Anti-Quorum Sensing Activity of Cymbopogon citratus onChromobacterium violaceum Isolated from the Water Environment

Abstract

Bacteria communicate via quorum-sensing (QS) before exhibiting any beneficial or
detrimental effect to man and the environment. This QS necessitates bacterial biofilm formation
leading to medical and environmental consequences. Interrupting QS using herbs may address
membrane biofouling, prevent biofilm-related diseases and reduce the chances of bacterial
resistance. In this study, leaves of Cymbopogoncitratus were extracted in n-hexane, acetone,
ethyl acetate, methanol and distilled water. Anti-quorum sensing (AQS) activities of the extracts
were investigated at qualitative and quantitative levels againstChromobacterium violaceum,
using solid and liquid media bioassays. Compounds with peak AQS activities were
characterized and identified using chromatographic techniques. The aqueous extract recorded
the highest yield (3.74%), which indicates the potential of distilled water to recover appreciable
quantity ofC. citratusextract. Widest zone of AQS activity (10.50mm) was obtained fromboth
aqueous and methanol extracts. Methanol extract revealed the peak violacein inhibition
(31.48%). This signifies that the polar extracts possessd compounds with better AQS features.
Gas chromatography–mass spectrometry (GC-MS) identified Hexadecanoic acid methyl
esteras the compoundwith the highest AQS activity.