Two new bioactive triterpene glycosides from the sea cucumber Pseudocolochirus violaceus

By activity-guided fractionation, two new triterpene glycosides, violaceusides A (1) and B (2), were isolated from the sea cucumber Pseudocolochirus violaceus as active compounds causing morphological abnormality of Pyricularia oryzae mycelia. By extensive 2D NMR techniques and chemical evidence, the structures of the two new glycosides were established as 16β-acetoxy-3- O -[3- O -methyl-β-d-glucopyranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 4)-β-d-quinovopyranosyl-(1 → 2)-4- O -sodiumsulphate-β-d-xylopyranosyl]-holosta-7,24-diene-3β-ol (1) and 16β-acetoxy-3- O -[3- O -methyl-β-d-glucopyranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 4)-β-d-glucopyranosyl-(1 → 2)-4- O -sodiumsulphate-β-d-xylopyranosyl]-holosta-7,24-diene-3β-ol (2), respectively. The two glycosides also exhibited significant cytotoxicity against HL-60 and BEL-7402 cancer cell lines.