Antifungal nortriterpene and triterpene glycosides from the sea cucumber Apostichopus japonicus Selenka

Article abstract of DOI:10.1016/j.foodchem.2011.10.080

A nortriterpene glycoside, 26-nor-25-oxo-holotoxin A₁ (1), four triterpene glycosides, including both holostane and non-holostane types analogues, holotoxins D-G (2-5), together with three known triterpene glycosides, holotoxins A₁ and B (6, 7), and cladoloside B (8), were isolated from the warty sea cucumber Apostichopus japonicus Selenka, a traditional tonic with high economic value in China. The structures of the new compounds were elucidated by a combination of detailed spectroscopic analysis and chemical methods. This is the first report of a nortriterpene glycoside isolated from sea cucumbers. These compounds showed potent antifungal activities in the in vitro biotest. A preliminary structure-activity analysis suggests that the 18(20) lactone group and the Δ²⁵ terminal double bond may increase the activity. The component of the carbohydrate chain seems play an important role whereas the double bond transformation from Δ ⁹⁽¹¹⁾ to Δ⁷ in the aglycone moiety contributes little to the bioactivity.