Evaluation of Antibacterial Potential of Satureja montana L., Ocimum basilicum L. and Salvia officinalis L. Essential Oils against Reproductive Tract Pathogens in Cattle and their Toxicity Impact on Endometrial and Kidney Cells

Abstract

The abundant use of commercial anti-infective agents has led to the resistance development in bacterial strains, the presence of their residues in animal products and other negative consequences. The aim of the present work was to examine the antibacterial activity of EOs obtained from three plants (Satureja montana L., Ocimum basilicum L. and Salvia officinalis L.) against field isolates and reference bacterial strains of the most important pathogens in the cow endometrium. Their susceptibility was tested in vitro using a disk diffusion method, and the agar dilution test (ADT) and microdilution test (MDT) were used to determine the minimum inhibitory concentrations (MIC). In addition, the cytotoxic effect of the highest effective oil was tested by MTT, using the two cell lines, i.e. the BEND cell line (endometrium, 24h after exposure), and the MDBK cell line (kidney, 3, 6, 12 and 24h after exposure). The results of the antimicrobial assays suggest that the EO of S. montana, consisting mainly of p-cymene (42.8%) and carvacrol (28.1%), is a potent antimicrobial agent with high zones of inhibition determined on the disk diffusion method, where none of the individual isolates were resistant. Moreover, the calculated MIC values on both ADT and MDT were <1 mg/mL for bacterial isolates of all species. In addition, the oil exhibited low cytotoxic potential on both BEND (IC50=1.27 mg/mL) and MDBK cell lines (IC50=1.02-1.56 mg/mL). The obtained results indicate the possibility of the use of S. montana EO for the treatment of bacterial-induced reproductive diseases in cows.