Artochalcone—A Geranylated Dihydrochalcone from Male Inflorescences of Artocarpus altilis (Breadfruit) with Potent Anti-Tyrosinase Activity

A key factor that regulates melanogenesis is the activity of tyrosinase, and inhibitors of this enzyme are used as skin-whitening and lightening agents in the skincare and cosmetics industries. The methanolic extract from male inflorescences of Artocarpus altilis (Parkinson) Fosberg (breadfruit) was investigated for its bioactivities which are important for the skincare industry, including anti-tyrosinase activity. Bioassay-guided fractionation led to the isolation of a geranylated dihydrochalcone, 2-Geranyl-2’,3,4,4’-tetrahydroxydihydrochalcone (hereinafter referred to as Artochalcone), present at 1.64% of the inflorescence dry weight. Its structure was determined by a combination of 1D and 2D-NMR and HR-ESI-MS analysis. Artochalcone was found to inhibit tyrosinase with an IC50 value of 28.4 μM, making it sixteen times more effective than the leading commercial skin-whitening agent, arbutin. In addition, Artochalcone displayed significant antioxidant activity determined by 2,2-diphenyl-1-picrylhydrazyl (IC50 = 20.4 μM) and nitric oxide scavenging assays (IC50 = 20.7 μM).