The chemopreventive properties of soy isoflavonoids in animal models of breast cancer

Genistein (5,7,4-trihydroxyisoflavone), one of two major isoflavonoids in soy, has anti-proliferative effects on mitogen-stimulated cell growth of human breast cancer cells in culture and is a candidate for use in the prevention of breast cancer. Soy protein preparations containing isoflavonoid conjugates have chemopreventive activity in carcinogen-induced rat models of breast cancer. Recent experiments in these models with purified genistein have revealed that the timing of the exposure of rats to this isoflavonoid is critical. Rats treated neonatally or prepuberally with genistein have a longer latency before the appearance of 7,12-dimethylbenz[a]anthracene-induced mammary tumors and a marked reduction in tumor number. The mechanism of genistein's preventive action is in part dependent on its estrogenic activity, which causes a more rapid differentiation of the cells of the mammary gland, analogous to the effects of an early pregnancy. Rats administered genistein after 35 days of age have smaller alterations in breast cancer risk, with a maximum reduction in mammary tumor number of 27%. In ovariectomized nude mice, dietary genistein increases cell proliferation of human breast cancer MCF-7 cell xenografts compared with a control diet. This estrogen-like effect of genistein is not observed in non-ovariectomized rats. Future studies on the anticancer potential of soy isoflavonoids should examine their interaction with other phytochemical components of soybeans and exploit newly developed animal models of breast cancer in which specific genes have been activated or inactivated.     

高效液相色谱法同时测定黄芪中4种异黄酮的含量

目的建立反相高效液相色谱法同时测定黄芪药材中毛蕊异黄酮-7．0-β-D-葡萄糖苷（I）、芒柄花素-7．0-β-D-葡萄糖苷（Ⅱ）、毛蕊异黄酮（Ⅲ）和芒柄花素（Ⅳ）的含量。方法采用C18色谱柱（4．6mm×250mm，5μm）；以乙腈-水为流动相，梯度洗脱；检测波长：254nm。结果4种异黄酮在以下浓度范围内与峰面积呈良好的线性：（I）5．16～660mg·L^-1（r=0．9998）、（Ⅱ）1．18～150mg·L^-1（r=0．9999）、（Ⅲ）2．89～370mg·L^-1（r=0．9999）、（Ⅳ）4．22～540mg·L^-1（r=0．9998）；平均回收率（n=3）分别为：（I）101．4％（RSD=2．97％）、（Ⅱ）95．2％（RSD=2．17％）、（Ⅲ）105．4％（RSD=0．93％）、（Ⅳ）96．9％（RSD=3．13％）。结论该方法简便，准确，灵敏，可用于黄芪药材的质量控制。     

The presence of monoiodinated derivates of daidzein and genistein in human urine and its effect on thyroid gland function

Dietary supplements used by women during menopause are usually based on plant extracts containing isoflavonoids, daidzein and genistein. Genistein is a known inhibitor of many enzymes, including thyroid peroxidase (TPO). In the thyroid follicle, genistein acts as its alternate substrate for the formation of genistein iodinated derivatives. The aim of this study was to search for daidzein- and genistein-iodinated derivatives in urine of isoflavonoid-supplemented women. Additionally, selected phytoestrogens, steroid and thyroid hormones before and after three months of phytoestrogen supplementation were estimated. Urinary levels of free phytoestrogen increased significantly after therapy. They ranged between 0.3–1600, 0.6–670 and 0–206 nmol/L for daidzein, genistein and S-equol, respectively. Monoiodinated derivatives of genistein were observed (0–504 pmol/L) in 60% of the investigated samples. Steroid and thyroid hormone levels were within the normal range and were not significantly altered. The presence of monoiodinated derivates in human urine confirmed that genistein and daidzein may enter human thyroid follicles and influence TPO. Since the levels of the free thyroid hormones were not affected, we propose that the use of phytoestrogen dietary supplements is not associated with the development of thyroid-gland disorders in subjects with adequate iodine intake.     

葛根的化学成分

目的研究葛根(Pueraria lobata)的化学成分。方法采用硅胶柱色谱、Sephadex LH-20柱色谱、反相ODS柱色谱等方法进行分离纯化,根据理化性质及光谱数据确定化合物的结构。结果分离得到13个化合物,分别鉴定为羽扇豆醇(lupeol,1)、芒柄花素(formononetin,2)、水杨酸(salicylicacid,3)、槲皮素(quercetin,4)、染料木素(genistein,5)、α-棕榈酸单甘油酯(2,3-dihydroxypropylpalmitate,6)、葛香豆雌酚(puerarol,7)、大豆素(daidzein,8)、大豆苷(daidzin,9)、葛根素(puerarin,10)、芒柄花苷(ononin,11)、没食子酸(gallic acid,12)、3′-甲氧基葛根素(3′-methoxy puerarin,13)。结论化合物6为首次从该属植物中分离得到,化合物1为首次从该植物中得到。     

