New halimane and clerodane diterpenoids from Croton cnidophyllus.

Three new halimane furanoditerpenoids (1-3) and three new clerodane furanoditerpenoids (4-6), along with seven known terpenoids including four pimarane diterpenoids (7-10) and three norisoprenoids (11-13) were isolated from the 95% EtOH extracts of the plants of Croton cnidophyllus. The 2D structures including absolute configuration of new furanoditerpenoids (1-6) were elucidated by analysis of their HRMS and NMR data as well as comparison of experimental and calculated ECD curves. Bioassay revealed that two compounds (8 and 9) possessed certain inhibitory effects against NO production stimulated by LPS, with IC50 values of 19.00 ± 1.76 and 21.61 ± 1.11 µM, respectively.