Synthesis and cytotoxic activity of boswellic acid analogues

Publication date: December 2016 Source:Phytochemistry Letters, Volume 18 Author(s): Peihong Fan, Tao Li, Yaqing Ye, Qian Luo, Huiqing Yuan, Hongxiang Lou Fifteen stereoisomers of boswellic acid analogues bearing 2-OH, 24-OH, 3-keto or 2-OH, 3-OH, 24-OH groups were synthesised and their structures were confirmed using 1H NMR, 13C NMR, 2D NMR and HRMS. The cytotoxic activities of these compounds toward three human tumor cell lines, K562, PC3 and A549, were evaluated. Preliminary biological evaluation indicated most of these compounds exhibited cytotoxic activity comparable to that of 3-O-acetyl-11-keto-β-boswellic acid (AKBA). Notably, several analogues exhibited relatively stronger cytotoxicity, with IC50 values less than 10μM against A549 and PC3 cell lines. For the 24-OH series of BAs analogues, structure-activity relationship (SAR) analysis indicated that the stereochemical configurations of compounds incorporating 2-OH, 3-keto or 2-OH, 3-OH group pairs could not predictably or markedly impact cytotoxic activity, except when 2β-OH and/or 3β-OH were present. Esterification of 2-OH, 3-OH and 24-OH groups tended to decrease cytotoxicity. Graphical abstract

Source: Phytochemistry Letters - September 29, 2016 Category: Chemistry Source Type: research