Screening methods for assessment of antibacterial activity in nature

There is a wide range of techniques to determine the antimicrobial activities in nature and natural products. The presence of different infectious diseases, the need to control them and also the enhancement in bacterial resistance have led researchers to for study for developing of new methods to determine the antimicrobial activities and the antimicrobials. The application of screening methods for identification of antimicrobial activities from natural sources is a navel issue with great importance. Even there is an ability to overcome the infection in nature such as some plants have shown resistance in specified organisms and this has led to researchers’ investigating their mechanisms of action and isolating active compounds. The dilution tests are used when the quantitative data are desired, the test is performed with anaerobic or microaerophilic microorganisms, the strains tested have impermanent growth rates and the effects of combinations of antimicrobials quantitatively are needed. This paper reviews the screening methods to determine antibacterial activity of natural products and shows some differences in these techniques.

Keywords:

antimicrobial activity , disk diffusion , broth dilution , agar cup.