(-)-Dihydromylione A, a novel tetracyclic sesquiterpene ketone containing two conjugated cyclopropane rings, from Mylia taylorii (liverwort).

A novel tetracyclic sesquiterpene ketone named (-)-dihydromylione A (III) was isolated from the liverwort, and the structure was determined together with the absolute configuration to be ent-5, 10-cyclo-aromadendr-3-one by connecting the compound with co-occurring (-)-myliol (II).