Crude Extract of Blue-Green Pigment Derived from the Marine Bacterium Pseudomonas aeruginosa P1.S9 has Antibacterial, Antioxidant, and Cytotoxic Activities

Pigment derived from marine bacteria is one of the alternative sources of natural products characterized by beneficial functions for pharmaceutical purposes. This study aimed to evaluate the antimicrobial, antioxidant and cytotoxic activities of the marine bacterium Pseudomonas aeruginosa P1. S9 crude pigment extract and identify its chemical content. Crude pigment extract of this bacterium showed promising antibacterial activities against Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli, and Staphylococcus aureus in a dose-dependent manner, as tested by the disc-diffusion method. This extract also exhibited 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) radical scavenging activity with an IC50 value of 164.05 µg/mL. Furthermore, this extract also had toxicity in shrimp larvae Artemia salina, with an LC50 value of 122.11 µg/mL, as evaluated by Brine Shrimp Lethality Test (BSLT). These results were supported by a cytotoxicity test against MCF-12A (human mammary epithelial cells) and MCF-7 (human breast adenocarcinoma cells) with an IC50 value of 265.47 and 171.98 µg/mL, respectively. GC-MS analysis identified that trans-2-decenoic acid was found as the most dominant compound in this extract.