Characteristic cembrane-type diterpenoids with nitric oxide inhibitory activity from the gum resin of Boswellia carterii Birdw.

Five new characteristic cembrane-type diterpenoids (olibacartiols A–E, 1 – 5) were acquired from the gum resin of Boswellia carterii. The structures of these diterpenoids were characterized by detailed spectroscopic analysis, and compounds 1 – 3 were unambiguously confirmed by single-crystal X-ray diffraction experiments. The anti-inflammatory activities of the isolated compounds were evaluated using LPS-induced BV2 cell model and compounds 2 – 5 showed moderate NO inhibitory effects with IC 50 values of 8.84 ± 1.02, 9.82 ± 1.95, 9.75 ± 2.24, and 7.39 ± 1.24 μM, respectively. [Display omitted] • Five undescribed cembrane-type diterpenoids were acquired from the gum resin of Boswellia carterii. • Their structures were characterized by spectroscopic analysis, ECD calculations, and X-ray diffraction experiments. • Compounds 2 – 5 showed moderate anti-inflammatory effects on LPS-induced BV2 cell. [ABSTRACT FROM AUTHOR]