Investigation of antibacterial and antibiofilm effects of Cotinus coggygria Scop. and Rhus coriaria L. etyl acetate extracts

Nowadays, antibiotic resistance has emerged as a serious global threat. In particular, the treatment of bacterial infections associated with biofilm formation remains highly challenging. This challenge has highlighted the urgent need to explore novel antimicrobial agents from alternative sources. Among these, the extraction and therapeutic application of antimicrobial agents derived from medicinal plants have gained significant momentum. The aim of this study was to investigate the antibacterial and antibiofilm activities of Cotinus coggygria Scop. (Smoke tree) and Rhus coriaria L. (sumac ) plant extracts were evaluated against standard strains of S. aureus (MRSA), S. aureus (MSSA), E. faecalis, S. epidermidis, E. coli, K. pneumoniae, P. aeruginosa, A. baumannii, E. cloacae, and S. marcescens. Antibacterial activity was assessed using the broth microdilution method in accordance with CLSI guidelines, while antibiofilm activity was evaluated via the microtiter plate assay. For C. Coggygria Scop., the lowest MIC value (2.5 mg/mL) was observed against S. epidermidis, E. coli, A. baumannii, and S. marcescens. At the Minimum Bactericidal Concentration (MBC) level, only A. baumannii exhibited the lowest value of 2.5 mg/mL. In E. faecalis and A. baumannii strains, the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values were found to be equal. The highest biofilm inhibition was recorded in E. faecalis (47.39%), while the highest eradication rate was observed in P. aeruginosa (83.21%). For R. coriaria L., the lowest MIC value (0.62 mg/mL) was detected in MRSA and S. epidermidis strains. In MBC evaluations, S. epidermidis and A. baumannii showed the lowest values (1.25 mg/mL). The highest biofilm inhibition was observed in the MSSA strain (46.96%), while the highest eradication rate was recorded in E. faecalis (38.93%). In conclusion, C. coggygria Scop. and R. coriaria L. extracts exhibited varying levels of antibacterial and antibiofilm activities against clinically significant reference strains commonly associated with community-acquired and nosocomial infections.These plant extracts represent promising natural alternatives for the control of antibiotic-resistant pathogens and may contribute significantly to future therapeutic strategies.