Physicochemical characteristics and in vitro bioavailability of licorice (Glycyrrhiza glabra L.) extract complexed using cyclic glucans

Abstract

Licorice extract (LE), whose main ingredient is glabridin (GL), have various biological properties such as antioxidant and anticancer activities, however, their low solubility and bioavailability limit their application in the pharmaceutical and food industries. In this study, inclusion complexes (ICs) were developed using β-cyclodextrin (CD), 2-hydroxypropyl-β-cyclodextrin (HP), and cycloamylose (CA) to overcome the application limits of LE. The IC with cyclic glucans successfully enhanced the phase solubility of LE, and the stoichiometry of the complexes was investigated. After in vitro digestion, the bioaccessibility (% retention) of LE increased significantly in the IC samples, particularly with CA, compared to free LE. In vitro bioavailability, which was assessed using the results of bioaccessibility via the simulated gastrointestinal tract (GIT) model and permeability via Caco-2 monolayer assay, increased 2.5, 2.3, and 4.7-fold in the CD, HP, and CA ICs, respectively. This study provides a promising strategy to overcome the application limits of LE in various industries.