Antibacterial effect of the red sea soft coral <i>Sarcophyton trocheliophorum</i>

<div><p>The marine soft corals <i>Sarcophyton trocheliophorum</i> crude extracts possessed antimicrobial activity towards pathogenic bacterial strains, i.e. <i>Bacillus cereus</i>, <i>Salmonella typhi, Escherichia coli, Staphylococcus aureus</i> and <i>Pseudomonas aeruginosa</i>. Bioassay-guided fractionation indicated that the antimicrobial effect was due to the presence of terpenoid bioactive derivatives. Further biological assays of the <i>n</i>-hexane fractions were carried out using turbidity assay, inhibition zone assay and minimum inhibitory concentration for investigating the growth-inhibition effect towards the Gram-positive and Gram-negative bacteria. The fractions were screened and the structure of the isolated compound was justified by interpretation of the spectroscopic data, mainly mass spectrometry (GC-MS). The structure was assigned as (5<i>S</i>)-3-[(3<i>E</i>,5<i>S</i>)-5-hydroxy-3-hepten-6-yn-1-yl]-5-methyl-2(5H)-furanone and was effective at concentrations as low as 0.20 mg/mL. The above findings, in the course of our ongoing research on marine products, may implicate that the profound anti-microbial activity of the <i>S. trocheliophorum</i> soft corals, inhabiting the red sea reefs, is attributed to the presence of growth-inhibiting secondary metabolites mainly terpenoids.</p>