Analysis of saponins as bioactive zoochemicals from the marine functional food sea cucumber Bohadschia cousteaui

The edible portion of sea cucumber, body walls, is a source of natural bioactive compounds. Triterpene saponins are the main chemical constituents in sea cucumber that have potential interest for the body health and food industry. Twenty-one lanostane-type non-sulphated triterpene glycosides were isolated from the methanol/methylene chloride extract of the body walls of Bohadschia cousteaui. Ten new saponins called coustesides A (1), B (3), C (9), D (10), E (11), F (12), G (15), H (16), I (17) and J (18), including two pentasaccharide and eight hexasaccharide saponins, together with eleven known triterpene glycosides, were isolated by reversed-phase semi-preparative HPLC. Their structures were mainly determined by 1D- and 2D-NMR (H-1, C-13, COSY, TOCSY, HSQC, HMBC and ROESY) as well as MS experiments and acid hydrolysis. Most of the isolated compounds showed good antifungal activity against Candida albicans. Moreover, sea cucumber B. cousteaui is a rich source of biologically active saponins. Therefore, sea cucumbers are eaten for their therapeutic values as a functional food than for their seafood taste.