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

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 mu M) and minimal bactericidal (MBC: 50 mu M) concentrations. Moreover, no viable cells were detected within 16 h of incubation at 50 mu M. 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-beta-cyclodextrin/nerolidol inclusion complex showed MIC and MBC values of 100 and 200 mu M, 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.