Triterpenoid saponins from the herb Hylomecon japonica

Six undescribed triterpenoid saponins, named as hylomeconoside C-H, were isolated from the EtOH extract of Hylomecon japonica. On the basis of spectroscopic and chemical evidence, their structures were identified as 3-O-β-D-galactopyranosyl-(1 → 2)-β-D-glucuronopyranosyl gypsogenin 28-O-α-L-rhamnopyranosyl-(1 → 2)-β-L-arabinopyranoside; 3-O-β-D-galactopyranosyl-(1 → 2)-β-D-glucuronopyranosyl gypsogenin 28-O-β-D-xylopyranosyl-(1 → 4)-α-L-rhamnopyranosyl-(1 → 2)-β-L-arabinopyranoside; 3-O-β-D-galactopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-β-D-glucuronopyranosyl gypsogenin 28-O-β-D-glucopyranosyl-(1 → 3)-[β-D-xylopyranosyl-(1 → 4)]-α-L-rhamnopyranosyl-(1 → 2)-β-L-arabinopyranoside; 3-O-β-D-galactopyranosyl-(1 → 2)-β-D-glucuronopyranosyl gypsogenin 28-O-β-D-galactopyranosyl-(1 → 3)-[β-D-xylopyranosyl-(1 → 4)]-α-L-rhamnopyranosyl-(1 → 2)-β-D-fucopyranoside; 3-O-α-L-rhamnopyranosyl-(1 → 3)-[β-D-galactopyranosyl-(1 → 4)]-β-D-glucuronopyranosyl quillaic acid 28-O-β-D-galactopyranosyl-(1 → 3)-[β-D-xylopyranosyl-(1 → 4)]-α-L-rhamnopyranosyl-(1 → 2)-β-D-fucopyranoside; 3-O-α-L-rhamnopyranosyl-(1 → 3)-[β-D-galactopyranosyl-(1 → 4)]-β-D-glucuronopyranosyl quillaic acid 28-O-β-D-xylopyranosyl-(1 → 3)-β-D-xylopyranosyl-(1 → 4)-α-L-rhamnopyranosyl-(1 → 2)-β-D-quinovopyranoside. The 50% EtOH extract showed moderate inhibitory activity on the human cancer cell line HeLa, HepG-2, MCF-7, A549, K562 and TE-1. And these six compounds were tested for cytotoxicity against K562. Among them, hylomeconoside H was found to be the most active on the K562 cell lines (IC₅₀ 6.60 μM).