Anti-Melanogenic Properties of Velutin and Its Analogs †

Velutin, one of the flavones contained in natural plants, has various beneficial activities, such as skin whitening, as well as anti-inflammatory, anti-allergic, antioxidant, and antimicrobial activities. However, the relationship between the structure of velutin and its anti-melanogenesis activity is not yet investigated. In this study, we obtained 12 velutin derivatives substituted at C5, C7, C3′, and C4′ of the flavone backbone with hydrogen, hydroxyl, and methoxy functionalities by chemical synthesis, to perform SAR analysis of velutin structural analogues. The SAR study revealed that the substitution of functional groups at C5, C7, C3′, and C4′ of the flavone backbone affects biological activities related to melanin synthesis. The coexistence of hydroxyl and methoxy at the C5 and C7 position is essential for inhibiting tyrosinase activity. However, 1,2-diol compounds substituted at C3′ and C4′ of flavone backbone induce apoptosis of melanoma cells. Further, substitution at C3′ and C4′ with methoxy or hydrogen is essential for inhibiting melanogenesis. Thus, this study would be helpful for the development of natural-derived functional materials to regulate melanin synthesis.