Biologically active triterpenoids from Cephalaria ambrosioides

Abstract

The roots of Cephalaria ambrosioides yielded a new triterpene, 6α-hydroxyhederagenic acid (1), in addition to the known triterpene hederagenic acid (2) and four corresponding saponins, leontoside A (or akeboside Stb) (3), kalopanax saponin A (or α-hederin) (4), saponin PG (or sapindoside B) (5), and dipsacoside B (6). Their structures have been elucidated on the basis of their spectral data (MS, 1 D and 2 D NMR) and by some chemical transformations. The extract and all isolated compounds were evaluated for their antimicrobial, molluscicidal and in vitro cytotoxic activities. All compounds showed strong antimicrobial activity (MIC values 1.80-2.50 μg/mL), with 5 and 6 exhibiting activities comparable to those of standard antibiotics. Moreover, compounds 3-5 were active against all assayed cancer cell lines, whereas compounds 3 and 4 exhibited higher activities against Biomphalaria glabrata snails, with minimum inhibitory concentrations of 5.4 and 6.2 μg/mL, respectively. © Georg Thieme Verlag KG Stuttgart