Brominated Secondary Compounds from the Marine Sponge Verongia aerophoba and the Sponge Feeding Gastropod Tylodina perversa

Abstract

Abstract Analysis of the marine sponge Verongia aerophoba from the Canary islands afforded the brominated secondary constituents isofistularin-3, aerophobin-1 and aerophobin-2 which are probably involved in the chemical defense of the sponge. In addition the yellow pigment uranidine and the unusual sterol aplysterol were isolated. The patterns of brominated compounds were almost superimposable when samples of V. aerophoba from different islands were com­ pared by HPLC indicating de novo synthesis by the sponge or by endosymbiotic microorgan­isms rather than uptake by filter feeding. The only differences observed between the different samples analyzed were with regard to the total concentrations of brominated compounds which varied from 7.2-12.3% of the dry weight dependent on the different collection sites. The Opisthobranch gastropod Tylodina perversa is specialized for feeding on V. aerophoba. Chemical analysis of the gastropod revealed the sponge constituents uranidine, isofistularin-3, aerophobin-1 and aerophobin-2 as well as aerothionin, a further brominated compound which is apparently a biotransform ation product of the brominated sponge constiiuents.