Two new isoflavanones from Erythrina costaricensis

Two new isoflavanones, 5,3′-dihydroxy-4′-methoxy-5′-(3-methyl-1,3-butadienyl)-2″,2″-dimethylpyrano[5,6:6,7]isoflavanone (1) and 5,3′-dihydroxy-5′-(3-hydroxy-3-methyl-1-butenyl)-4′-methoxy-2″,2″-dimethylpyrano[5,6:6,7]isoflavanone (2), together with two known isoflavonoids, cristacarpin, and euchrenone b₁₀, were isolated from the stems of Erythrina costaricensis. Their structures were established on the basis of spectroscopic evidence. These new compounds are rare isoflavanones, possessing both a 2,2-dimethylpyran substituent and a prenyl analog. The antibacterial activities of 1 and 2 against the methicillin-resistant Staphylococcus aureus were examined.     

越南槐种子化学成分的分离与鉴定

目的:研究豆科苦参属越南槐Sophoratonkinensis种子的化学成分.方法:采用MCI树脂、正相硅胶色谱、凝胶柱色谱、半制备高效液相色谱法等方法进行分离纯化,通过理化性质、波谱数据结合参考文献鉴定化合物结构,并采用琼脂稀释法测定部分化合物的体外抗幽门螺杆菌活性.结果:从越南槐种子的甲醇提取物中共分离得到了 22...     

维药野苜蓿中异黄酮类成分的提取工艺研究

目的:以新疆野苜蓿为原料,对野苜蓿中异黄酮含量进行了分析研究。方法:采用不同提取方法从野苜蓿中提取异黄酮。结果:野苜蓿异黄酮的最佳提取工艺为乙醇浓度为70%,料液比为1∶8(g/mL),提取温度为70℃,提取时间为2 h,在最佳参数组合下苜蓿叶中异黄酮的最大提取率为0.90%。结论:该研究为进一步开发苜蓿属植物资源提供了一定的理论依据。     

Novel Insights into the Pharmacology of Flavonoids

Flavonoids are widely distributed secondary metabolites and currently consumed in large amounts in the daily diet. In this article, some of the most recent developments in flavonoid – and related polyphenolic compounds – pharmacology are discussed, with particular emphasis on very recent data, most of which are published in Phytotherapy Research, which highlight new aspects in flavonoid anti‐inflammatory, antilipidemic, antihyperglycemic, antiviral, hepatoprotective, gastric antiulcer, cardioprotective, neuroprotective, antioxidant and anticancer actions. These updated data confirm the well‐established diverse beneficial pharmacological actions and might support the perspective for a therapeutic use. Copyright © 2013 John Wiley & Sons, Ltd.     

In Vitro Study of Isoflavones and Isoflavans as Potent Inhibitors of Human 12‐ and 15‐Lipoxygenases

In this study, we have investigated 16 isoflavone and isoflavan derivatives as potential inhibitors of human lipoxygenase (platelet 12‐lipoxygenase, reticulocyte 15‐lipoxygenase‐1, and epithelial 15‐lipoxygenase‐2). The flavonoid baicalein, a known lipoxygenase inhibitor, was used as positive control. Four compounds, 6,7‐dihydroxy‐3′‐chloroisoflavone ( 1c ), 7‐hydroxy‐8‐methyl‐4′‐chloroisoflavan ( 5a ), 7,8‐dihydroxy‐4′‐methylisoflavan ( 5b ), and 7,8‐dihydroxy‐3′‐methylisoflavan ( 5c ), were effective inhibitors of 12‐lipoxygenases and 15‐lipoxygenase‐1 with IC₅₀'s <10 μm , while 6,7‐dihydroxy‐4′‐nitroisoflavone ( 1b ) was a selective inhibitor of 12‐lipoxygenases. Docking studies, antioxidant assays, and kinetic measurements were carried out for the three best inhibitors ( 1b , 5b , 5c ). The results showed that a catechol group in ring A is critical for the antioxidant properties of these compounds, and probably essential for their inhibitory activity. Kinetic assays showed that compounds 1b , 5b , and 5c are competitive inhibitors with K_i values in the range of 0.3–3 μm .     

Purification and structure determination of gelatinase and collagenase inhibitors from Viola patrinii fermentation extracts

Investigation of collagenase and gelatinase inhibitory natural components afforded two isoflavonoids. Two isoflavonoids, tectorigenin-7-O-β-D-glucoside (1) and luteolin-7-O-β-D-glucuronopyranoside (2), were isolated from ethyl acetate fraction of Viola patrinii fermentation extracts (VPFE). Of these, compounds 1 and 2 exhibited collagenase inhibitory activity (IC₅₀) at a concentration of less than 1.5?μM, and compound 2 showed gelatinases A and B inhibitory activity (IC₅₀) at 0.3?μM and 0.8?μM, respectively.