Chemical constituents from Chinese liverworts and their biological significances

The dimorphic yeast Candida albicans is the most prevalent human fungal pathogen due to its high frequency of clinical isolation and the much amount of morbidity and mortality it causes. The natural high tolerance for antifungal drugs and the increase of clinically resistant C. albicans strains have lent the urgency for the development of new antifungal drugs. Such compounds should inhibit the morphological transition from yeast to filament which is one property contributing to C. albicans virulence. As a part of our ongoing research program on the isolation and identification of potentially antifungal compounds from the Chinese liverworts, over 30 macrocyclic bisbibenzyls have been isolated in our lab, including new bibenzofurane bisbibenzyls, which paves the way for screening the small molecule that block morphogenesis in C. albicans and obtaining structure-activity relationship data. Riccardin D, one of the macrocyclic bibibenzlyls was found to inhibit C. albicans biofilm formation with a sub-MIC concentration, which is associated with its block of hyphal growth. The underlined mechanism was also investigated. Riccardin D -Riccardin D +Riccardin D