Determination of antimicrobial and anti-quorum sensing activities of water and ethanol extracts of propolis

Abstract

Quorum Sensing is a special system between bacteria to communicate with the signal molecules. Propolis is a resin collected from plants by honey bees. The present study examined anti-quorum sensing and antimicrobial activities of water and ethanol extracts of propolis. The antimicrobial activities of the propolis extracts were studied against Escherichia coli ATCC 25922 Gram (-), Listeria monocytogenes ATCC 7644, Streptococcus mutans CNCTC 8/77, Staphylococcus aureus ATCC 25923 Gram (+), Candida albicans ATCC 10239 (yeast) by the well diffusion method. Anti-quorum sensing activity, violacein inhibition activity, and anti-swarming activity were studied using Chromobacterium violaceum CV026 and C. violaceum ATCC 112472, and Pseudomonas aeruginosa (PA01) respectively. Both propolis extracts were detected antibacterial activity against Gram (+) bacteria and Candida albicans. However, antibacterial activity against Gram (-) bacteria were not observed. While the antimicrobial activity of water extract propolis was determined more effectively than ethanol extract, anti-quorum sensing and anti-swarming activities less effective. It was also detected that both extracts display violacein inhibition. It was revealed that the antimicrobial, anti-quorum sensing, anti-swarming activity depended on the dose of propolis extracts. Thirty-six phenolic compounds were analysed of propolis extract by HPLC-DAD. The amount and presence of phenolic compounds in the ethanol extract were more than the water extract apart from benzoic acid, cinnamic acid, syringic acid, (±) epigallocatechin, vitexin, rutin, and trans-chalcone. Consequently, the study put forward that the phenolic compounds of propolis have antibacterial, anti-quorum sensing, violacein inhibition, and anti-swarming activities changing depend on directly the extraction solvent and phenolic compounds.