Saponins from the roots of Nylandtia spinosa

From the roots of Nylandtia spinosa, four new triterpene saponins, 3-O-β-D-glucopyranosylpresenegenin 28-O-β-D-galactopyranosyl- (1→4)-[α-L-arabinopyranosyl-(1→3)]-β-D-xylopyranosyl- (1→4)-[β-D-apiofuranosyl-(1→3)]-α-L-rhamnopyranosyl- (1→2)-β-D-fucopyranosyl ester (1), 3-O-β-D- glucopyranosylpresenegenin 28-O-β-D-galactopyranosyl-(1→4)-[α-L- arabinopyranosyl-(1→3)]-β-D-xylopyranosyl-(1→4) -α-L-rhamnopyranosyl-(1→2)-β-D-fucopyranosyl ester (2), 3-O-β-D-glucopyranosylpresenegenin 28-O-β-D-apiofuranosyl-(1→4)- [β-D-galactopyranosyl-(1→2)]-β-D-xylopyranosyl-(1→4) -α-L-rhamnopyranosyl-(1→2)-β-D-fucopyranosyl ester (3), and 3-O-β-D-glucopyranosylpresenegenin 28-O-β-D-apiofuranosyl-(1→3)- β-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2) -β-D-fucopyranosyl ester (4), were isolated, together with the known tenuifolin. Their structures were established mainly by 2D NMR techniques and mass spectrometry. Compounds 1-4 were evaluated for cytotoxicity against HCT 116 and HT-29 human colon cancer cells, but were inactive (IC₅₀ > 5 μg/mL).