Evaluation of cytotoxic and antibacterial properties of Symbiodinium sp. isolated and purified from Stichodactyla haddoni in the Persian Gulf and Gulf of Oman

Symbiotic relationships play an important role in marine ecosystems. Among marine symbionts, marine dinoflagellate chemical compounds have drawn the interest of biologists and ecologists due to their rich supplies of unique active secondary metabolites. The aim of this study was to evaluate the cytotoxicity and antibacterial activity of Symbiodinium sp. extract isolated and purified from Stichodactyla haddoni in the Persian Gulf and the Gulf of Oman and purified and cultured Symbiodinium sp. in vitro. Sea anemone samples of S. haddoni were collected during summer and winter and Symbiodinium sp. was isolated from anemones by manual homogenization method and then cultured and extracted. Brine shrimp lethality test was used for investigation of Symbiodinium sp. extracts toxicity. The effect of extracts on human pathogenic bacteria, Escherichia coli and Staphylococcus aureus was also investigated. Results showed that the cytotoxicity of Symbiodinium sp. extracts during 24 and 72 hours showed the highest cytotoxicity in Chabahar summer with less LC50 (0.179 and 0.075 mg/mL, respectively). Comparison of antibacterial properties showed that the highest zone of inhibition was related to winter in Qeshm Island, but it was less than the penicillin zone. In general, the study of methanolic extracts did not show antibacterial properties, while they showed lethal effects on A. salina. Therefore, Symbiodinium sp. can be used as more specific anti-cancer and anti-tumor tests as a cytotoxic dinoflagellate.