Two new triterpene saponins from Cyclamen africanum Boiss. & Reuter

Two new oleanane-type triterpene saponins, afrocyclamins A and B (1 and 2, resp.), were isolated from a MeOH extract of the roots of Cyclamen africanum Boiss. & Reuter, together with three known triterpenoid saponins, lysikokianoside, deglucocyclamin I, and its dicrotalic acid derivative. The structures were elucidated, on the basis of 1D- and 2D-NMR experiments and mass spectrometry as (3β,20β)-13,28-epoxy-16-oxo-3-{O-β-D- xylopyranosyl-(1→2)-O-β-D-glucopyranosyl-(1→4) -O-[β-D-glucopyranosyl-(1→2)]-α-L-arabinopyranosyl}oxy} oleanan-29-al (1) and (3β,16α,20β)-16,28,29-trihydroxy-olean-12- en-3-yl O-4-O-(4-carboxy-3-hydroxy-3-methyl-1-oxobutyl)-β-D-xylopyranosyl- (1→2)-O-β-D-glucopyranosyl-(1→4)-O-[β-D-glucopyranosyl- (1→2)]-α-L-arabinopyranoside (2).