Four new triterpenoid saponins from Polygala crotalarioides / 中草药

ABSTRACT

Objective: To study the chemical constituents of Polygala crotalarioides. Methods: The compounds were isolated by silica gel, RP-18, Sephadex LH-20 column chromatography, and semi-pre HPLC. Their structures were elucidated on the basis of spectral analysis and chemical evidence. Results: Four oleanane-type saponins were isolated from the roots of P. crotalarioides. Their structures were elucidated as 3-O-β-D-glucopyranosyl presenegenin 28-O-β-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→3)]-β-D-fucopyranoside (1), 3-O-β-D-glucopyranosyl presenegenin 28-O-β-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-[6-O-acetyl-β-D-glucopyranosyl-(1→3)]-[4-O-(E/Z)-4″-mehoxycinnamoyl]-β-D-fucopyranoside (2), 3-O-β-D-glucopyranosyl presenegenin 28-O-β-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-[6-O-acetyl-β-D-glucopyranosyl-(1→3)]-[4-O-(E/Z)-3″, 4″-dimethoxycinnamoyl]-β-D-fucopyranoside (3), and 3-O-β-D-glucopyranosyl presenegenin 28-O-β-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-[6-O-acetyl-β-D-glucopyranosyl-(1→3)]-[4-O-(E/Z)-3″, 4″, 5″-trimethoxy-cinnamoyl]-β-D-fucopyranoside (4), respectively. Conclusion: Compounds 1-4 are new compounds named crotalarioside C, (E/Z)-crotalariosides D, E, and F, respectively. Among them, compounds 2-4 are cis-trans-isomers, which can not be separated by the experimental technique because of the configuration.