Plant Sampling for Production of Essential Oil and Evaluation of Its Antimicrobial Activity In Vitro

Essential oils (EOs) and oleoresins are complex mixtures mainly made up of terpenes, synthesized by a wide variety of plants. Individual terpenes may show broad-spectrum activity against different plant pathogens, and their combination into EO and oleoresin mixtures enhances plant chemical defense. The interest in EOs has significantly increased due to the trend of using natural products as herbicides, insecticidal and antimicrobial agents. In addition, the use of plant mixtures is an emerging approach to face the problem of antimicrobial resistance in agriculture. This chapter reports guidelines about plant sample collection for the production of EOs and provides protocols to test their activity as antimicrobial agents against bacteria and fungi. It also describes a solvent-free method for the inclusion of EOs into β-cyclodextrins. This type of formulate is prepared to turn liquid EOs into easily manageable water-soluble powders, and to control the release of volatile compounds, aiming to increase EOs' applications in agriculture.