Exploring the Antibacterial Potential of Nepeta crispa Essential Oil Against Agro-Food Bacteria

Herbal essential oils are considered suitable candidates for controlling plant diseases due to their safety for humans and the environment, as well as their economic benefits. This study investigates the antibacterial activity of the essential oil of a native plant of Iran, Nepeta crispa Willd. After extraction of the essential oil by hydrodistillation, the antibacterial effect was examined using the disk diffusion method on solid media and MIC and MBC determination by microdilution in liquid media against harmful Gram-negative and Gram-positive bacteria. The essential oil of N. crispa exhibited strong inhibitory activity in both solid and liquid media against various bacteria, including plant and foodborne pathogens. The highest inhibitory effect on solid media was observed against Xanthomonas euvesicatoria pv. perforans and Rathayibacter sp., while the weakest antibacterial activity was observed on E. coli and Mycetocola sp. In liquid media, the lowest MIC and MBC values (indicating highest sensitivity) were recorded for Clavibacter tessellarius and Curtobacterium flaccumfaciens , whereas Salmonella typhi showed the greatest resistance. Overall, this essential oil exhibited significant antibacterial activity, particularly against Gram-positive plant bacteria. A total of 94 compounds were identified in the oil, with Eucalyptol (10.93%), Nepetalactone (9.58%), and p-menth-1-en-8-ol (8.4%) being the dominant components. These findings demonstrate the broad antibacterial potential of N. crispa for the first time. Based on the achieved results, the essential oil of N. crispa could be used as a natural antibacterial agent against different bacteria, which would provide opportunities for further applications in the food and agricultural sector.