Cytotoxic Cardenolides from the Leaves of Acokanthera oblongifolia

Abstract

AbstractThree previously undescribed cardenolides, acovenosigenin A 3-O-α-L-acofriopyranoside (1), 14-anhydroacovenosigenin A 3-O-[β-D-glucopyranosyl-(1″→4′)-O-α-L-acofriopyranoside] (2), and 14-anhydroacovenosigenin A 3-O-[β-D-glucopyranosyl-(1″→4′)-O-α-L-acovenopyranoside] (3), together with the two already known ones, 14-anhydrodigitoxigenin 3-O-β-D-glucopyranoside (4) and acospectoside A (5), were isolated from the leaves of Acokanthera oblongifolia. The influence of cardenolides 1 – 3 and acovenoside A (found in the Acokanthera genus) on three cancer cell lines (HT29, HCT116, and AGS) was also investigated. The most promising results, in comparison with oxaliplatin, were obtained for compound 1, which was found to be highly cytotoxic for all tested cell lines, HT29 (IC50 = 63.49 nM), HCT116 (IC50 = 67.35 nM), and AGS (IC50 = 80.92 nM). Unfortunately, 1 also showed similar toxicity towards normal lymphocytes (IC50 = 98.03 nM).