Abstract

      Background and Objectives: Antibiotic resistance in bacteria has actuated researchers toward evaluating many new antibacterial compounds of which are the thiazoles. In this research the inhibitory effects of novel thiazole derivatives were unraveled on Staphylococcus aureus, Streptococcus agalactiae, Pseudomonas aeruginosa and Klebsiella pneumoniae and oxothiazole liver toxicity effects were assessed on mice.

       Methods: The antibacterial effect of thiazole derivatives was evaluated by measuring the halo zone with disk diffusion method and dilution procedure in microplate in order to discriminate the minimum inhibitory concentration (MIC) and the liver toxicity of oxothiazole, also, was discerned by injecting 160 mg/kg, 265 mg/ kg and 350 mg/kg doses to mice as well as scrutinizing the liver histopathology.

      Results: Derivatives utilized in experiment had no inhibitory effect on Pseudomonas aeruginosa and Klebsiella pneumoniae, though their inhibitory effect was observed on Staphylococcus aureus and Streptococcus agalactiae. For Staphylococcus aureus and Streptococcus agalactiae the diameters of growth inhibition zone were 8.9-22.3 mm and 16.1-25.6 mm, respectively and MIC of 50-200 and 25-100 µg/ml by order. Additionally, by increasing the injection dose of oxothiazole with 160 mg/ml, 265 mg/ml and 350 mg/ml doses, the hepatitis lesions and liver necrosis were observed in experimental mice.

       Discussion: The thiazole derivatives possessed more inhibitory trace on gram positive bacteria than gram negative ones. Furthermore, the likely presence of oxygen link to thiazole ring in tested compounds results in the enhancement of inhibitory potency of these substances. Besides, our results suggest that high doses of oxothiazole cause severe liver damage and rapid death less than 24 hours.

       Keywords: Thiazole derivatives, Antibacterial effects, Oxothiazole, Liver toxicity.