Monodesmosidic oleanene-type saponins from kidney vetch (Anthyllis vulneraria L.) with hemolytic activity

Abstract Two undescribed monodesmosidic oleanene-type saponins, namely 3β-O-{[β-D-glucopyranosyl-(1→4)]-α-L-arabinopyranosyl}-saikogenin G (1) and 3β-O-{[β-D-glucopyranosyl-(1→4)]-α-L-arabinopyranosyl}-16-deoxysaikogenin F (2), named anthylloside A and B, have been isolated from an acetone-water extract from aerial parts of kidney vetch (A. vulneraria L.). Isolation of 1 and 2 was achieved by solvent partition with EtOAc and subsequent repeated chromatographic purification. The structures of the isolated compounds were elucidated by spectrometric (HR-MS) and spectroscopic methods (1H- and 13C-NMR, UV, IR and CD), as well as GC–MS analysis of samples after 1 N HCl hydrolysis and subsequent derivatization. The configuration and conformation of both 1 and 2 were assigned by means of comprehensive 2D-NMR analyses including 1H-1H−COSY, ROESY, decoupled gHSQC, gHMBC and selective 1D-TOCSY experiments. Moreover, 1 and 2 possess significant hemolytic activity, which was assessed in a blood agar assay and compared to that of three reference saponins.