Hapmnioides A–C, Rearranged Labdane-Type Diterpenoids from the Chinese Liverwort Haplomitrium mnioides

Many exceptional labdane-type diterpenoids have been exclusively found in liverworts, which serve as taxonomic molecules or play important ecological roles in interactions among organisms. Three unprecedented labdane-type diterpenoids hapmnioides A (1), B (2), and C (3) formed through cascade rearrangement from the Chinese liverwort Haplomitrium mnioides are reported. Their structures were established by comprehensive spectroscopic analysis coupled with single-crystal X-ray diffraction, and their anti-inflammatory activities were also preliminarily tested.