A Review on Comparison of the Extraction Methods Used in Licorice Root: Their Principle, Strength and Limitation

Abstract

Medicinal plants are gaining much more interest and importance because of their use in treating many common diseases like cough, cold, fever and other ailments. One such natural herb scientifically called as “Glycyrrhiza glabra” and commonly known as “Licorice” is usually recommended for various health disorders. According to the literature, the main part of interest in the plant lies in its rhizomes (roots) which contain the active constituent Glycyrrhizic acid (Glycyrrhizin) a triterpenoid compound, that have been used for thousands of years as a superior expectorant forming a wonderfully effective ingredient in cough medicines and cough drops. Any kind of study on medicinal plants starts with their extraction procedures which plays a critical role to the extraction outcomes (yield and phytochemicals content) and also to the consequent assays performed. A wide range of technologies with different methods of extraction are available nowadays. Hence, this review aims to describe and compare the most commonly used extraction methods for Glycyrrhizin from Licorice roots, based on their principle, strength and limitation to help evaluating the suitability and economic feasibility of the methods. In addition, a novel postextraction method was formulated to avoid polymerization and contamination of the extracted glycyrrhizic acid which can be combined with the extraction methods to increase the therapeutic efficacy of the licorice root powder.