Characterization of the action of selected essential oil components on gram-negative bacteria

Ilkka Helander, Hanna-Leena Alakomi, Kyösti Latva-Kala, Tiina Mattila-Sandholm, Irene Pol, Eddy Smid, Leon Gorris, Atte von Wright

Research output: Contribution to journalArticleScientificpeer-review

1311 Citations (Scopus)


Carvacrol, (+)-carvone, thymol, and trans-cinnamaldehyde were tested for their inhibitory activity against Escherichia coli O157:H7 and Salmonella typhimurium. In addition, their toxicity to Photobacterium leiognathi was determined, utilizing a bioluminescence assay.
Their effects on the cell surface were investigated by measuring the uptake of 1-N-phenylnaphthylamine (NPN), by measuring their sensitization of bacterial suspensions toward detergents and lysozyme, and by analyzing material released from cells upon treatment by these agents.
Carvacrol, thymol, and trans-cinnamaldehyde inhibited E. coli and S. typhimurium at 1−3 mM, whereas (+)-carvone was less inhibitory. trans-Cinnamaldehyde was the most inhibitory component toward P. leiognathi. Carvacrol and thymol disintegrated the outer membrane and released outer membrane-associated material from the cells to the external medium; such release by (+)-carvone or trans-cinnamaldehyde was negligible.
Of the tested components, carvacrol and thymol decreased the intracellular ATP pool of E. coli and also inreased extracellular ATP, indicating disruptive action on the cytoplasmic membrane.
Original languageEnglish
Pages (from-to)3590-3595
JournalJournal of Agricultural and Food Chemistry
Issue number9
Publication statusPublished - 1998
MoE publication typeA1 Journal article-refereed


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