Abstract
Soft corals are considered as a prospective resource for the isolation of natural product antifoulants. In this study, the temporal variations in the antifouling activity of the crude extract of the soft coral Sarcophyton trocheliophorum samples collected from the Jeddah coast of Saudi Arabia during summer (June-August 2018) and winter seasons (December 2018-February 2019) were assessed using laboratory tests. The crude extract was tested against biofilm-forming bacteria and barnacle larvae in the laboratory. The results indicated significant variations (P < 0.001) in the antifouling activity of the extracts between the samples collected during the summer and winter seasons. The extract of the soft coral samples collected during the summer season showed higher inhibitory activity against the fouling bacteria and barnacle larva. In addition, the surface-associated bacteria abundance on the soft corals were analysed and the results showed higher abundance on winter season samples. Further, GC-MS analysis indicated differences in the metabolite composition with the abundance of compounds such as cis-z-a-Bisabolene epoxide and caryophyllene oxide being high in summer samples and Isoaromadendrene epoxide and beta-cembrenediol showing a higher peak area percentage in winter samples. Overall, this study revealed temporal variations in the antifouling activity and metabolite composition of the Red Sea soft corals.