Isolation and Antibacterial Activity of Indole Alkaloids from Pseudomonas aeruginosa UWI-1

• Published in: Molecules (Basel, Switzerland) Switzerland), 2020-08, Vol.25 (16), p.3744
• Main Authors: Ramkissoon, Antonio, Seepersaud, Mohindra, Maxwell, Anderson, Jayaraman, Jayaraj, Ramsubhag, Adesh
• Format: Article
• Language: English
• Subjects: Alkaloids; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - isolation & purification; Anti-Bacterial Agents - pharmacology; Antibacterial activity; antibacterial compounds; Antibiotics; Antimicrobial activity; Antimicrobial agents; Bacteria; Bacteria - drug effects; Bacteria - growth & development; Bioactive compounds; Bioassays; Biosynthesis; bis(indol-3-yl) phenylmethane; Carbon; Chemical compounds; Fermented food; Fractionation; Genes; Genomes; Gram-negative bacteria; Gram-positive bacteria; Humans; Hydrocarbons; indole alkaloids; Indole Alkaloids - chemistry; Indole Alkaloids - isolation & purification; Indole Alkaloids - pharmacology; Indoles; Indoles - chemistry; Indoles - isolation & purification; Indoles - pharmacology; Mass spectrometry; Mass spectroscopy; Metabolism; Metabolites; Microbial Sensitivity Tests; Microorganisms; Minimum inhibitory concentration; natural products; NMR; Nuclear magnetic resonance; Pathogens; Pseudomonas aeruginosa; Pseudomonas aeruginosa - chemistry; Quinazolines - chemistry; Quinazolines - isolation & purification; Quinazolines - pharmacology; tris(1H-indol-3-yl) methylium
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules25163744

In this study, we report the first isolation of three antibiotic indole alkaloid compounds from a Pseudomonad bacterium, UWI-1. The bacterium was batch fermented in a modified Luria Broth medium and compounds were solvent extracted and isolated by bioassay-guided fractionation. The three compounds were identified as ( ) tris(1H-indol-3-yl) methylium, ( ) bis(indol-3-yl) phenylmethane, and ( ) indolo (2, 1b) quinazoline-6, 12 dione. A combination of 1D and 2D NMR, high-resolution mass spectrometry data and comparison from related data from the literature was used to determine the chemical structures of the compounds. Compounds were evaluated in vitro for their antimicrobial activities against a wide range of microorganisms using the broth microdilution technique. Compounds and displayed antibacterial activity against only Gram-positive pathogens, although had significantly lower minimum inhibitory concentration (MIC) values than . Compound displayed potent broad-spectrum antimicrobial activity against a range of Gram positive and negative bacteria. Several genes identified from the genome of UWI-1 were postulated to contribute to the biosynthesis of these compounds and we attempted to outline a possible route for bacterial synthesis. This study demonstrated the extended metabolic capability of in synthesizing new chemotypes of bioactive compounds.