Starfish saponins, LVI Three new asterosaponins from the starfish Goniopecten demonstrans

Three new steroidal sulfate pentaglycosides (asterosaponins), goniopectenos ides A-C (1-3), were isolated from the polar extract of the starfish Goniop ecten demonstrans. The pentasaccharide moiety Linked to C-6 of 3 beta -sulf ated steroidal aglycones, consists of D-xylose, D-fucose, D-quinovose, and the unprecedented 3-O-methyl-D-quinovose. The three asterosaponins differ f rom each other in the side chains. Their structures were elucidated by exte nsive NMR experiments including H-1-H-1 (COSY, TOCSY, ROESY) and H-1-C-13 ( HMQC and HMBC) spectroscopy as well as chemical evidence. The isolated aste rosaponins have been found to significantly inhibit the settlement of the b iofouling marine brown macroalga Hincksia irregularis.