The occurrence of isoflavones in some domestic clover varieties

Preliminary investigations were carried out in order to ascertain the occurrence of isoflavonoid compounds characterized by estrogenic activity, in five domestic species of clover: <i>Trifolium pratense</i> L., <i>T. repens</i> L., <i>T. incarnatum</i> L., <i>T. resupinatum</i> L. and <i>T. hybridum</i> L. Large amounts of biochanin A (0.8% d.m.) and formononetin (0.7% d.m.) and small amounts of genistein were identified in the green parts of red clover. In the remaining species, small amounts of formononetin and genistein were found. In all the species of clover, free isoflavonoid aglycones and glycosides were found. Laboratory tests carried out on mice showed that only <i>T. pratense</i> contained high estrogen activity. Red clover also had an unidentified factor which inhibited the increase of the body weight of young mice.