Three compounds were isolated from the fraction of monosulfated triterpene glycosides from Cucumaria okhotensis, a new sea cucumber species, and their structures were elucidated. First of them, okhotoside A1-1, is a new glycoside containing tetrasaccharide sugar moiety; the second, okhotoside A2-1, is a new pentaoside with a glucose residue in the second position of sugar moiety (such a structural peculiarity has been found in holothurians of the genus Cucumaria for the first time); and the third is a previously known pentaoside cucumarioside A0-1 from C. japonica. The species-specificity of the triterpene glycosides from C. okhotensis was revealed, which justifies the description of this sea cucumber as a new species.
