BIOACTIVE AND OTHER SESQUITERPENES FROM CHILOSCYPHUS-RIVULARIS

Bioassay-directed fractionation of the methyl ethyl ketone extract of Chiloscyphus rivularis yielded five new sesquiterpenes, 12-hydroxychil oscyphone (2), chiloscypha-2,7-dione (3), 12-hydroxychiloscypha-2,7-di one (4), chiloscypha-2,7,9-trione (5), and rivulalactone (6) in additi on to the known sesquiterpenes, 4-hydroxyoppositan-7-one (7), chiloscy phone (1), and isointermedeol (8). The structure and stereochemistry o f rivulalactone, a novel trinorsesquiterpene, was confirmed by its syn thesis starting from 1. Compound 2 showed selective bioactivity in our yeast-based DNA-damaging assay and cytotoxicity to human lung carcino ma cells.