Terpenoids from Chinese Liverworts Scapania spp.

An investigation of the chemical composition of Chinese liverworts led to the isolation of six new caged clerodane-type diterpenoids, scaparins A-C (1-3) from Scapania koponenii and scaparins D-F (4-6) from S. verrucosa. An unknown ent-trachylobane diterpenoid (7) and three known terpenoid derivatives (8-10) were obtained from S. verrucosa. The structures of the compounds were established on the basis of physical data (IR, UV, HRESIMS, and 1D and 2D NMR), and the absolute configurations were unequivocally confirmed by comparison of the experimental and calculated electronic circular dichroism spectra. Preliminary bioassays showed that compounds 1-7 exhibited moderate to weak quinone reductase-inducing activity in Hepa-1c1c7 cells.