In vitro antimicrobial activity of plant active components against Pseudomonas lundensis and Listeria monocytogenes

Abstract

This work aimed to study the antimicrobial activity of eight various components of plant origin on the growth of Pseudomonas lundensis and Listeria monocytogenes. Different in vitro methods were used: agar plate diffusion, micro atmosphere, agar hole diffusion, micro-dilution, and gradient-plate method. In the first agar plate assay, p-cymene and γ-terpinene did not inhibit the growth of the tested bacteria therefore they were not used in further experiments. Both α-pinene and limonene were only partially effective, but these were screened only for their partial inhibition. The other four components completely inhibited the growth of the tested bacteria. Using the agar-well diffusion method showed that carvacrol and thymol were found to be the most effective active components, thymol had minimum inhibitory concentration (MIC) at 1.563 mg/mL, however, in the case of carvacrol, MIC was 7.813 μL/mL. Additionally, eugenol and camphor show the same results but in higher concentrations. Gradient plate method was used to determine MIC values, in which it has been proved that carvacrol and thymol possess strong antimicrobial activity, no growth of tested bacteria was observed with carvacrol (100 μL/mL), while thymol exhibited MIC of 1.887 mg/mL against P. lundensis and 0.943 mg/mL needed to show complete inhibition of Listeria monocytogenes. Further experiments are needed to determine the optimum concentrations of the active components against P. lundensis and L. monocytogenes.

Potential Applications of Essential Oils for Environmental Sanitization and Antimicrobial Treatment of Intensive Livestock Infections

“…Cz, Ov EOs and mGR-OLI were all capable of significantly inhibiting the bacterial growth, with Cz EO turning out to be the strongest against S. Typhimurium strains, while Ov the best against E. coli strains. These results confirm the important role played by the EOs vapor phase that had already been highlighted in previous works [81][82][83][84], suggesting the possibility of nebulizing Cz, Ov EOs and mGR-OLI in animals' houses to reduce bacterial contamination as alternative prophylactic natural treatment able to sanitize the environment of intensive farming.…”

Elemental impact on antibacterial study of hydroalcoholic leaves extract of Belosynapsis vivipara

“…Antibacterial activity of the BV extract was assessed by the agar well diffusion method (Hussein et al, 2020) where each isolated microbe was subculture on the recommended specific media for each microorganism at 35-37 °C for 25 h. 100 mg of the BV extract were sterilized by filtration through a membrane filter. 6 mm discs were impregnated with sterile cock borer and 30 µl of BV extract was placed in the wells of agar plates inoculated with microbial culture (after dilution) including standard and then incubated all the plates 37 °C for 16 hours.…”