Antimicrobial activity of several Brazilian medicinal plants against phytopathogenic bacteria

What is currently raised as a new approach in the management of plant diseases is the development and formulation of plant based biopesticides. The objective of present study is to evaluate the antibacterial activity of aqueous extracts of twelve species belonging to seven families collected from the Northeast of Brazil against four economically important phytopathogenic bacteria. Antibacterial activities of the aqueous extracts were studied by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Twelve aqueous extracts of twelve species were evaluated. Only three extracts were not active against Ralstonia solanacearum and other three extracts were not active against Xanthomonas campestris pv. campestris. Anadenanthera colubrina var. cebil, Croton pedicellatus and Eugenia brejoensis presented a broad spectrum of the inhibitory effect (MIC 3.12 to 12.5 mg/mL). According to these results, we conclude that the flora in the northeast of Brazil can be regarded as a rich source of plants with antibacterial activity. Therefore, further screening of other plant species, identifying active fractions or metabolites and in vivo application of active extracts are warranted. Key words: Caatinga, Atlantic Forest, antibacterial activity, aqueous extract, anti-phytopathogenic activity.