Safety of NADES Extract of Glycyrrhiza Roots After Topical Application and Peroral Administration to Mice

Natural deep eutectic solvents (NADES) have been extensively used for the extraction of a wide spectrum of plant materials. However, limited data about the in vivo toxicity of NADES extracts restrict their future practical application. In this study, we are aiming to assess the safety of a Sorbitol-lactic acid (3:1 mol./mol.; 30% water) NADES extract of Glycyrrhiza roots (GR) in mice. LC-MS/MS analysis revealed the presence of 17 metabolites, including phenolic acids, flavonoids, their glycosides, chalcones, terpene saponins, and coumarins. Interestingly, most of the identified compounds were found in higher amounts in NADES extract compared to water and EtOH extracts. No skin edema, inflammation, or erythema was observed in mice after topical application of NADES extract of GR and NADES at the doses of 50, 100, and 150 µL/mice in comparison with the control group. The calculated primary irritation index was about 0.45 both for NADES and NADES extract of GR only in high doses and falls into mild irritant categories. The individual Draize scores indicate that erythema was evident in the first three days and that all signs had disappeared by day five. No acute toxic signs or mortality of animals was observed in mice following oral administration of single doses of 4, 6, and 20 g/kg of NADES or NADES extract of GR. The NADES and extract seem to be safe at doses of up to 20 g/kg, and the LD50 was considered to be >20 g/kg. Our results open prospects for the use of NADES extract of GR for the development of transdermal and peroral formulations in the cosmetic, food, and pharmaceutical industries.