Effect of Bromination on the Quorum Sensing-Inhibiting Properties of Indole-3-Carboxaldehydes in <i>Chromobacterium violaceum</i> AHL System

• Main Authors: Chesley A. Kemp, Donna K. McCullough, Dobrusia Bialonska, Paul J. T. Johnson
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: Microbiology Research
• Subjects: quorum sensing; bromination; quorum sensing inhibition; indole; carboxaldehyde; <i>Chromobacterium violaceum</i>
• Online Access: https://www.mdpi.com/2036-7481/12/2/25

Quorum sensing (QS) is a form of bacterial communication involved in the production of virulence factors in many species. As a result, inhibition of quorum sensing may be of use in mitigating pathogenesis. The signaling molecule indole is currently being investigated as a target for quorum sensing inhibition (QSI) and the indole derivative indole-3-carboxaldehyde (ICA) has been shown to inhibit quorum sensing-mediated behaviors in <i>Escherichia coli</i>. In this study, we investigate bromination as a method of increasing the QSI capabilities of indole carboxaldehydes. The IC₅₀ values of three monobrominated indole carboxaldehydes (5-bromoindole-3-carboxaldehyde, 6-bromoindole-3-carboxaldehyde, and 7-bromoindole-3-carboxaldehyde) were determined and compared to the IC₅₀ value of ICA. The bromination of these indole carboxaldehydes reduced the IC₅₀ values between 2- and 13-fold, indicating that bromination significantly increases the potency of these indole carboxaldehydes.