Disturbance in phenylalanine hydroxylase activity during an anomaly in the biopterin cycle / 6-BH4.Epidermal H2O2 accumulation alters the tetrahydrobiopterin (6-BH4) cycle, which is recognised for its importance during the initial stages of melanin and catecholamine synthesis, which are accompanied by a fall in catalase levels. A supply of calcium and catalase reduces the level of H2O2 and regulates the biopterin cycle.
Tyrosinase is a crucial enzyme in the process of melanogenesis which ensures skin pigmentation. Tyrosinase is inhibited in the presence of free oxygen radicals (superoxide ion O2-). A supply of catalase, SOD and ginkgo biloba reduces levels of H2O2 and O2-.
Melanin whitens in the presence of oxygen radicals (.OH). A supply of catalase, SOD and ginkgo biloba helps to reduce levels of .OH.