non-HDL-cholesterol have generally been reported, but studies in which no reduction was found have also been reported. Fewer publications have dealt with effects on vasculature, but these have been more consistent. Arterial compliance, a parameter of the elasticity or distensibility of large arteries, is improved by as much as has been reported for estrogens. Vasodilatory effects on the microcirculation with isoflavones or their metabolites may provide opportunities for pharmacological intervention. The metabolism of isoflavones is reviewed briefly in order to highlight its complexity. SUMMARY: Although research has failed to demonstrate substantial cholesterol lowering with dietary isoflavones, consumption of legumes is generally to be encouraged as part of the overall strategy for lowering plasma lipids. The favourable effects of ingested or infused isoflavones on several parameters of arterial function suggest an alternative explanation for the apparent low prevalence of coronary disease in populations that eat legumes as a staple food. A better understanding of the pharmacokinetics and bioavailabilty of individual isoflavones is needed if definitive studies are to be designed.     

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。     

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.     

Metabolism of isoflavones in human subjects

Isoflavones form a group of plant compounds that occur mainly in legumes, soy being the most important source in human diet. The high levels of isoflavones in the diet have been associated with a lowered risk for hormone-dependent diseases, including breast and prostate cancers, osteoporosis and cardiovascular disease. The metabolism of isoflavones in humans has been studied to a certain extent, but detailed studies are lacking. This paper reviews the current knowledge on metabolism of isoflavones and presents some preliminary results of a comprehensive soy feeding study, in which the phase I metabolites of soy isoflavones, daidzein, genistein and glycitein, were identified by GC-MS. This revised version was published online in June 2006 with corrections to the Cover Date.