Flavonoids and the taxonomy of Cercis

Flavonoids of ii samples of Cercis, comprising seven species, were isolated and identified. Only 3-O-monoglycosides of kaempferol, quercetin and myric etin were obtained. Bauhinia (the largest genus in tribe Cercideae) is akin to Cercis because flavones are rarely found in the former. On the other ha nd, species of Bauhinia often present glycosides of isorhamnetin and a wide r diversity of glycosides, and only rarely present myricetin. The frequent occurrence of this flavonol and the simpler flavonoid profile of Cercis may reflect a greater antiquity of Cercis as compared with Bauhinia. With the exception of C. canadensis var, mexicana, Cercis taxa from xerophytic habit ats did not yield kaempferol glycosides in detectable amounts, as opposed t o taxa from mesophytic habitats. The results obtained are consistent with p roposals of merging C. reniformis into synonymy of C, occidentalis, as well as the recognition of two North American species, C. canadensis and C. occ identalis, and the recognition of the Asian C. gigantea. (C) 2000 Elsevier Science Ltd. All Rights reserved.