Quorum Sensing Inhibition Activity of Water Extract of Rhizome Herbs on Aeromonas hydrophila

Several bacteria have been reported to be pathogenic to fishes, and some of them were opportunistic pathogen bacteria. Quorum sensing is a widespread phenomenon in bacteria on coordinating gene expression of virulence factors of bacterial pathogens, including biofilms. The aims of this research were to confirm biofilm formation by fish pathogenic bacteria, determine activity of water extracts of medicinal rhizome herb on growth and quorum sensing inhibition of Aeromonas hydrophila. Turmeric (Curcuma longa L.), temu lawak (Curcuma xanthoriza Roxb), ginger (Zingiber officinale Roscoe), kencur (Kaempferia galanga L.) and galangal (Alpinia galangal L.) rhizomes were used in this study. The extracts were examined on their activity to affect growth and inhibition of biofilms formation by A. hydrophila at concentrations of 40, 30, 20 and 10 mg/ml. Extract of rhizome medicinal herbs did not affect the growth of A. hydrophila. Ginger extract at concentration of 40 mg /ml showed the highest inhibition of biofilm formation by 79.7. Turmeric extract inhibited the biofilm formation by 59.9 at concentration of 30 mg / ml. Kencur extract showed the lowest biofilm inhibitory ability of 7.0. The results showed the addition of plant rhizome water extracts had anti-quorum sensing activity as evidenced by inhibition of the formation of these bacterial biofilms. © The Authors, published by EDP Sciences, 2020.