Antibacterial activity of scleractinian corals in Okinawa, Japan

Most scleractinian corals build coral reef comu­ nities with other corals and microorganisms such as bac­ teria, including pathogenic species. The existence of a chemical defense system to prevent bacterial infection has been suggested by several researchers. We conducted anti bacterial screening of MeOH extracts from scle rac­ tinian coral tissues collected in Okinawa, Japan using 2 strains of gram­positive bacteria (Bacillus subtilis and Staphylococcus aureus) and 4 strains of gram­negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Serratia marcescens, and Vibrio harveyi). All 24 scler­ actinian coral samples had antibacterial activity against S. aureus. Extracts of Montipora digitata and M. informis possessed antibacterial activity against S. aureus and B. subtilis. Isolation and identification of antibacterial prin­ ciples from Montipora digitata was performed using NMR and MS spectra. Antibacterial compounds were identified as known polyacetylene carboxylic acids, mon­ tiporic acids A and C. Partial separation was performed on the tissue of Acropora pulchra and the antibacterial ac­ tivity was found in hydrophilic fraction.