Options
Screening of dietary phytochemicals for anti-quorum sensing properties
Author
Nur Aishah Abdul Rahim
Supervisor
Tan, Lik Tong
Abstract
Quorum sensing (QS) is a cell density dependent coordination of target genes expression in bacteria mediated by small, hormone-like compounds called autoinducers (AI) also known as acyl homoserine lactone (AHL). Numerous processes responsible for successful establishment of bacterial infection are QS-mediated. Therefore, inhibition of QS is considered as a fresh target for antimicrobial treatment at present. Dietary phytochemicals are secondary metabolites in plants known to have several health benefits including bactericidal activity. Nevertheless, their ability to inhibit QS has been only recently studied.
The aim of this investigation was to find out the effects of 20 bioactive dietary phytochemical extracts from common herbs and spices on modulating QS mediated by AI in model bioassay system. Modulation of QS, a process that is mediated by AHL, was carried out by disc diffusion assay tested at 2mg and 5mg of the phytochemical extracts, using the biosensor Chromobacterium violaceum 026 (CV026), a mini-Tn5 mutant strain of wild-type Chromobacterium violaceum that responds to exogenous C6- homoserine lactones thus producing the purple pigment violacein. Results from this investigation indicated that nine out of 20 phytochemical extracts tested inhibited quorum sensing by interfering with AHL activity.
The effect of 5mg of phytochemical extracts on swarming motility of the opportunistic pathogen Pseudomonas aeruginosa (PAO1) was also investigated. This was carried out on 0.7% LB agar plates point-inoculated with PAO1. It was found that 16 out of the 20 phytochemical extracts inhibited swarming in PAO1.
This study indicated that phytochemicals from foods can interfere with QSrelated processes. It unveils an exciting novel strategy for antimicrobial chemotherapy thus leading to the discovery of a new class of antibiotics, which can overcome the issues of antimicrobial resistance plaguing the medicine world today.
The aim of this investigation was to find out the effects of 20 bioactive dietary phytochemical extracts from common herbs and spices on modulating QS mediated by AI in model bioassay system. Modulation of QS, a process that is mediated by AHL, was carried out by disc diffusion assay tested at 2mg and 5mg of the phytochemical extracts, using the biosensor Chromobacterium violaceum 026 (CV026), a mini-Tn5 mutant strain of wild-type Chromobacterium violaceum that responds to exogenous C6- homoserine lactones thus producing the purple pigment violacein. Results from this investigation indicated that nine out of 20 phytochemical extracts tested inhibited quorum sensing by interfering with AHL activity.
The effect of 5mg of phytochemical extracts on swarming motility of the opportunistic pathogen Pseudomonas aeruginosa (PAO1) was also investigated. This was carried out on 0.7% LB agar plates point-inoculated with PAO1. It was found that 16 out of the 20 phytochemical extracts inhibited swarming in PAO1.
This study indicated that phytochemicals from foods can interfere with QSrelated processes. It unveils an exciting novel strategy for antimicrobial chemotherapy thus leading to the discovery of a new class of antibiotics, which can overcome the issues of antimicrobial resistance plaguing the medicine world today.
Date Issued
2009
Call Number
QR96.5 Nur
Date Submitted
2009