Isoflavone concentrations in the leaves of the species of the genus Trifolium, section Calycomorphum

Abstract

Seventy-six lines of various clovers, representing all extant species of the section Calycomorphum, were assayed at the commencement of flowering stage for their concentrations of the oestrogenic isoflavones formononetin, genistein, and biochanin A. All species tested contained substantial quantities of isoflavone, a characteristic rarely found outside this section. Although most species showed considerable variation in concentrations of the different isoflavones, there does appear to be a characteristic pattern for some of them, and in most of the species there was at least one line with an acceptably low formononetin concentration. T. batmanicum lines generally were high in genistein and low in biochanin A, a characteristic shared with T. subterraneum subsp. brachycalycinurn. This supports other evidence that T. batmanicum is the ancestral species of T. subterraneum, and suggests that T. subterraneum subsp. brachycalycinum may have been the earliest form of subterranean clover.