Evaluation of Antimicrobial and Anti-Quorum Sensing Activity of Mazouj and Ghalghaf Galls Extracts of Oak against Pseudomonas aeruginosa

Background and Objectives: Infections caused by resistant Pseudomonas aeruginosa strains mostly originate from hospitals, and its prevalence is increasing in many countries of the world. Therefore, many efforts have been made to find new active plant compounds as an appropriate substitute for antibiotics. The purpose of this study was to evaluate the active compounds, antibacterial and antibiofilm activity of aqueous and methanol extracts of Mazuj and Ghalghaf galls against Pseudomonas aeruginosa. Methods: This study was performed on standard strain of Pseudomonas aeruginosa and a number of clinical strains. The methanol and aqueous extract of Mazuj and Ghalghaf galls, were prepared by Soxhlet method. Antibacterial activity of the extracts was assessed by well diffusion method, minimum inhibitory concentration (MIC) by microdilution method. The anti-quorum sensing activity of methanol and aqueous extracts of Mazuj and Ghalghaf galls was investigated on anti-biofilm activity of Pseudomonas aeruginosa. Results: The methanol and aqueous extracts of Mazuj and Ghalghaf galls showed antibacterial activity against Pseudomonas aeruginosa. The MIC values of the extracts were obtained to be 6.25 - 25 mg/ml. The extracts of Mazuj and Ghalghaf galls inhibited the formation of Pseudomonas aeruginosa biofilms in concentrations higher than 6.25. Conclusion: According to the results of this study, the extracts of Mazuj gall have appropriate antibacterial activity against the studied bacteria. Also, the methanol extract had higher antibacterial activity than the aqueous extract. Therefore, it is suggested that more extensive research be conducted on the identification of its antimicrobial compounds as a suitable alternative to antibiotics for the treatment of diseases