Oxyresveratrol is a naturally occurring analog of resveratrol found in mulberry wood. It effectively scavenges H2O2, NO (IC50 = 45.3 μM), and the artificial free radical 2,2-diphenyl-l-picrylhydrazyl (IC50 = 28.9 μM). At 10 mg/kg, oxyresveratrol acts as a neuroprotectant, reducing brain infarct volume and reducing cytochrome c release and caspase-3 activation in an in vivo model of stroke. Oxyresveratrol also has depigmenting effects by effectively inhibiting tyrosinase activity, which catalyzes the rate-limiting step in synthesizing melanin pigments (IC50s = 1.2 and 52.7 μM in mushroom and mouse melanoma B-16 cells, respectively). It is 32-fold more potent than kojic acid, a depigmenting agent used in cosmetic materials with skin-whitening effects and medical agents used to treat hyperpigmentation disorders.
