A.A. Tafi - Department of Fisheries, Faculty of Natural Resources, Urmia University
S. Meshkini - Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Urmia University
A. Tukmechi - Department of Microbiology, Faculty of Veterinary Medicine, Urmia University
M. Alishahi - Department of Clinical Science, Faculty of Veterinary Medicine, Shahid Chamran University
F. Noori - Department of Aquaculture, Artemia & Aquaculture Research Institute

Streptococcosis is an infectious disease with significant economic and sanitary repercussions for trout farms in the world. The objective of this study was characterize the chemical constituents and  in vitro antibacterial properties of Mentha piperita L., Satureja khuzistanica Jamzad, Matricaria recutica L., Zataria multiflora Boiss and Rosmarinus officinalis L. extracts against streptococcus iniae. The chemical components of the selected hydroalcoholic extracts were also analyzed by GC/MS. The most constituents were menthol (۲۴%) in the M. piperita L., carvacrol (۸۵.۸۸%) in the S. khuzistanica Jamzad, guaiazulene (۲۵.۶%) in the M. recutica L. carvacrol (۵۱.۱۲%) in the Z. multiflora Boiss and α-pinene (۱۲.۵%) in the R. officinalis L. Among plant extracts under study Z. multiflora had the lowest MIC (۴.۸۹۶ mg ml-۱) and MBC (۹.۷۹۲ mg ml-۱) and the maximum MIC and MBC were belonged to M. piperita (۱۸.۵۵ mg ml-۱) and R. officinalis (۳۳.۶۴۵ mg ml-۱) respectively. Also, the inhibition zone diameter of bacteria had determined by disc diffusion method and compared to erythromycin. The highest and the lowest Inhibition zone diameter were belonged to Z. multiflora (۱۴.۴۳±۰.۵۵ mm) and M. recutita (۱۳.۲۳±۰.۳۵ mm) respectively. Results showed that Z. multiflora extract exhibited highest antibacterial effect against S. iniae among all plant extracts in this study.

Herbal extracts, Antistreptococcal property, Minimum inhibitory concentration, Minimum bactericidal concentration