Distribution of isoflavones and coumestrol in neglected tropical and subtropical legumes

BACKGROUND: Isoflavones and coumestrol from dietary legumes are plant constituents showing multiple beneficial effects on humans. Owing to their ability to bind with mammalian estrogenic receptors and thereby intervention in several kinds of hormone‐related cancers, they have received much attention. Soybean (Glycine max) is currently the major source of isoflavonoids in human diet. However, dozens of tropical and subtropical leguminous species remain unexplored for their isoflavonoids content. RESULTS: We have analyzed 55 extracts from 41 tropical and subtropical legume species used either in human or animal diet by high‐performance liquid chromatography for the content of soy isoflavones, biochanin A, daidzein, daidzin, formononetin, genistein, genistin, sissotrin, ononin and the coumestan coumestrol. Genistein and biochanin A were the most abundant compounds. The highest content of genistein was found in aerial parts of Andira macrothyrsa, seeds of Pachyrhizus tuberosus and aerial parts of Calopogonium mucunoides (598, 250 and 184 µg g^?1, respectively) and biochanin A in aerial parts of Cratylia argentea, C. mucunoides and flowers of A. macrothyrsa (76, 53 and 40 µg g^?1, respectively). CONCLUSION: None of the samples tested was richer overall source of soy isoflavones and coumestrol than soybean; nevertheless several species (C. mucunoides or A. macrothyrsa) may serve as a promising source of individual compounds. © 2012 Society of Chemical Industry     

Risks and benefits related to alimentary exposure to xenoestrogens

Xenoestrogens are widely diffused in the environment and in food, thus a large portion of human population worldwide is exposed to them. Among alimentary xenoestrogens, phytoestrogens (PhyEs) are increasingly being consumed because of their potential health benefits, although there are also important risks associated to their ingestion. Furthermore, other xenoestrogens that may be present in food are represented by other chemicals possessing estrogenic activities, that are commonly defined as endocrine disrupting chemicals (EDCs). EDCs pose a serious health concern since they may cause a wide range of health problems, starting from pre-birth till adult lifelong exposure. We herein provide an overview of the main classes of xenoestrogens, which are classified on the basis of their origin, their structures and their occurrence in the food chain. Furthermore, their either beneficial or toxic effects on human health are discussed in this review.     

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.     

G蛋白偶联雌激素受体研究进展及在食品功能评价中的应用

大量研究结果证明,尽管植物化学物、中草药和植物雌激素类化合物都具有丰富性、多样性,但是在结构和功能上却显示出很多共性——几乎都具有雌激素类功能.研究还发现,大多数植物雌激素类化合物均能与雌激素受体(estrogen receptors,ERs),特别是ERα和ERβ相识别,进一步与核受体超家族形成互作网络,调节细胞核中...     

The Potent Phytoestrogen 8-Prenylnaringenin: A Friend or a Foe?

8-prenylnaringenin (8-PN) is a prenylated flavonoid, occurring, in particular, in hop, but also in other plants. It has proven to be one of the most potent phytoestrogens in vitro known to date, and in the past 20 years, research has unveiled new effects triggered by it in biological systems. These findings have aroused the hopes, expectations, and enthusiasm of a “wonder-drug” for a host of human diseases. However, the majority of 8-PN effects require such high concentrations that they cannot be reached by normal dietary exposure, only pharmacologically; thus, adverse impacts may also emerge. Here, we provide a comprehensive and up-to-date review on this fascinating compound, with special reference to the range of beneficial and untoward health consequences that may ensue from exposure to it.     

Anti-Atherosclerotic Effects of a Phytoestrogen-Rich Herbal Preparation in Postmenopausal Women

