New prenylflavones from the leaves of Epimedium saggitatum.

Five new prenylflavones, yinyanghuo A (1), yinyanghuo B (2), yinyanghuo C (3), yinyanghuo D (4), and yinyanghuo E (5), along with six known flavonoids, chrysoeriol, quercetin, apigenin, apigenin 7,4'-dimethyl ether, kaempferol, and luteolin, were isolated from the leaves of Epimedium sagittatum. Their structures were determined from spectral analysis. Compounds 1 and 2 showed significant antiplatelet induced by arachidonic acid.