Glutathione may help to whiten the skin because it reduce free radicals in the body that activate enzyme Tyrosinase which causes an increase in melanin (skin pigment) production. (fullhealthsecrets.com)
Quercetin [5], found in apple peel, has been shown to inhibit the pigment - producing enzyme tyrosinase, curbing the overproduction of melanin. (truebotanicals.com)
People with OCA1 have mutations in a gene called TYR that is responsible for production of the enzyme tyrosinase, used by cells to convert the amino acid tyrosine into pigment. (scientificamerican.com)