LAUSR

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 (24%) in the M. piperita L., carvacrol (85.88%) in the S. khuzistanica Jamzad, guaiazulene (25.6%) in the M. recutica L. carvacrol (51.12%) in the Z. multiflora Boiss and α-pinene (12.5%) in the R. officinalis L. Among plant extracts under study Z. multiflora had the lowest MIC (4.896 mg ml-1) and MBC (9.792 mg ml-1) and the maximum MIC and MBC were belonged to M. piperita (18.55 mg ml-1) and R. officinalis (33.645 mg ml-1) respectively. Also, the inhibition zone diameter of bacteria was determined by disc diffusion method and compared to erythromycin. The highest and the lowest Inhibition zone diameter were belonged to Z. multiflora (14.43±0.55 mm) and M. recutita (13.23±0.35 mm) respectively. Results showed that Z. multiflora extract exhibited highest antibacterial effect against S. iniae among all plant extracts in this study.