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|Section2= |Section3= }} Coumestrol is a natural organic compound in the class of phytochemicals known as coumestans. Coumestrol was first identified as a compound with estrogenic properties by E. M. Bickoff in ladino clover and alfalfa in 1957. It has garnered research interest because of its estrogenic activity and prevalence in some foods, including soybeans, brussels sprouts, spinach and a variety of legumes. The highest concentrations of coumestrol are found in clover, Kala Chana, a type of chick pea, and Alfalfa sprouts. Coumestrol is a phytoestrogen, mimicking the biological activity of estrogens. Phytoestrogens are able to pass through cell membranes due to their low molecular weight and stable structure, and they are able to interact with the enzymes and receptors of cells. Coumestrol interacts with the ER-β estrogen receptor and has approximately the same binding affinity for the receptor as 17β-estradiol, but much less affinity than 17α-estradiol, although the estrogenic potency of coumestrol at both receptors is much less than that of 17β-estradiol. The chemical shape of coumestrol orients its two hydroxy groups in the same position as the two hydroxy groups in estradiol, allowing it to inhibit the activity of aromatase and hydroxysteroid dehydrogenase. These enzymes are involved in the biosynthesis of steroid hormones, and inhibition of these enzymes results in the modulation of hormone production. == Natural Sources and Dietary Intake == Levels of coumestrol within individual plants of the same species are variable. Studies of coumestrol levels in alfalfa suggest that there may be a positive correlation between coumestrol production and infection of the plant by viruses, bacteria, and fungi. Higher levels of coumestrol are also found in plants which had been damaged by aphids. Further study is required to fully explain the cause of the correlation between damage, infection, and coumestrol levels. According to the United States Department of Agriculture and Iowa State University database on isoflavanes and coumestrol, coumestrol is found in the following food items. 〔 Based on extrapolation from studies done on animals, the maximum tolerable daily intake of coumestrol for human beings has been estimated at 22 μg per kg of body mass. This was calculated by extrapolating from the lowest level at which adverse effects were seen in animals. Although, due to the variability of the human diet, the exact amount of coumestrol the average person consumes has not been calculated, studies of phytoestrogen intake suggest that most human diets result in a negligible intake of coumestrol relative to the maximum tolerable daily intake. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「coumestrol」の詳細全文を読む スポンサード リンク
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