title: Topical hypopigmenting agents for pigmentary disorders and their mechanisms of action.
abstract: Melanin is produced in melanocytes and stored in melanosomes. In spite of its beneficial sun-protective effect, abnormal accumulation of melanin results in esthetic problems. Hydroquinone, competing with tyrosine, is a major ingredient in topical pharmacological agents. However, frequent adverse reactions are amongst its major limitation. To solve this problem, several alternatives such as arbutin, kojic acid, aloesin, and 4-n-butyl resorcinol have been developed. Herein, we classify hypopigmenting agents according to their mechanism of action; a) regulation of enzyme, which is subdivided into three categories, i) regulation of transcription and maturation of tyrosinase, ii) inhibition of tyrosinase activity, and iii) post-transcriptional control of tyrosinase; b) inhibition of melanosome transfer, and c) additional mechanisms such as regulation of the melanocyte environment and antioxidant agents.
authors.affiliation: Department of Dermatology, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Hyojin
authors.initials: H
authors.lastname: Kim
authors.forename: Hye-Ryung
authors.initials: HR
authors.lastname: Choi
authors.forename: Dong-Seok
authors.initials: DS
authors.lastname: Kim
authors.forename: Kyoung-Chan
authors.initials: KC
authors.lastname: Park