Triterpene saponins from Eryngium campestre

Five new triterpene saponins, 3-O-alpha-L-rhamnopyranosyl-(1 -> 2)-beta-D-glucuronopyranosyl-22-O-beta,beta-dimethylacryloyl-A1-barrigenol (1), 3-O-alpha-L-rhamnopyranosyl-(1 -> 2)-beta-D-glucuronopyranosyl-22-O-angeloyl-R1-barrigenol (2), 3-O-alpha-L-rhamnopyranosyl-(1 -> 2)-beta-D-glucuronopyranosyl-21-O-acetyl-22-O-angeloyl-R1-barrigenol (3), 3-O-alpha-L-rhamnopyranosyl-(1 -> 2)-beta-D-glucuronopyranosyl-21-O-acetyl-22-O-beta,beta-dimethylacryloyl-R1-barrigenol (4), and 3-O-alpha-L-rhamnopyranosyl-( 1 -> 2)-beta-D-glucuronopyranosyl-22-O-angeloyl-28-O-acetyl-R1-barrigenol (5), were isolated from the roots of Eryngium campestre. Their structures were established mainly by 2D NMR techniques and mass spectrometry. Compounds 1-4 and 3-O-beta-D-glucopyranosyl-(1 -> 2)-[alpha-L-rhamnopyranosyl-(1 -> 4)]-beta-D-glucuronopyranosyl-22-O-beta,beta-dimethylacryloyl-A1-barrigenol, previously isolated from the same plant, showed a weak cytotoxicity when tested against HCT 116 and HT 29 human colon cancer cells.