The risk of cardiovascular disease and atherosclerosis progression is significantly increased after menopause, probably due to the decrease of estrogen levels. The use of hormone replacement therapy (HRT) for prevention of cardiovascular disease in older postmenopausal failed to meet expectations. Phytoestrogens may induce some improvements in climacteric symptoms, but their effect on the progression of atherosclerosis remains unclear. The reduction of cholesterol accumulation at the cellular level should lead to inhibition of the atherosclerotic process in the arterial wall. The inhibition of intracellular lipid deposition with isoflavonoids was suggested as the effective way for the prevention of plaque formation in the arterial wall. The aim of this double-blind, placebo-controlled clinical study was to investigate the effect of an isoflavonoid-rich herbal preparation on atherosclerosis progression in postmenopausal women free of overt cardiovascular disease. One hundred fifty-seven healthy postmenopausal women (age 65 ± 6) were randomized to a 500 mg isoflavonoid-rich herbal preparation containing tannins from grape seeds, green tea leaves, hop cone powder, and garlic powder, or placebo. Conventional cardiovascular risk factors and intima-media thickness of common carotid arteries (cIMT) were evaluated at the baseline and after 12 months of treatment. After 12-months follow-up, total cholesterol decreased by 6.3% in isoflavonoid-rich herbal preparation recipients (p = 0.011) and by 5.2% in placebo recipients (p = 0.020); low density lipoprotein (LDL) cholesterol decreased by 7.6% in isoflavonoid-rich herbal preparation recipients (p = 0.040) and by 5.2% in placebo recipients (non-significant, NS); high density lipoprotein (HDL) cholesterol decreased by 3.4% in isoflavonoid-rich herbal preparation recipients (NS) and by 4.5% in placebo recipients (p = 0.038); triglycerides decreased by 6.0% in isoflavonoid-rich herbal preparation recipients (NS) and by 7.1% in placebo recipients (NS). The differences between lipid changes in the isoflavonoid-rich herbal preparation and placebo recipients did not reach statistical significance (p > 0.05). Nevertheless, the mean cIMT progression was significantly lower in isoflavonoid-rich herbal preparation recipients as compared to the placebo group (6 μm, or <1%, versus 100 μm, or 13%; p < 0.001 for the difference). The growth of existing atherosclerotic plaques in isoflavonoid-rich herbal preparation recipients was inhibited by 1.5-fold (27% versus 41% in the placebo group). The obtained results demonstrate that the use of isoflavonoid-rich herbal preparation in postmenopausal women may suppress the formation of new atherosclerotic lesions and reduce the progression of existing ones, thus promising new drug for anti-atherosclerotic therapy. Nevertheless, further studies are required to confirm these findings.     

Implications of antinutritional components in soybean foods

There are a number of components present in soybeans that exert a negative impact on the nutritional quality of the protein. Among those factors that are destroyed by heat treatment are the protease inhibitors and lectins. Protease inhibitors exert their antinutritional effect by causing pancreatic hypertrophy/hyperplasia, which ultimately results in an inhibition of growth. The lectin, by virtue of its ability to bind to glycoprotein receptors on the epithelial cells lining the intestinal mucosa, inhibits growth by interfering with the absorption of nutrients. Of lesser significance are the antinutritional effects produced by relatively heat stable factors, such as goitrogens, tannins, phytoestrogens, flatus‐producing oligosaccharides, phytate, and saponins. Other diverse but ill‐defined factors appear to increase the requirements for vitamins A, B₁₂, D, and E. The processing of soybeans under severe alkaline conditions leads to the formation of lysinoalanine, which has been shown to damage the kidneys of rats. This is not generally true, however, for edible soy protein that has been produced under milder alkaline conditions. Also meriting consideration is the allergenic response that may sometimes occur in humans, as well as calves and piglets, on dietary exposure to soybeans.     

Genistein affects ovarian folliculogenesis: A stereological study

The effects of short‐term genistein exposure on ovarian folliculogenesis in immature rats were examined stereologically. To determine whether genistein acts as an estrogen agonist or antagonist, the results were compared with the effects of 17α‐ethynylestradiol. Immature female rats received 50 mg/kg/bw of genistein in dimethyl sulfoxide subcutaneously daily for three consecutive days from 18 to 20 days. The second group was injected with 1 μg/kg/bw of 17α‐ethynylestradiol in olive oil in the same schedule. Each group had a corresponding control. Genistein increased ovary and ovarian stroma volumes by 18.50% (P < 0.05) and 53.40% (P < 0.05), respectively, and changed the parenchyma to stroma ratio in favor of stroma. Genistein induced decreases in the number of primordial (by 17.23%; P < 0.05), primary (16.62%; P < 0.05), and secondary follicles (12.29%: P < 0.05), whereas the number of atretic secondary follicles increased (5.10‐fold; P < 0.05). The number of healthy large follicles was raised by 27.3% (P < 0.05), accompanied by 35.64% more atretic large follicles (P < 0.05). Similarly to genistein, estradiol changed the parenchyma to stroma ratio in favor of stroma, and reduced the number of primordial follicles, but the number of primary follicles was elevated. There were more healthy and atretic small and large follicles. In conclusion, genistein acted as an estrogen antagonist and had an inhibitory effect on the initial phase of folliculogenesis. In the other phases, genistein acted as an estrogen agonist, stimulating transition from the preantral to antral stage of folliculogenesis, and altering the ratio of follicular parenchyma and ovarian stroma in favor of stroma. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

大豆异黄酮代谢产物及其分析方法研究

异黄酮是豆类等植物中含有一类具有生物活性植物性雌激素,它对人类某些疾病防治具 有一定作用,国内外采用许多分离技术对异黄酮及其代谢产物进行研究。该文介绍大豆异黄酮结 构及代谢,并阐述目前分析异黄酮及其代谢产物最新方法。