The Chemical Constituents and Structure-antifouling-activity Relationships of PAEs from Marine Organisms

The PAEs from the gorgonian Anthogorgia caerulea,and the ethyl acetate extract of the culture broth of Bacillus subtilis and Cladosporium sp. were isolated and purified by chromatography on silica gel,sephadex LH-20 columns,and HPLC and structurally identified by spectral analysis. Eight compounds were identified as di-( 2-ethylhexyl)phthalate( 1),2-O-butyl-1-O-( 2'-ethylhexyl) benzene-1,8-dicarboxylate( 2),di-( 2-propylpentyl) phthalate( 3),dibutyl phthalate( 4),diisobutyl phthalate( 5),bis( 2-ethylbutyl) phthalate( 6),bis( 2-ethylnonyl) phthalate( 7),bis( 2-ethyldecyl) phthalate( 8). Compound 2 previously isolated from terrestrial organism but first obtained as marine natural product,and the other compounds were isolated from Anthogorgia caerulea,Bacillus subtilis,and Cladosporium sp. for the first time except 6. The antilarval activity of compound 1-8 was evaluated in settlement inhibition assay with laboratoryreared Balanus amphitrite( Cirripedia) larvae. The most potent metabolites produced by Cladosporium sp. were bis( 2-ethyldecyl) phthalate( EC50= 1. 93 ± 0. 93 μg / mL). The lipophilicgroup,side-chain fatty,and branched-chain fatty were very inhibitive to the larval settlement in the tube-building B. amphitrite larvae.