Byung-Mu Lee has his expertise in development of anti-aging and anti-inflammation agents. He is also interested in chemoprevention and risk assessment. He is Associate Editor of the Journal of Toxicology and Environmental Health A, Food and Chemical Toxicology, and Editorial review board of Environmental Health Perspectives (EHP), and Advisory Editor of Archives of Toxicology. He was the president of the 13th International Congress of Toxicology (ICT XIII) in 2013. He was the vice president of International Association of Environmental Mutagenesis and Genomics Society (IAEMGS). He was the vice president of the Asia Society of Toxicology (ASIATOX).


Among many environmental factors, solar ultraviolet irradiation is considered the main cause of skin aging in humans. In this study, the protective effect of ammonium glycyrrhizate (AG), an active component of Licorice root, on UVA- and UVB-induced phototoxicity was investigated. The antioxidant phytochemical AG has been reported to have various pharmacological properties including cardioprotective, anti-inflammatory, and soothing effects on sensitive skin. Despite the known therapeutic effect of AG, the molecular mechanisms related to the photoprotection of AG against UV-induced oxidative cell damage has not yet been determined. In UVB-irradiated HaCaT keratinocytes, AG inhibited both oxidative stress and the apoptosis signaling pathway. In addition, AG promoted the activities of the antioxidant enzymes heme oxygenase-1 (HO-1), glutathione peroxidase 1/2 (Gpx1/2), and superoxide dismutase 2 (SOD2) by translocating nuclear factor (erythroid-derived 2)-like 2 (Nrf2) in the nucleus. In UVA-irradiated human dermal fibroblasts, AG suppressed the expression of secreted matrix metalloproteinase (MMP)-1 and -9 by inhibiting the activator protein-1 (AP-1) transcription factor. Furthermore, AG remarkably increased the synthesis of pro-collagen in human dermal fibroblasts (HDF). These results suggest that AG has protective effects against UVA- and UVB-induced photoaging and should be considered a potential therapeutic agent against phototoxicity in skin.