Amir Vazirizadeh

Different extracts of solitary marine tunicates have attracted attention as a source of amazing secondary metabolites with a wide range of promising potential biological effects. In the current study the antibacterial activity of the Persian Gulf marine tunicate “Phallusia nigra,” against the Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Pseudomonas aeruginosa, and Escherichia coli were investigated. The total flavonoid, phenolic, and alkaloid contents as well as, identification of their bioactive molecules were also analyzed. The tunicate extract showed significant antibacterial activities against the tested gram-negative bacteria strains. Chemical investigation of the methanol-chloroform extract by the GC-MS method, afforded the 23 compounds (C1–C23), with incredible and different structures. The extract had the highest amounts of flavonoid and phenolic contents. The result of flavonoids to phenolics ratio showed that the extract is rich in flavonoids. Amongst, 13 compounds including the C5, C9, C10, C12–C16, and C18–C22 belonged to different groups of flavonoids. From six nitrogenous organic compounds C1– C3, C7, C11, and C23 with a total abundance of about 36.74%, the bioactive heterocyclic compounds, C1, C7, and C23 have indole alkaloids, phthalazines, and thiadiazoles structures with potential known diverse pharmacological properties. At least, a portion of the antimicrobial and antioxidant activities may be due to the presence of these unique bioactive compounds in the extract. However, this marine organism can be subjected to different biological, phytochemical, and pharmacological and nutraceutical studies to find out the novel drugs.