Antibacterial and anti-biofilm activities of essential oils and their components including modes of action

Abstract

Nowadays, there is a wealth of information available related to the biological activities of essential oils and their components. The increase in the consumption of antibiotics in the past few years has been accompanied with a growth in bacterial antibiotic resistant; therefore, there is great interest in using essential oils. Here we summarized the information concerning the antibacterial activity of essential oils and their components. Essential oils have shown excellent antibacterial and antiadhesion activities against the microorganisms contained in biofilms and high potential anti-quorum sensing activity. Due to essential oils are mixtures of monoterpenes, sesquiterpenes and/or phenylpropanoids, the different functional groups and structural characteristics allow that the antibacterial activity of these compounds may be able to act on several bacterial targets. The essential oils compounds could delay the Lag phase, affect the cell membrane, its fatty acids composition, the enzyme and proteins, etc. The presence of the hydroxyl group is critical for antibacterial activity, but there are varying magnitudes of activity among different phenols. Although monoterpenes alcohols also have a hydroxyl group, they have a lower antibacterial activity than phenols attributed to the absence of an aromatic system. Thus, their topological or lipophilic characteristics seem to be the most important aspects in determining the antibacterial activity. Different aspects of the action of essential oils are discussed in this chapter, because there is great interest in using essential oils in the industrial to improve human health, particularly due to their antimicrobial properties.