Inhibition of quorum sensing by partially purified anti-quorum sensing compound from the marine epibiotic bacteria in Chromobacterium violaceum

Quorum sensing system majorly contributes in the virulence of many microorganisms. Attenuation in the quorum sensing system by interaction with the signalling molecules can be an effective approach to reduce the use of anti-microbial agents. The aim of the study is to investigate quorum sensing inhibitory activity of microbes from the marine source. A total of 60 epibiotic bacteria were isolated: 4 isolates were anti-QS producer and one of them with potent anti-QS activity was identified as Pseudomonas stutzeri SJ4. The ethyl acetate extract of P. stutzeri SJ4 inhibited violacein pigment of Chromobacterium violaceum by 72.83%. To characterise the active compound, TLC and GC-MS were performed. GC-MS showed major 5 peaks whose compounds were docked with the Quorum sensing receptor CviR of C.violaceum. Molecular docking results indicated that 2,6,10,14- tetramethyl hexadecane showed highest binding energy -8.0 kcal/mol which is quite higher than control compound N-Decanoyl-DL-homoserine lactone, exhibiting -7.5 kcal/mol.