Isolation and antimicrobial activity of anthraquinones from some species of the lichen genus Xanthoria

The isolation of six anthraquinones, erythroglaucin, physcion, xanthorin, emodin, fallacinal and teloschistin, from three species of the lichen genus Xanthoria (X. fallax, X. elegáns and A. policarpa) is reported. Physcion is the dominant anthraquinone in all species. The anthraquinones showed broad-spectrum antifungal activity and selective activity against some phytopathogenic bacterial species.