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Antibacterial Mechanistic Effects of Flower Essential Oil of Ligustrum obtusifolium Through Altering Membrane Permeability Parameters

Bhalla, Piyush, Bajpai, Vivek K.
Journal of essential oil-bearing plants 2017 v.20 no.2 pp. 346-358
Bacillus subtilis, Escherichia coli O157, Ligustrum obtusifolium, Listeria monocytogenes, Salmonella enterica, Staphylococcus aureus, adenosine triphosphate, anti-infective agents, antibacterial properties, cations, chemical composition, essential oils, flowers, food pathogens, gas chromatography-mass spectrometry, membrane permeability, oils, plate count, potassium
An effort was made to investigate the chemical composition of hydrodistillated Ligustrum obtusifolium flower essential oil (LOFEO). Further, LOFEO was tested against various foodborne pathogens to confirm its antimicrobial effects. The GC-MS analysis confirmed the presence of 35 constituents in LOFEO, composing 84.91% of the oil. As expected, LOFEO exhibited considerable antimicrobial inhibitory effects (zone of inhibition: 12.6±0.1–18.2±1.0 mm) against Bacillus subtilis KCTC 3569, Staphylococcus aureus KCTC 1621, Listeria monocytogenes KCTC 3569, Salmonella enterica ATCC 4731 and Escherichia coli O157:H7 in agar assay with MIC and MBC of 250-500 and 250-1,000 μg/mL, respectively. LOFEO also inhibited cell viable counts and evoked its membrane disrupting effects against two selected foodborne pathogens B. subtilis KCTC 3569 and S. enterica ATCC 4731 as demonstrated by the increasing release of extracellular ATP (2.45 and 1.96 pg/mL), potassium ions (800 and 750 mmol/L), and relative electro conductivities (11.7 and 10.2%), as well as declining rates of 260-nm absorbing materials (3.8 and 3.7 OD), respectively. Overall findings reinforced the LOFEO to be an alternative means of natural antimicrobials.