CHEMICAL AND BIOLOGICAL INVESTIGATION OF THE POLAR CONSTITUENTS OF THE STARFISH LUIDIA-CLATHRATA, COLLECTED IN THE GULF-OF-MEXICO

Ten new [1-10] and three known [11-13] polyhydroxysteroids were isolat ed, along with four known asterosaponins [14-17], from the starfish Lu idia clathrata, collected from the offshore waters of the northern Gul f of Mexico. The EtOH extracts of this starfish showed feeding-deterre nt properties against marine fish, and inhibited the settlement of lar vae of barnacles and bryozoans, as well as the growth of several bacte ria. The structures of the new compounds were determined by interpreta tion of their nmr spectral data and by comparison with the spectral da ta of known compounds. The assignment of the configurations of the sid e-chain stereogenic centers of compounds 1 and 3-10 were based on the comparison of their nmr data with those of the stereoisomeric model co mpounds after derivatization with the chiral auxiliary MTPA reagent. L arval settlement assays conducted on ten isolated compounds revealed t hey are all potent inhibitors of settlement. Two of these isolated com pounds inhibited the growth of several bacteria.