Antibacterial activities of anthozoan corals on some marine microfoulers

The antibacterial activities of twelve species of anthozoans (4 gorgonians, 5 soft corals and 3 antipatharians) collected off the east coast of India were assayed against four dominant marine fouling bacterial strains isolate d from the biofilm of fouled aluminium panels. Of the 48 combinations (12 c orals x 4 bacteria) eighteen interactions showed antibacterial activity (37 .5%). Such activity was most apparent in gorgonians, which inhibited bacter ial growth in ten out of sixteen interactions (62.5%) compared with that of five out of twenty interactions (25%) among soft corals and three out of t welve interactions (25%) among antipatharians. The activity scores varied w ith different extracts and test organisms used, and was highest in antipath arians. Among the four bacterial strains Vibrio sp. was the least sensitive (2/12) when compared with Flavobacterium sp. (6/12). This is the first rep ort of antibacterial activities of antipatharian colonies against marine mi crofoulers. The results imply that anthozoan corals harbour potent agents w hich could be exploited for the development of antifouling technology.