Essential Oils as Green Antibacterial Modifiers of Polymeric Materials

The need for new strategies to reduce the susceptibility of polymeric materials to bacterial colonization is growing, especially with the emergence of drug-resistant bacterial strains. Antimicrobial agents used to modify polymers should not only be effective against microorganisms in both planktonic and biofilm states but also be safe and environmentally friendly. Phytochemicals, which are components of essential oils, may be a suitable choice to help combat microbial resistance to antibiotics. Furthermore, they meet the requirements of green chemistry. Essential oils synthesized by plants as secondary metabolites are capable of combating both Gram-positive and Gram-negative bacteria by disrupting lipid bilayers, affecting efflux pumps, compromising the integrity of bacterial cell membranes, and inhibiting the quorum-sensing system. They are also effective as adjuvants in antibiotic therapies. In this review, we outline the mechanism of action of various essential oil components that resulted in enhanced eradication of planktonic bacteria and biofilms. We summarize the use of these antimicrobial agents in macromolecular systems (nanovessels, fibers, nanocomposites, and blends) and provide an overview of the relationship between the chemical structure of phytochemicals and their antimicrobial activity, as well as their influence on the properties of polymeric systems, with a special focus on green active packaging materials.