Antimicrobial activity of Hepaticae from Hong Kong and bioactivity-directed isolation of Isoriccardin C1 '-monomethyl ether, a new cyclic bis(bibenzyl) derivative

A total of 34 species of hepatices were collected from various sites of Hon g Kong. Extracts of these species are screened for antimicrobial activity, and 28 species showed repeatable biological activity warranting further inv estigation. From the 95% ethanolic extract of Plagiochila sciophila Nees, g uided by bioactivity-directed isolation, a new cyclic bis(bibenzyl) derivat ive named isoriccardin C1 ' -monomethyl ether (1) and the previously known diterpene dialdehyde perrottetianal A (3) were isolated.