Marine antifouling agents based on bioactive compounds isolated from Red Sea soft corals Sarcophyton glaucum and Sclerophytum leptoclados

Abstract

Biofouling starts by the formation of a biofilm consisting of bacteria, diatoms seaweed or phytoplankton. Unfortunately, the adhering of the biofouling organisms’ causes serious problems to the marine industry. The present study examined soft corals collected from Hurghada’s Egyptian Red Sea coast as a source for antifouling agents. Bioactive compounds, specifically 8-epi-sarcophinone and ent-sarcophine, were extracted from Sarcophyton glaucum, whereas Alismol and Gorgosterol were obtained from Sclerophytum leptoclados. Their structural analyses were investigated using 1H and 13C NMR spectra. The biocidal weights (10 mg in 10 g) of paint formulations were executed to unprimed steel and then submerged for 215 days in the water of the Eastern Harbor (E.H.) of Alexandria, Egypt. Additionally, the hydrographic properties of seawater were determined. The results showed that all paint formulations exhibited good antifouling properties. After 215 days of immersion, the steel panels coated by Gorgosterol, 8-epi-sarcophinone, and ent-sarcophine demonstrated the best performance against fouling organisms. The steel-coated panel containing Gorgosterol showed only 1% tubeworms, 8-epi-sarcophinone had 5% barnacles and 1% tubeworms, while ent-sarcophine showed 3% barnacles and 10% tubeworms. Overall, the results indicated that natural compounds have the potential to serve as effective and environmentally friendly alternatives to synthetic compounds in antifouling paint formulations.

Keywords

• Sarcophyton glaucum
• Sclerophytum leptoclados
• Antifouling paints
• Hydrographic parameters