Anti-tyrosinase and anti-melanogenic potential of shallots (Allium ascalonicum) from various cultivation sites in Thailand

The present study aimed to investigate the anti-tyrosinase effect of shallots ( Allium ascalonicum ) in Thailand and to prepare an optimised shallot extract for use as a skin-lightening agent. Aqueous and ethanolic shallot extracts from 14 cultivation sites were investigated for anti-tyrosinase effect and cytotoxicity. Shallots from Phayao exhibited low cytotoxicity and a high tyrosinase inhibitory effect, and therefore, were selected for the preparation of optimised shallot extract, AA 20-4-40. Cytotoxicity and genotoxicity of the extract were not observed in human dermal fibroblast cells treated with the extract at 1–10 mg/ml. The extract also decreased both mushroom tyrosine activity and intracellular tyrosinase activity in B16F10 cells. In addition, the extract significantly decreased melanin content in cells. These results indicated that AA 20-4-40 has the potential to be used as a skin-lightening agent in cosmeceuticals.