Antibacterial Activity of Otostegia limbata

The aim of this work was to examine the antimicrobial effect of Otostegia limbata extracts obtained with solvent of different polarities on six different bacteria. Powdered aerial parts of the O. limbata plant were extracted with ethanol and then dry later made solution in threev solutions, dimethylsulphoxide (DMSO) and methanol.. Antimicrobial activities of three extracts were tested on 6 bacterial strains using Disk Diffusion Method (DDM), Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). The results values showed that Staphylococcus aureus was most sensitive against all three extracts. The highest zone of inhibition (ZOI) value of S. aureus against DMSO extract was 19 +/- 1.5. No antimicrobial activity was observed against the Pseudomonas aeruginosa, while only ethanolic extract showed some antimicrobial activity against Escherichia coli with ZOI value of 11.5 +/- 1.1 and the extracts inhibited the growth of the bacterial isolates in a concentration dependent manner with MICs ranging from 0.5-2 mg mL(-1). This is the first report of the antibacterial potency of O. limbata. The findings provide the evidence that O. limbata as a good medicinal plant for further investigations.