Protoilludane-Type and Related Nor-Sesquiterpenes from Phellinus hartigii and Their Anti-Hypertrophic Activities in Rat Cardiomyocytes.

Three nor-sesquiterpenes, phellinharts A-C ( 1 - 3 ), isolated from Phellinus hartigii , exhibited unprecedented protoilludane and cerapicane-type structures. The structures of compounds 1 - 3 were elucidated via spectroscopic analysis, quantum chemical calculations, and X-ray diffraction. Potential biogenic pathways involving demethylation, ring cleavage, and rearrangement were proposed. Compounds 1 - 3 displayed potent anti-hypertrophic activities with low cytotoxicity (CC 50 > 50 μM) in rat cardiomyocytes, underscoring their therapeutic potential.