Chemical Composition Analysis and Antibacterial Mode of Action of Taxus Cuspidata Leaf Essential Oil against Foodborne Pathogens

Abstract

This study examined the antibacterial mode of action of Taxus cuspidata leaf essential oil (TCEO) against foodborne pathogenic bacteria. Gas chromatography–mass spectrometry analysis of microwave‐extracted TCEO resulted in examination of 34 different compounds, representing 81.63% of the total oil. The TCEO (1,000 μg per disc) showed antibacterial effect against Bacillus cereus ATCC 13061, Staphylococcus aureus ATCC 12600, Listeria monocytogenes ATCC 7644, Salmonella typhimurium ATCC 43174 and Escherichia coli ATCC 43889 as diameters of inhibition zones (22.0 ± 0.4 to 34.0 ± 1.2 mm). The minimum inhibitory concentration and minimum bactericidal concentration values of TCEO against the tested pathogens were found in the range of 250–1,000 μg/mL. Also, the TCEO had potential inhibitory effect on the viable counts of test pathogens. The TCEO revealed its mode of action on membrane integrity as confirmed by marked release of extracellular adenosine triphosphate, 260 nm absorbing materials and potassium ion efflux. The scanning electron microscopy analysis using TCEO further confirmed severe morphological alterations on the cell membrane of test pathogens. Practical Applications Because of frequent foodborne outbreaks and rising concern of consumers on the use of chemical preservatives in foods, the food industry is emphasizing the use of natural antibacterial agents from plant origin as safe food preservatives. Some selected plant materials are used as natural antimicrobials in food systems to prevent the growth of foodborne pathogens, resulting in the extension of shelf life of processed foods. Taxus cuspidata leaf essential oil (TCEO) is shown by this study to elicit its antibacterial action against foodborne pathogens through membrane permeabilization and can be used to control the growth of several foodborne pathogens. Hence, it is anticipated that TCEO may have greater potential for its practical application as an affective food preservative.

Growth Inhibitory Effects of Adhatoda vasica and Its Potential at Reducing Listeria monocytogenes in Chicken Meat

“…As ATP contributes significantly to a number of cell functions, including the transportation of essential ions and metabolites across the cell-membrane, the excessive loss of ATP through a disruption of the membrane permeability might be a positive indication of the loss of cell membrane integrity, thereby causing cell death, as reported previously (Herranz et al, 2001; Bajpai et al, 2014). …”

“…The release of essential ions or electrolytes from the bacterial cells after treatment with an antimicrobial could be considered a good indication of its antimicrobial effect (Bajpai et al, 2014). In the present study, when tested against L. monocytogenes NCIM 24563, AVELE induced the release of potassium compared to the control.…”

“…Furthermore, the release of these materials from bacterial cells is an indicator of a lack of membrane integrity (Bajpai et al, 2014). In the present UV-VIS study, the release of 260 nm-absorbing materials was proportional to the AVELE concentration, whereas the control cells showed no release of these materials after 120 min of exposure.…”

“…The disc diffusion method was used to assay the anti-listerial effects of AVELE (Bajpai et al, 2014 ). L. monocytogenes NCIM 24563 was grown in BHI broth and incubated at 37°C for 18–24 h. The bacterial growth of the culture was adjusted to ~10 7 CFU/mL, and an aliquot of the bacterial culture (100 μL) was spread over the plate count agar and dried on a clean bench for a few minutes.…”

“…A method devised by Bajpai et al ( 2014 ) was used to determine the amount of potassium ion leakage. The concentration of free potassium ions in the bacterial suspensions of L. monocytogenes NCIM 24563 was measured after exposing the bacterial cells to AVELE at 100 mg/mL in sterile peptone water for 0, 30, 60, 90, or 120 min.…”