Selection of nerolidol among a series of terpenic and phenolic compounds for its potent activity against Lactobacillus fermentum ATCC 9338

Abstract

Essential oil components are widely used for their antibacterial activity against spoilage microorganisms in food. Lactobacillus fermentum is a Gram-positive lactic acid bacteria responsible for the deterioration of various food products, including beverages and dairy products. In this study, 17 terpenic and 11 phenolic compounds were screened against the food spoilage microorganism Lactobacillus fermentum ATCC 9338. The antibacterial activity of the tested compounds was dependent on hydrophobicity and particular chemical features. Nerolidol solubilized in dimethylsulfoxide exhibited the highest antibacterial activity and showed low minimal inhibitory (MIC: 25 μM) and minimal bactericidal (MBC: 50 μM) concentrations. Moreover, no viable cells were detected within 16 h of incubation at 50 μM. The important antibacterial activity of nerolidol against L. fermentum is probably related to the high hydrophobicity, the aliphatic chain length, and the presence of the hydroxyl group. Hydroxypropyl-β-cyclodextrin/nerolidol inclusion complex showed MIC and MBC values of 100 and 200 μM, respectively. The total bacterial kill was observed after 12 h of incubation. The results obtained with the inclusion complex are probably due to the time required to allow nerolidol to be released from the inclusion complex.

Mandarin essential oil as an antimicrobial in ethanolic fermentation: Effects on Limosilactobacillus fermentum and Saccharomyces cerevisiae

“…Ephrem et al . (2019) evaluated the antimicrobial activity of 17 terpenic and 11 phenolic compounds against the same strain of L. fermentum (ATCC ® 9338™). The authors reported nerolidol as the most effective compound as it achieved a complete loss of cell culturability after 16 h of incubation at the concentration of 50 µM.…”

“…Linalool, on the other hand, when used at the concentration of 3500 µM, exhibited both cell growth inhibition and bactericidal effects (Ephrem et al . 2019). In terms of % (v/v) unit, the concentration of 0·06% (3500 µM) of both limonene and linalool was bactericidal.…”

“…However, when the results obtained for limonene and linalool (the most expressed compound in terms of quantity in the mandarin EO) in the above-stated study were analysed, it was observed that the limonene, when used at a concentration of 500 µM, resulted in the complete loss of bacterial growth, while at the concentration of 3500 µM, it exhibited a strong bactericidal activity. Linalool, on the other hand, when used at the concentration of 3500 µM, exhibited both cell growth inhibition and bactericidal effects (Ephrem et al 2019). In terms of % (v/v) unit, the concentration of 0Á06% (3500 µM) of both limonene and linalool was bactericidal.…”

Perspectives on the microorganism of extreme environments and their applications

“…Biosurfactants combat adhesion and colonization of pathogenic microbes with their antiadhesive and antibiofilm abilities e.g. surgical implants treated with biosurfactants obtained from Lactobacillus fermentum, a thermo-acidophilic lactic acid bacteria were found to inhibit the infection of Staphylococcus aureus, PVC plates and vinyl urethral catheters treated with surfactin showed reduced biofilm formation of E.coli ( Ephrem et al., 2019 ; Markande et al., 2021 ; Shekhar et al., 2015 ). They can potentially be used in gene transfection (specifically liposome-based biosurfactants) and can act as alternatives for gene delivery mechanisms and immunological adjuvants because of their low toxicity and pyrogenicity ( Shekhar et al., 2015 ).…”