Chemical Constituents of the Lichen Cladina macaronesica

Abstract

Column chromatography of the acetone extract of the lichen Cladina macaronesica (Se-phadex LH-20, silica gel and silver nitrate-impregnated silica gel) afforded eight triterpenes identified by chemical and spectral means. a-Amyrenone, lupenone, taraxerol, taraxerone and iso-arborinol acetate were isolated for the first time from lichens and (-)-usnic acid and five mononuclear phenolic compounds were also obtained, four for the first time as natural products. The possible transformation of perlatolic acid into these phenolic compounds is briefly outlined. © 1991, Verlag der Zeitschrift für Naturforschung. All rights reserved.