Phytochemical screening and In vitro antibacterial activity of three selected plant extracts against some phytopathogenic bacteria

In vitro study of antibacterial activity and minimum inhibitory concentrations of whole plant extract of Croton hirtus L Her., Boerhaavia diffusa Linn. and Eclipta alba Hassk. were investigated against four important phytopathogenic bacteria which are causing diseases in vegetable crops. Antibacterial activity test was performed by Agar well diffusion method and minimum inhibitory concentration by Borth dilution assay. Five different extractions of methanol, ethanol, acetone, chloroform and water were prepared for each plant species and screened for various phytoconstituents and antibacterial activities. Phytopathogenic bacteria selected include Xanthomonas oryzae, Xanthomonas campestris, Erwinia carotovora and Ralstonia solanacearum. PrelirT\inary phytochemical screening was conducted to identify the class of compounds present in different extracts. The study revealed that methanol extracts of E. alba demonstrated a better antibacterial activity against X. oryzae, X. campestris and E. carotovora whereas the best activity against R. solanacearum was exhibited by acetone extracts of B. diffusa. The inference in the study indicates these extracts of plants may contain better and higher concentration of specific active components compared to other selected extracts.