Essential oils are aromatic, volatile liquids obtained from plant material through steam distillation and named after the plant from which they are derived.
Essential oils can be defined as either products or mixtures of fragrant substances or as mixtures of fragrant and odorless substances.
These fragrant substances are chemically pure compounds that are volatile under normal conditions. Essential oils vary greatly, sometimes due to genetic causes, but also because of climate, rainfall, or geographic origin.
They are composed principally of lipophilic and highly volatile secondary plant metabolites, principally mono- and sesquiterpenes, but other types of compounds such as allyl and isoallyl phenols may also be present.
Other substances that have been identified in volatile oils include coumarins, anthraquinones, and alkaloids, which are often distillable, while some diterpenes, fat, and other nonvolatile compounds can be obtained from essential oils by methods other than distillation.
The applications of essential oils are diverse. Widely used in cosmetics and perfumes, they also have medicinal applications due to their therapeutic properties as well as agro-alimentary uses because of their antimicrobial and antioxidant effects.