Cytotoxic triterpene saponins from the leaves of Aralia elata.

Phytochemical investigation of the leaves of Aralia elata has led to the isolation of four new compounds, 3-O-β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl oleanolic acid (1), 3-O-[β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl (1→3)]-[β-D-glucopyranosyl (1→2)]-β-d-glucopyranosyl hederagenin 28-O-β-D-glucopyranoside (2), 3-O-{[β-D-glucopyranosyl (1→2)]-[β-d-glucopyranosyl (1→3)-β-d-glucopyranosyl (1→3)]-β-D-glucopyranosyl} oleanolic acid 28-O-β-D-glucopyranosyl ester (3) and 3-O-[β-D-glucopyranosyl (1→2)]-[β-D-glucopyranosyl (1→3)]-β-d-glucopyranosyl caulophyllogenin (4) and two known compounds, 3-O-[β-D-glucopyranosyl (1→3)-α-l-arabinopyranosyl]-echinocystic acid (5) and 3-O-α-L-arabinopyranosyl echinocystic acid (6). The structural determination was accomplished with spectroscopic analysis, in particular (13)C-NMR, 2D-NMR and HR-ESI-MS techniques. Compounds 1-6 were tested for their inhibition of the growth of HL60, A549 and DU145 cancer cells. Compound 1 showed significant cytotoxic activity against HL60 and A549 cancer cells with IC(50) values of 6.99μM and 7.93μM respectively. In addition, compounds 5 and 6 showed significant cytotoxic activity against HL60 cancer cells with IC(50) values of 5.75μM and 7.51μM, respectively.