Antibacterial activities of Dodonaea viscosa using contact bioautography technique

The crude ethanolic extract and n-hexane, dichloromethane, ethyl acetate, n-butanol and aqueous fractions of Dodonaea viscosa were analyzed for antibacterial potential against four Gram positive bacteria: Bacillus subtilis, Bacillus cereus, Micrococcus luteus, Staphylococcus aureus, and three Gram negative bacteria: Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa. Preliminary screening showed inhibition against Staphylococcus aureus, Micrococcus luteus, Escherichia coli and Pseudomonas aeruginosa. The thin layer chromatograms of the fractions were then subjected to contact bioautography, which showed inhibition zone at different R(f) values against Bacillus subtilis, Micrococcus luteus, Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa, indicating the presence of antibacterial components. The MIC of each fraction was determined through a 96-well micro-titer plate method. The non-viability of the organisms was ascertained by determining the MBC of the fractions.