A new tirucallane-type triterpene from the gum resin of Boswellia carterii

Two compounds were isolated from 95% ethanol extract of the gum resin of Boswellia carterii by silica gel column chromatography (CC) and high-performance liquid chromatography (HPLC). Their structures were identified with IR, UV, NMR and HR-ESI-MS spectroscopic data as 7α-hydroxy-3,11-dioxo- tirucalla-8,24-dien-21-oic acid (1) and 21β-hydroxy-3-acetyl-11-keto-β-boswellic acid (2). In addition, their absolute configurations were also identified by ECD calculations. Among them, compound 1 is a new compound and the absolute configuration of compound 2 is confirmed by ECD calculation for the first time.