Cytotoxic saponins from the root of Dipsacus asper Wall.

Cytotoxic activitiy of seven hederagenin saponins isolated from the root of Dipsacus asper were investigated in vitro against L1210, HL-60 and SK-OV-3 tumor cell lines by the MTT method. 3-O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl hederagenin (2), 3-O-beta-D-xylopyranosyl-(1-->3)-alpha-L-Rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl hederagenin (6) and 3-O-beta-D-glucopyranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl hederagenin (7) exhibited the potent cytotoxicity against the three tumor cell lines with IC50 values ranging from 4.7 to 8.7 microg/mL, with the exception of compound 7, which exhibited weak cytotoxic activity against SK-OV-3 (IC50 22.5 microg/mL). Other compounds did not exhibit any cytotoxic activity (IC50 > 30 microg/mL).