Research Article: Biodiversity and screening of antimicrobial, antioxidant, and cytotoxic activity of bacteria isolated from the Persian Gulf sponge (Halicona oculata)

Screening of marine bacteria for developing new drugs is an emerging field in marine biotechnology. The purpose of this study was to investigate the diversity of sponge-associated bacteria from Kish and Larak islands (Persian Gulf) and to determine their antimicrobial, antioxidant, and cytotoxic activities. After sampling, bacteria were grown on the marine sponge agar medium. The isolated bacteria were characterized by polyphasic methods. The antimicrobial activity of the isolated bacteria was determined by the microdilution broth method. Cytotoxic activity was evaluated by MTT (۳-۴,۵-dimethylthiazol-۲yl-۲,۵-diphenyltetrazolium bromide) assay on human cell lines. Antioxidant activity was performed by inhibiting DPPH free radicals. Among ۱۲۱ bacterial isolates, Vibrio and Bacillus genera were the dominant frequency. The minimum inhibitory concentration of the extracted metabolites was recorded in the range of ۶۴ to ۵۱۲ µg/mL. The IC۵۰ of antioxidant activity varied from ۷۳.۴۲ to ۶۷۰.۹۰ µg/mL. The cytotoxic activity of the extracted metabolites ranged from ۴۰.۵۷ to ۱۸۱.۸۰ µg/mL against SW ۴۸۰ cell line and ۱۴۱.۳۰ to ۳۵۹.۷۰ µg/mL against HepG۲ cell line. The HL ۱۵, HL ۸۵, and HK ۵ extracts showed less toxicity against human umbilical vein endothelial cells. The results of genetic identification based on the comparison of ۱۶S rRNA gene sequence showed that the potent strains HL ۱۵, HL ۲۴, HL ۸۵, HK ۵, and HK ۳۶ belonged to B. safensis, V. alginolyticus, V. rotiferianus, B. aureus and Pseudomonas paralactis, respectively. The present study provided a new understanding of the diversity pattern and biological activity of the bacteria associated with Haliclona oculata.

کلیدواژه ها:

Antimicrobial activity ، Antioxidant activity ، Bacterial metabolites ، Cytotoxic activity ، Marine sponge ، Persian Gulf