New triterpenoid saponin from the stems of Albizia adianthifolia (Schumach.) W.Wight.

As part of our continuing study of apoptosis-inducing saponins from Cameroonian Albizia genus, one new triterpenoid saponin, named adianthifolioside J (1), together with the known gummiferaoside E (2), were isolated from Albizia adianthifolia stems. The structure of the new saponin (1), was established on the basis of extensive analysis of 1 D and 2 D NMR (1H-, 13C-NMR, DEPT, COSY, TOCSY, NOESY, HSQC, HSQC-TOCSY and HMBC) and HRESIMS experiments, and by chemical evidence as 3-O-[ß-D-xylopyranosyl-(1→2)-ß-D-fucopyranosyl-(1→6)-ß-D-glucopyranosyl]-21-O-{(2E,6S)-2-(hydroxymethyl)-6-methyl-6-O-{4-O-[(2E,6S)-2,6-dimethyl-6-O-(ß-D-quinovopyranosyl)octa-2,7-dienoyl]-(ß-D-quinovopyranosyl)octa-2,7-dienoyl]}acacic acid-28-O-ß-D-glucopyranosyl-(1→3)-[5-O-acetyl-α-L-arabinofuranosyl-(1→4)]-α-L-rhamnopyranosyl-(1→2)-ß-D-glucopyranosyl ester (1). The pro-apoptotic activity of the new isolated saponin 1 was evaluated, using Annexin V-FITC binding assay, on the A431 human epidermoid cancer cell. The result showed that adianthifolioside J (1) displayed weak pro-apoptotic activity.