The root of Glycyrrihiza Glabra L, also know as Licorice root or Gan Cao in Chinese, is a commonly used perennial herb. The focus of this project was to evaluate methods of extraction of the active compound in Licorice root using small amounts of surfactant in water as a substitute for organic solvent, hence the term “solventless” extraction.  Surfactants used were SDS and Triton X.  Such a “solventless” extraction technique reduces our reliance on organic solvent, rendering the process more environmentally friendly.  

The methods involved made used of sonication extraction and pressurised fluid extraction (PFE).  PFE is a relatively new method of extraction whereby the pressure that builds up in the extraction cell is used for the extraction. The active compound extracted was determined by gradient elution High Performance Liquid Chromatography (HPLC). The optimised composition of SDS/water solution and Triton X/water solution were found to be 0.4% and 1.0% respectively. The proposed methods of extraction, Sonication with 0.4% SDS/water, had recovery from 87.58% to 105.09% and method precision was found to vary from 0.29% to 12.51%.  PFE with 0.4% SDS/water had recovery from 88.75% to 96.64% and method precision was found to vary from 1.71% to 2.62%.  PFE with 1.0% Triton X/water had recovery from 94.36% to 96.20% and method precision was found to vary from 0.59% to 1.60%. These three methods were successfully validated based on ICH and USP guidelines. They showed comparable extraction efficiencies with the reference method, being sonication with 70% organic solvent methanol.