The Glycyrrhiza radix (Licorice) is one of the most commonly used medicinal plants in Asian countries, such as China, India, and Korea. It has been traditionally used to treat many diseases, including cough, cold, asthma, fatigue, gastritis, and respiratory tract infections. A Glycyrrhiza new variety, Wongam (WG), has been developed by the Korea Rural Development Administration and revealed pharmacological effects. However, the potential adverse effects of WG have not been revealed yet. This study evaluates the general toxicity of the WG extract through a single and repeated oral dose toxicity study in Sprague-Dawley rats. After single oral dose administration, no significant toxicological changes or mortality was observed up to 5000 mg/kg. Over a 4-week repeated oral dose toxicity study, no adverse effects and target organs were observed up to 5000 mg/kg/day. Over a 13-week repeated oral dose toxicity study, no mortality or toxicological changes involving ophthalmology, water consumption, or hematology were observed up to 5000 mg/kg/day. Although other parameters were changed, the alterations in question were not considered toxicologically significant, since responses remained within normal ranges and were not dose-dependent. In conclusion, the no-observed-adverse-effect level (NOAEL) of WG was higher than 5000 mg/kg/day, and no target organs were identified in rats.
Keywords: 13-week repeated oral dose toxicity study; 4-week repeated oral dose toxicity study; Glycyrrhiza; Wongam; single oral dose toxicity study.