Biological Activities of Different Sponge Extracts

Over the last few years, samples from the marine environment have been investigated for different metabolites with interesting biological activities. Marine sponges, from which more than 50% of marine natural compounds have been isolated, are a rich source of compounds with citotoxic and antitumor properties. The antioxidant activity of compounds isolated from marine sponges is poorly studied. Aqueous extracts of different sponge species (Smenospongia sp., Axinelta corrugata, Cinachyrella sp., Svenzea flava, Plakortis simplex, Ircina felix, Piylocaulis sp, Tedania ignis) were screened for antioxidant power using three different assays: DPPH (1,1 -diphenyl-2-picrylhydrazy) radical scavenging, Ferric Reducing Antioxidant Power (FRAP) and β-carotene bleaching (BCB) test. Results showed as Plakartis simplex extract possesses the highest ferric reducing antioxidant power, lipid peroxidation inhibition capacity and the lowest IC50 value. This results are consistent also with the high “putative phenolic” content shown by Folin-Ciocalteu test. A considerable biological activity was also observed for lrcinafelìx, Axinella corrugata, and Cinachyrella extracts, even if their activities in the different tests was not directly comparable, and not positively related with results obtained by Folin-Ciocalteu method. In fact the correlation (R2 index) among all antioxidant tests was low (data not shown), suggesting that extract compositions may be signifìcantly different and that it is connected with extract specifie biological activity. Further studies will be focused on developing standardized methods for antioxidant determination in marine sponges and on identification of marine antioxidant compounds mainly responsible for the biological activity.