Abstract

In the present investigation antimicrobial activity of solvent and aqueous extracts of Capparis decidua was determined against seven bacterial strains that isKlebsiella pneumoniae (ATCC 15380), Escherichia coli (ATCC 25922), Micrococcus luteus (ATCC 9341), Streptococcus pneumoniae (ATCC 12755), Staphylococcus aureus (ATCC 25923), Bacillus cereus (ATCC 11778) andLactobacilus acidophilus (ATCC 53103). From the experiments chloroform, acetone, methanol and ether extracts of Capparis decidua have shown very high susceptibility to the Lactobacilus that is MIC value was obtained in a range of 0.028 - 0.0625 μg/ml, while aqueous extracts have shown lowest MIC value in a case of Klebsiella pneumoniae and Micrococcus luteus. Similarly MBC values of various extracts were also determined in similar strains. Chloroform extract has shown lowest MBC value for Lactobacilus acidophilus i.e. 0.125 μg/ml followed by intermediate MBC values against Klebsiella pneumoniae and Escherichia coli(0.25 μg/ml). Further effectiveness of various plant extracts was determined in disc diffusion assays. The sizes of growth inhibition zone diameters were noted in presence of solvent and aqueous extracts. The strength of activity was presented as resistant; intermediate and susceptible. The highest growth inhibition zone diameter was obtained in methanolic extract that is 36 mm inBacillus cereus, 35 in Klebsiella pneumoniae, 36 in Escherichia coli and 31 inStaphylococcus aureus at 4 μg/disc. Pure compounds CS2, CS3, CS8 and CDF1 isolated from C. decidua have shown higher antimicrobial susceptibility in comparison to broad spectrum antibiotic that is tetracycline, ampicillin and ciprofloxacin. These have shown significantly very high inhibition zone diameters that is 22 - 40 mm at 4 μg/disc in agar disc diffusion assay.

Key words: Minimum inhibitory concentration, minimum bactericidal concentration, Capparis decidua.