Structures of cucumariosides C1 and C2 — Two new triterpene glycosides from the holothurian Eupentacta fraudatrix

Two new triterpene glycosides — cucmariosides C₁ and C₂ — have been isolated from the Far Eastern holothurianEupentacta (=Cucumaria)fraudatrix Djakonov et Baranova. Their structures have been established with the aid of¹³C NMR and PMR spectroscopy, partial acid hydrolysis, periodate oxidation, and methylation as 16β-acetoxy-3-{[3-O-methyl-β-D-xylopyranosyl-(1→3)-β-D-glucopyranosyl-(1→4)] [β-D-xylopyranosyl-(1→2)]-β-D-quinovopyranosyl-(1→2)-β-D-xylopyranosyloxy}holosta-7,23,24(cis)-triene and 16β-acetoxy-3-{[3-O-methyl-β-D-xylopyranosyl-(1→3)-β-D-glucopyranosyl-(1→4)] [β-D-xylopyranosyl-(1→2)]-β-D-quinovopyranosyl-(1→2)-β-D-xylopyranosyloxy}holosta-7,22,24(trans)-triene, respectively.