title: [Leukoderma caused by chemicals: mechanisms underlying 4-alkyl/aryl-substituted phenols- and rhododendrol-induced melanocyte loss].
abstract: Chemical leukoderma is a skin depigmentation disorder known to occur in manufactural workplace through contact with chemicals, such as monobenzyl ether of hydroquinone (MBEH) and 4-tert- butylphenol (4-TBP). In the skin depigmented -legions induced by these chemicals, the number of melanocyte was severely decreased. Anti-melanoma agent 4-cysteaminylphenol (4-SCAP) and its derivatives are also known to cause leukoderma. Evidence has accumulated supporting that typical class of chemicals causing leukoderma is "4-alkyl/aryl-substituted phenols/catechols", which are structurally similar to melanin precursor tyrosine. Tyrosinase-mediated oxidation of these chemicals yields toxic ortho-quinones which bind to cellular proteins and produce reactive oxygen species. Accordingly, this tyrosinase-dependent metabolic activation is thought to cause melanocyte-specific damage and subsequent immune reactions toward melanocytes. Recently, rhododendrol, an inhibitor of tyrosinase developed for so-called lightening/whitening cosmetics, was shown to cause leukoderma in the users. In this review, I document the causes of known chemical leukoderma and rhododendrol- induced leukoderma, focusing on their common mechanisms underlying melanocyte loss.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Nishimaki-Mogami
mesh_terms: D000818:Animals; D000440:Butanols / Q000009:adverse effects*; D004791:Enzyme Inhibitors / Q000009:adverse effects*; D006801:Humans; D006873:Hydroquinones / Q000009:adverse effects; D008544:Melanocytes / Q000187:drug effects* / Q000473:pathology*; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors / Q000502:physiology; D016273:Occupational Exposure / Q000009:adverse effects*; D010084:Oxidation-Reduction; D010636:Phenols / Q000009:adverse effects*; D010859:Pigmentation Disorders / Q000139:chemically induced*; D011817:Rabbits; D017382:Reactive Oxygen Species / Q000378:metabolism; D012871:Skin Diseases / Q000139:chemically induced*
chemical_list: D000440:Butanols; D004791:Enzyme Inhibitors; D006873:Hydroquinones; D010636:Phenols; D017382:Reactive Oxygen Species; C115945:rhododendrol; C006429:monobenzone; D014442:Monophenol Monooxygenase; C006862:butylphen