The Mechanism of Melanocytes-Specific Cytotoxicity Induced by Phenol Compounds Having a Prooxidant Effect, relating to the Appearance of Leukoderma

Figure 9

Electron spin resonance (ESR) spectra of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) adduct signals in a sample mixture of hydrogen peroxide (H₂O₂), tyrosinase, and rhododendrol (RD) irradiated with ultraviolet B (UVB) at a dose of 1000 J/m². After 100 μM RD was added to 100 units/mL tyrosinase, DMPO (20 μL) was added to the sample mixture (20 μL), which was irradiated with UVB immediately, and the radical signals were measured by ESR. (a) H₂O₂, (b) a mixture of H₂O₂ and tyrosinase, (c) a mixture of H₂O₂, tyrosinase, and RD, and (d) a mixture of H₂O₂, tyrosinase, and RD, and the mixture was irradiated with UVB.

(a) H₂O₂

(b) H₂O₂ + tyrosinase

(c) H₂O₂ + tyrosinase + RD

(d) H₂O₂ + tyrosinase + RD + 1000 J/m² UVB