Bioactive cembrane diterpenoids from the gum resin of Boswellia carterii.

Abstract Eight new cembrane-type diterpenoids, boscartins AP-AW (1–8) were obtained from the gum resin of Boswellia carterii. Among which, six ones (2–7) were isomers, with one hydroxy group and two double bonds migrating along the carbocycle. The structures were elucidated by spectroscopic examination. All isolates were evaluated for anti-inflammatory activity and hepatoprotective activity by cell models of LPS-induced RAW 264.7 mouse peritoneal macrophages and APAP-induced HepG2 cells, respectively. As for anti-inflammatory activity assay, compound 1 exhibited potent activity against NO production (IC50 of 13.1 μM), with the other ones exhibiting weak anti-inflammatory activity (IC50 > 50 μM). As for hepatoprotective activity assay, compound 1 exhibited more significant activity (inhibition rate of 30.7%) than that of the positive control (bicyclol, inhibition rate of 27.2%), and compounds 4, and 6 showed nearly the same activities as the control (inhibition rates of 26.7% and 25.9%, respectively), with the other ones exhibiting weak hepatoprotective activity.