Antibacterial activities of the ultrasound assisted extracts of Laurus nobilis, Peganum harmala and rosemary

The present study was aimed to investigate the antibacterial activities of the Laurus nobilis,Peganumharmala and rosemary extracts against Staphylococcus aureus and Escherichia coli. Thus, the ultrasonic extracts were performed using the aqueous, ethanol, hydro-alcoholic or chloroform phases. The microdilution technique was used to evaluate the antibacterial activities which was finally reported as the MIC and MBC values. All the extracts showed the antibacterial activities against the bacteria at the concentration of 6.25%. However, the metalonic extract exert a maximum antibacterial activity. The extract of three plants revealed the same antibacterial activity against E. coli, but the ethanoloic extract from P. harmala showed a maximum antibacterial activity against S. aureus at the concentration of 6.25%. Results of the current study showed the similar antibacterial activities of the extracts against E. coli; meanwhile, the maximum antibacterial effect on S. aureus was observed by applying alcohol or water as a solvent. In general, this paper proposed that ultrasound assisted extraction was quick and cost effective approach to extract the plants. In addition, ethanolic solvent was found as the best selection among the aqueous, hydro-alcoholic or chloroform solvents.