Anti-inflammatory and hepatoprotective cembranes from the gum resin of Boswellia carterii

Three undescribed cembrane type diterpenoids, boscartins AX-AZ (1-3) were discovered from the gum resin of Boswellia carterii. Their structures were elucidated by analyzing the spectroscopic data. Notably, all these three compounds preserved an isopropyl type cembranoid skeleton, featured the same groups of one epoxy ring at C-1-C-12 and one hydroxy group at C-11, as well as an epoxy ring migrating from C-6-C-7 to C-3-C-4. These cembranoids were evaluated for the hepatoprotective and anti-inflammatory activities using two cell models of APAP-induced HepG2 and LPS-induced RAW 264.7. Results showed that compound 1 displayed remarkable hepatoprotective activity at 10 mu M (inhibition rate of 47.81 %) and significant anti-inflammatory activity (IC50 of 2.39 mu M), with the other two compounds (2 and 3) giving less potently biological activities.