Selective Extraction of Lipophilic Bioactive Compounds from Industrial Root Meal of Glycyrrhiza glabra L.

Licorice (Glycyrrhiza glabra L.) root meal generated after industrial extraction of water-soluble constituents represents an underutilized secondary plant resource rich in lipophilic bioactive compounds. In this study, an efficient approach for the comprehensive recovery of hydrophobic biologically active substances from licorice root meal was developed. The method is based on sequential ethanol extraction followed by selective fractionation using a petroleum ether-ethyl acetate solvent system and chromatographic purification. As a result, a lipid fraction (1.1%) containing phytosterols (β-sitosterol and stigmasterol) was obtained, while the pharmacologically important isoflavan glabridin was isolated with a purity of 87.9% and a yield of 0.17%. In addition, triterpenoid aglycones, including 3-oxoglycyrrhetinic acid (0.39%) and glycyrrhetinic acid (0.21%), were successfully isolated and structurally confirmed by IR and NMR spectroscopy. Comparative solvent studies demonstrated that ethanol provides the highest extraction yield (7.1%) while maintaining high levels of glabridin and total flavonoids in the extracts. The results indicate that licorice root meal is a valuable secondary source of lipophilic bioactive compounds, and the proposed approach enables more efficient utilization of plant raw materials, reduction of industrial waste, and development of sustainable technologies for obtaining pharmacologically valuable compounds for pharmaceutical, cosmetic, and biomedical applications.