Plants produce secondary metabolites for defense and based on the biosynthetic pathway, these chemical compounds are broadly divided into three categories namely nitrogen-containing compounds, phenolic compounds, and terpenes. Essential oils and other such compounds are known for their biological activities. The extraction of essential oils is a challenging aspect for researchers in the field of natural products. Hydrodistillation is a time-consuming and very tedious method. Nowadays, accelerated solvent extraction, supercritical fluid extraction, subcritical water extraction, microwave hydrodiffusion are promising alternatives for conventional methods with several advantages. Essential oils have several biological activities in the field of pharmacological, ethnopharmacological, pesticidal, etc.
Part of the book: Essential Oils