Antioxidant, Anti-quorum Sensing and Cytotoxic Properties of the Endophytic Pseudomonas aeruginosa CP043328.1 's Extract

Background: Novel bioactive compounds are in high demand to combat challenges of microbial resistance. In recent years, secondary metabolites from endophytic bacteria have drawn attention from researchers due to their novel structures and significant biological activities. Objective: This study aimed at extracting secondary metabolites from endophytic Pseudomonas aeruginosa CP043328.1 from Anredera cordifolia leaves for their biological activities. Methods: The anti-SMASH was used to predict the biosynthetic gene clusters of P. aeruginosa CP043328.1. The bacteria was resuscitated on Nutrient agar. Ethyl acetate was used to extract the secondary metabolites. Chemical composition of the secondary metabolites was evaluated using gas chromatography-mass spectrometry (GC-MS) and 2, 2-diphenyl-1-picrylhydrazyl (DPPH), and 2, 2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) methods were used to analyze the scavenging activity. Anti-quorum sensing activity was investigated using Chromobacterium violacuem ATCC 12472 as the biological indicator. Cytotoxicity assay was performed using a tetrozolium-based columetric (MTT) assay. Results: The bacterium has 12 gene clusters that encode for secondary metabolites. The extract revealed 15 volatile constituents with diisooctyl phthalate (50.51%) and [1, 2, 4] oxadiazole, 5-benzyl-3 (10.44%) being the major compounds. The extract revealed scavenging capabilities with IC₅₀ of 0.625 mg/ml for DPPH and 0.15 mg/ml for ABTS. It displayed anti-quorum sensing activity with 88% violacein inhibition at 3.31 mg/ml. According to MTT assay, the extract was found to be safe for use up to 2000 μg/mL. Conclusion: P. aeruginosa CP043328.1 shows a potential use as a source of pharmacologically important metabolites.