en Biotechnology Biotechnology پژوهشي Orginal research papers <p><span style="font-size:11pt"><span style="tab-stops:109.5pt"><span style="line-height:115%"><span style="font-family:Calibri,sans-serif"><span style="font-size:11.5pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times=""><span style="color:black">In search for bioactive products, three zoanthid species (<i>Zoanthus </i>spp<i>.</i>,<i> Palythoa tuberculosa and Palythoa mutuki)</i> were collected from offshore zone of Hengam Island. Three extracts of each zoanthids (methanol, dichloromethane (DCM) and n-hexane) were tested for antifungal and antibacterial activities against certified strains of bacteria (two Gram-positive: <i>Bacillus</i></span></span></span></span><b><i> </i></b><i><span style="font-size:11.5pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times=""><span style="color:black">subtilis</span></span></span></span></i><span style="font-size:11.5pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times=""><span style="color:black">, <i>Staphylococcus aureus </i>and three Gram-negative: <i>Escherichia coli</i>, <i>Pseudomonas aeruginosa</i>,</span></span></span></span> <i><span style="font-size:11.5pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times=""><span style="color:black">Proteus</span></span></span></span></i><span style="font-size:11.5pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times=""><span style="color:black"> <i>vulgaris</i>) and fungi (<i>Candida albicans</i>, <i>Microsporum gypseum</i>, <i>Microsporum canis</i>) through the disk diffusion assay. Cytotoxic activity of these extracts was evaluated against <i>Artemia</i> nauplii. The results showed that 8 extracts (88.88%) of the zoanthids were active against at least one bacterial strain and 6 extracts (66.6%) were active against at least one fungus (the activity against bacteria was moderate). Also, minimum inhibitory concentrations (MICs) of the extracts with desirable (inhibition zone more than 9mm) in the previous stage were assessed. Among the 9 zoanthids extract, 88.88% showed activity against some of the five bacteria, and 66.6% showed activity against some of the three fungi. The most active zoanthid extract against three fungi was dichloromethane extract of the <i>Zoanthus </i>ssp. that showed promising antifungal activity against <i>Candida albicans in vitro</i> models. The minimum inhibitory concentrations and LC₅₀ values of dichloromethane extract of <i>Zoanthus </i>ssp were 125&mu;g/mL and 181&mu;g/mL, respectively. Therefore, this extract can be a candidate for candidiasis therapy. &nbsp;LC₅₀ of DCM, crude extract of <i>Palythoa mutuki </i>was 31&micro;g/ml, showing high toxicity. This is the first report of biological activities of marine zoanthids from an Iranian Island of Persian Gulf.</span></span></span></span></span></span></span></span></p> <p></p> Zoanthids, Antifungal activity, Antimicrobial activity, Cytotoxic activity, Hengam Island, Persian Gulf 1004 1016 http://jifro.ir/browse.php?a_code=A-10-2405-1&slc_lang=en&sid=1 S.S. Eisapoor eisaporsahand@yahoo.com 100319475328460046471 100319475328460046471 Yes Pasteur Institute of Iran Sh. Safaeian 100319475328460046472 100319475328460046472 No Department of Marine Biology, Islamic Azad University, North Tehran Branch, Tehran, Iran A. Mahmoodzadeh 100319475328460046473 100319475328460046473 No Department of Biology, Islamic Azad University, Roudehen Branch, Roudehen, Iran