Lignans from the liverwort Lepicolea ochroleuca

The polar extract of Lepicolea ochroleuca (Lepicoleaceae) yielded four new lignan conjugates of the most common lignan from liverworts,2,3-dicarboxy-6,7-dihydroxy-1-(3',4'-dihydroxy)-phenyl-1,2-dihydronaphthalene, for which the name epiphyllic acid is introduced. Additional compounds were the two already known 2,4,6-trihydroxyacetophenone-3,5-di-C-glucoside and protocatechuic acid-4-O-beta-glucoside. By means of modern spectroscopic methods, the new lignans were assigned as epiphyllic acid-7-O-beta-glucoside-10-methyl ester, epiphyllic acid-7-O-beta-glucoside-10,51'"-O-shikimic acid ester, epiphyllic acid-7-O-beta-glucoside-9,1""- O-heptitol ester-10,5'"-O-shikimic acid ester, and epiphyllic acid-9,5"'-O-,10,5'"'-O-bis(shikimic acid ester). The chemosystematic of the lignans from liverworts is discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.