In vitro antimicrobial assay of selected medicinal plants against medically important plant and food-borne pathogens

The traditional use of plant materials for treatment of human ailments dates back to prehistoric times. In this study, the antipathogenic activity of 37 extracts of 23 plant species, which originally were used to control citrus pre-harvest diseases and human aliments are reported. An in vitro screening for antimicrobial activity was conducted against seven plant pathogens and five food-borne pathogens. In total, 21 extracts from 13 plant species exhibited some degree of antimicrobial activity to at least one pathogen. Of these, six species, i.e. Achyranthes aspera, Tribulus terrestris, Acacia seyal, Dolichos oliveri, Cissus quadrangularis and Mirabilis jalapa are species with no known previous reports of antimicrobial activity against the tested pathogens. The minimum inhibitory concentration (MIC) of eight selected plant extracts were found to be between 1:2 and 1:5 (v: v). none of the extracts inhibited Escherichia coli or Erwinia carotovora. On the other hand, three plant extracts inhibited a bacterial strain with complete resistance to all antibiotics tested. Further elucidation of the active ingredients of these plant extracts is commendable for practical utility and control of resistance development