Saponin and sapogenol. XV. Antifungal glycosides from the sea cucumber Stichopus japonicus Selenka. (2). Structures of holotoxin A and holotoxin B.

The structure of holotoxin A, the major antifungal glycoside isolated from the Far Eastern sea cucumber Stichopus japonicus SELENKA, has been elucidated as 4 on the bases of chemical and physicochemical evidence and enzymatic hydrolysis. Holotoxin B (14), a minor antifungal glycoside of the same origin, has been suggested to be the glucoside of holotoxin A (4) on the similar basis. Holotoxin C, another minor glycoside, has been suggested to be the similar type of glycoside as holotoxin A and B. Holotoxin A and B are distinctive by the possession of two α-linkages of D-xylose and D-quinovose in the oligosaccharide portion. Finally, comparison of the anti-microbial activity of holotoxins with the various kinds of saponins isolated from the plant materials has been presented.