Chemical and Biological Investigation of the Polar Constituents of the Starfish Luidia clathrata, Collected in the Gulf of Mexico

Abstract

Ten new [1-10] and three known [11-13] polyhydroxysteroids were isolated, along with four known asterosaponins [14-17], from the starfish Luidia clathrata, collected from the offshore waters of the northern Gulf of Mexico. The EtOH extracts of this starfish showed feeding-deterrent properties against marine fish, and inhibited the settlement of larvae of barnacles and bryozoans, as well as the growth of several bacteria. The structures of the new compounds were determined by interpretation of their nmr spectral data and by comparison with the spectral data of known compounds. The assignment of the configurations of the side-chain stereogenic centers of compounds 1 and 3-10 were based on the comparison of their nmr data with those of the stereoisomeric model compounds after derivatization with the chiral auxiliary MTPA reagent. Larval settlement assays conducted on ten isolated compounds revealed they are all potent inhibitors of settlement. Two of these isolated compounds inhibited the growth of several bacteria.

Chemical antifouling defences of sea stars: effects of the natural products hexadecanoic acid, cholesterol, lathosterol and sitosterol

“…Based on the results of the present study, the surface-associated compounds hexadecanoic acid, cholesterol and lathosterol of Linckia laevigata, Fromia indica, Cryptasterina pentagona and Archaster typicus are primary metabolites with a secondary function in fouling control. Previous studies on chemical antifouling defences of sea stars have identified the antifouling role of crude extracts and secondary metabolites, such as asterosaponins (Iorizzi et al 1995, De Marino et al 2000, but have not identified any fatty acids or sterols in crude extracts. As primary metabolites, fatty acids and sterols are a source of energy and are structural components of cell membranes that influence membrane properties, such as permeability (Papahadjopoulos et al 1973, Voogt et al 1993.…”

“…Of these, the extract of the sea star Goniaster tesselatus was the most active, reducing the settlement of Balanus amphitrite and Bugula neritina at concentrations of ≥4.8 µg ml -1 (Bryan et al 1996). Similarly, the ethanol whole body extracts of the sea star L. clathrata inhibited the settlement of Balanus amphitrite and Bugula neritina at concentrations of ≥120 and ≥4.8 µg ml -1 , respectively (Iorizzi et al 1995).…”

“…However, mechanical antifouling defences associated with the pedicellariae of the crown-of-thorns sea star Acanthaster planci (Guenther et al 2007b) and physical antifouling defences associated with the wettabilities and surface microtopographies of the sea stars Linckia laevigata, Fromia indica, Cryptasterina pentagona and Archaster typicus (Guenther & de Nys 2007) are inefficient and do not explain how these sea stars keep their surfaces free of fouling organisms. In contrast, crude extracts and isolated compounds from sea star tissues have commonly been tested against selected fouling organisms using disc diffusion assays (Bryan et al 1994, Iorizzi et al 1995, motion analysis assays (Iken et al 2001, Greer et al 2006) and settlement assays (Iorizzi et al 1995, Bryan et al 1996, De Marino et al 2000. Iorizzi et al (1995) demonstrated that the ethanol whole body extracts of the sea star Luidia clathrata inhibited the growth of the bacteria Bacillus subtilis and Staphylococcus aureus.…”

“…In contrast, crude extracts and isolated compounds from sea star tissues have commonly been tested against selected fouling organisms using disc diffusion assays (Bryan et al 1994, Iorizzi et al 1995, motion analysis assays (Iken et al 2001, Greer et al 2006) and settlement assays (Iorizzi et al 1995, Bryan et al 1996, De Marino et al 2000. Iorizzi et al (1995) demonstrated that the ethanol whole body extracts of the sea star Luidia clathrata inhibited the growth of the bacteria Bacillus subtilis and Staphylococcus aureus. Furthermore, spores of the brown alga Hincksia irregularis exposed to low concentrations (< 91 µg ml -1 ) of aqueous and organic body wall extracts of the sea stars Astropecten articulatus and L. clathrata changed their normally fast and straight swimming movements to helical and erratic .…”

Steroids from the Cold Water Starfish Ctenodiscus crispatus with Cytotoxic and Apoptotic Effects on Human Hepatocellular Carcinoma and Glioblastoma Cells

“…Three remaining sterols were determined to be (22E,24R, 25R)-24-methyl-5α-cholest-22-en-3β,5,6β,15α,25,26-hexol 26-O-sulfate (2), 6 (25S)-5α-cholestane-3β,5,6β,15α,16β,26-hexaol (4), 10 and Δ7-sitosterol (5) 11 by comparing their NMR and MS data with those reported in the literature (Figure 1).…”