Techniques for extraction, isolation, and standardization of bio-active compounds from medicinal plants

Abstract

Naturally occurring plant-based compounds have been used by generations of practicing physicians of indigenous systems of medicine, since hundreds years. Currently, these are in much demand due to their efficacy, safety, and minimal side effects. Extraction of plant materials can be done by various conventional and non-conventional extraction procedures including maceration, infusion, percolation, digestion, decoction, Soxhlet extraction, ultrasound-assisted extraction, turboextraction, countercurrent extraction, microwave-assisted extraction, ultrasound extraction, supercritical fluid extraction, solid-phase extraction, and column chromatography. Recent techniques of extraction include ionic liquid extraction, high performance liquid chromatography, gas-phase chromatography, chiral phase chromatography, etc. The plant extracts obtained are ready for use as a medicinal agent in the form of dried powder or fluid extracts, and these may be further processed to be incorporated in dosage forms, such as tablets or capsules, or it may be fractionated to isolate individual chemical entities which are then marketed in the form of modern drugs. Thus, the aim of this chapter is to provide an overview on the different extraction techniques used for the isolation of bio-active constituents from medicinal plants, and also to provide a detailed account on the various phytodrugs.