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

Abstract

Essential Oils (EOs) are mixtures of monoterpenes (MT), sesquiterpenes (ST) and/or phenylpropanoids (PhP) (Zygadlo 2011, Raut and Karuppayil 2014), with MT and ST being biosynthesized from mevalonate and/or deoxyxylulose (methyl D-erythritol 4-phosphate) pathways, while PhP come from a biosynthetic route of sikimic acid. The chemical diversity of EOs is high with aliphatic, cyclic and bicyclic structures, and is increased with the presence of different functional groups such as hydroxyls, carbonyls, carboxyls or esteres (Sell 2010, Zygadlo 2011). The great variety of bioactivities and the many mechanisms of action or targets are associated with the large molecular diversity of EOs (Koroch et al. 2007, Franz 2010, Sadgrove et al. 2015). In fact, several botanical families produce EOs, for examples Zingiberaceae, Rutaceae, Poaceae, Apiaceae, Asteraceae, Geraniaceae, Lamiaceae, Lauraceae, Myrtaceae, Pinaceae, Piperaceae, Verbenaceae and Santalaceae, with the EOs being biosynthesized and stored in special structures, such as glandular hairs or esquizogene channels (Franz 2010, Zygadlo 2011, Raut and Karuppayil 2014).