In vitro antibacterial activity of crude leaf extracts of Mangifera indica Linn

Abstract

The active components of leaves of Mangifera indica L. were extracted using cold water and organic solvents (acetone and methanol) and were tested againstStaphylococcus aureus, Streptococcus pyogenase, Streptococcus pneumoniae, Bacillus cereus, Escherichia coli, Pseudomonas aerugenosa, Proteus mirabilis, Salmonella typhi and Shigella flexnerri using the agar well (cup plate) diffusion method. Both the acetone and methanol extracts inhibited the growth of gram positive bacteria, with acetone extract exerting more activities on all the gram positive bacteria with zone of inhibition between 15 - 16 mm, and a gram negative bacterium S. typhi (14 mm) at 250 mg/ml. Whereas, water extract was not active on any of the bacterial pathogens tested at any of the concentration of the extract used. The activities of the plant extracts on the inhibited pathogens using the zone of inhibition were not as effective as the standard commercial antibacterial disks of gentamicin and erythromycin (t = 2.23, p < 0.05). Increased temperature (60 and 100°C for 1 h) had a multiplier effect on the activity of the extracts, but alkaline pH decreased the activity. Preliminary phytochemical analysis revealed the presence of tannins, glycosides, saponins and phenols. The MIC and MBC of the extracts was in the range of 12.5 - 75 and 25 - 175 mg/ml respectively. There is a basis for the traditional use of the plant as a local health remedy. Key words: Antibacterial activity, MIC, MBC, gram-positive bacteria, gram-negative bacteria, Mangifera indica, extract.