Starfish Saponins, Part 49. New Cytotoxic Steroidal Glycosides from the Starfish Fromia monilis

Abstract

Nine new cytotoxic steroidal glycosides 1-9 have been isolated from the starfish Fromia monilis collected off New Caledonia. Structures of these compounds, which include four mono-(1-4), two di-(5,6), and three glycosides (7-9), were elucidated through spectral interpretation. Monilosides G [7], H [8], and I [9] are the first tri-glycosides to be found among the group of glycosides of polyhydroxilated steroids from starfishes.

Chemical Constituents and Bioactivities of Starfish

“…Monilisides G -I (268 -270, resp.) were the first series of steroidal triglycosides isolated from starfish [85]. Solasteroside S 2 (271) was obtained from the starfish Solaster dawsoni in the Sea of Okhotsk [86].…”

“…New cytotoxic steroidal glycosides monilosides A and B (367 and 368, resp.) were isolated from the Caledonian starfish Fromia monilis [85].…”

“…Cytotoxic steroidal glycosides monilosides C and D (404 and 405, resp.) were isolated from the Caledonian starfish Fromia monilis [85]. The Caribbean starfish Echinaster brasiliensis yielded glycosides 406 -411 [111].…”

“…However, nowadays it only represents a number of well-defined structural molecules, which include an aglycone with 9,11-didehydro3b,6a-dihydroxy steroidal nucleus, a sulfate group at C(3), and generally a side chain with the 20b-OH and 23-oxo functions. The oligosaccharide chain, commonly made up of five or six sugar units with b-oriented structure, and sometimes containing also three or four sugar units [85], is always glycosidically linked at C(6). Most of the structural diversity is confined to the substitution pattern of the side chain.…”

Structural Determination of Saponins Extracted from Starfish by Fast Atom Bombardment Collision-Induced Dissociation Mass Spectrometry

“…The glycosides of polyhydroxysteroids are widely distributed in starfish as one of saponins and consist of a steroidal aglycone linked to one or two sugar moieties in both sulfated and non-sulfated forms. [10][11][12][13][14][15][16] To study the structure of small amounts of saponins extracted from plants and marine animals, researchers have applied several analytical methods. Although NMR methods have successfully been used, the utility of NMR is limited due to the amount of material required for NMR analyses.…”