Effect of Solvent Polarity on Extraction Yield of Total Flavonoids with Special Emphasis to Glabridin from Glycyrrhiza glabra Roots

Some of the solvents used for glabridin extraction include ethanol (Tian, 2008), acetone (Ao, 2010), ethyl acetate (EA) (Xu, 2009), supercritical fluid CO2 (Cho, 2004), methanol (Bhan, 2017) and imidazolium-based ionic liquids (Li, 2012). [...]since glabridin is sensitive to temperature (Ao, 2010), the high energy consumption due to sample extraction time and high extraction temperature affects the final yield of the product. Since the licorice extracts are used in the cosmetic and food industries, having these extracts without residues of toxic solvents would be beneficial. The requirement of pure glabridin as a chemical reference standard for quality control studies and identification of Glycyrrhiza glabra roots and for biological/pharmacological investigations (Vishwanathan, 2019), tempted us to reinvestigate the method of extraction of glabridin from licorice so that the processes are cost-effective and reproducible without impacting their quality. The present study was designed to study the impact of different extraction solvents and its moisture content on the yield of glabridin and total flavonoids (TF) from Glycyrrhiza glabra roots, with particular emphasis also on effects of recovered solvents on the extraction efficiency of TF and glabridin, under similar extraction conditions.