Two new norcassane-type diterpenoids from Mezonevron sinense Hemsl

Two new norcassane-type diterpenoids, named 6β-hydroxy-bisnorcass-13-en-12-one (1) and 6β-hydroxy-bisnorcassan-12-one (2), were isolated from the seeds of Mezonevron sinense Hemsl. The structures of compounds 1-2 were determined by extensive spectroscopic analysis. Two compounds exhibited immunosuppressive activity with the IC₅₀ values of 19.35 ± 0.87 μM and 18.69 ± 0.88 μM in the ConA induced T cell model and 65.04 ± 0.83 μM and 48.06 ± 0.76 μM in LPS induced B cell model, respectively.