Applicability of Licorice Extracts for Treatment of Oral Diseases, Evaluated by Simplified In Vitro Assay Systems with Oral Cells

Abstract

Licorice extracts contain various useful substances for oral health. Alkaline extract showed potent anti-HIV activity, whereas flavonoid-rich water extracts showed potent anti-HSV activity, closely correlated with polarizability, ionization potential, a number of ring systems, atomic number and mass. Licorice flavonoids showed higher tumor-specificity against human oral squamous cell carcinoma as compared with human normal oral mesenchymal cells. Glycyrrhiza, at noncytotoxic concentrations, potently inhibited the IL-1β-induced inflammation in cultured human gingival and periodontal ligament fibroblasts. Glycyrrhizin, a major component of Glycyrrhiza, showed the highest UVprotected activity. The results suggest the possible applicability of licorice extracts for several oral diseases and cosmetic products.