Extraction Techniques for Medicinal and Aromatic Plants

Medicinal and aromatic plants are potential sources of bioactive molecules with a broad spectrum of therapeutic uses. There are many methods to extract and purify these compounds. Solvent extraction, steam distillation, Soxhlet extraction, percolation, maceration, etc. are commonly employed traditional methods of extraction of medicinal and aromatic plants a large scale. However, these approaches also have some drawbacks, including the lengthy extraction time, high solvent usage, and risk of degradation of bioactive compounds. There are also a number of new extraction methods that have been developed in recent years and are generally acknowledged for higher efficiency, selectivity, and sustainability. Some of these are microwave-assisted extraction, ultrasound-assisted extraction, supercritical fluid extraction, and pressurized liquid extraction. The extraction procedures have their own advantages and disadvantages, and the choice of method depends on the plant material, the composition of the desired compounds in the extracts, and the extract quality. Optimization of extraction parameters is considered necessary for obtaining not only high yields but also the integrity of the bioactive compounds. Hence, it is imperative to adopt an efficient and eco-friendly method to obtain an extraction of quality from medicinal and aromatic plants. Efficient and sustainable extraction methods are needed to obtain top-quality extracts of medicinal and aromatic plants. This chapter reviews the principles of extraction methods, the merits and demerits of these methods, and the features that are necessary for selecting suitable extraction methods for a particular application.