Screening of Antibacterial Activity of Six Plant Essential Oils Against Pathogenic Bacterial Strains

In the present investigation antimicrobial activity of six different plant essential oils i.e., citrus (Citrus lemon), olive (Olea europaea), ajwain (Trachiyspirum ammi), almond (Amygdalus communis), Bavchi (Psoralea corylifolia) and neem (Azadirachta indica) oils have been evaluated. After bioassays, most of the essential oils were found susceptible to both Gram-positive bacteria such as Lactobacillus acidophilus, Streptococcus pneumoniae, Staphylococcus aureus, Micrococcus luteus, Bacillus cereus and Gram-negative bacteria Klebsiella pneumoniae, Escherichia coli. For screening of antimicrobial susceptibility in each essential oil, both positive and negative controls were set to determine MIC (minimum inhibitory concentration), MBC values (minimum bactericidal concentration) and growth inhibition zone diameters. Among all essential oils almond and neem oils were found to be highly bactericidal, as it has shown lowest MIC and MBC values and high growth inhibition zone diameter in comparison to antibiotics. Present study reveals significantly higher broad-spectrum antibacterial activity in essential oils than antibiotics i.e., tetracycline, ampicillin and ciprofloxacin.