Investigation of antibacterial properties of ethanolic extracts of four native medicinal plants of Ardebil province by two methods of disk and well diffusion

Resistance to antibiotic and also the side effects of drug consumption are the main problem in antibiotic treatment. Therefore, after doing researches on the plants properties, humankind has attempted to use them in different industries. In this investigation the anti-microbial effects of ethanolic extracts of four medicinal plants from Ardebil province include Nepeta nuda, Salvia verticilata, Nepeta crassifolia and Teocrium chamaedry subsp. syspirense, on three species of gram negative bacteria (Salmonella enteric, Escherichia coli, Pectobacterium carotovorum) were evaluated.
Material and An experimental study was conducted at in vitro conditions. After preparing ethanolic extract of mentioned plants by maceration method, the antimicrobial effect of outcome extracts from their aerial parts were investigated by two different disk diffusion and well diffusion.
The highest growth inhibition zone in E. coli¡ P. caratovorum¡ S. enterica bacteria at 800 mL/mg concentration in disk diffusion method (12, 12, 12 mm) at N. crassifolia, N. nuda, and N. crassifolia extracts and in well diffusion method (10, 12 and 11 mm) at S. verticilata, N. nuda and N. crassifolia extracts were seen respectively.
It seems that the different concentrations of extract and also bacterium type are influenced on growth inhibition zone. With increasing concentration, the inhibition zone is increased. In comparing to Gentamicin the extracts of mentioned plants had low effect on gram negative bacteria.