Skin decolorants include tyrosinase-inhibiting skin decolorants and non-tyrosinase-inhibiting skin decolorants.
Hydroquinone in monohydric phenol and polyphenol compounds is the earliest known skin decolorant that inhibits tyrosinase. Its molecular structure is similar to that of tyrosinase substrate, which can inhibit tyrosinase activity and reduce pigmentation. However, the external preparations of phenolic compounds such as hydroquinone are unstable in chemical properties, easy to oxidize and discolor, and may also cause permanent white spots on the skin, which limits the clinical application and development of these drugs. Arbutin is a decolorizing monomer, which is isolated from the leaves of Ericaceae plants. Its molecular structure contains hydroquinone group, which is the natural form of hydroquinone. However, its inhibition of melanin production may be achieved through post-transcriptional regulation of enzyme proteins. Compared with hydroquinone, arbutin has stable chemical properties, low cytotoxicity and safe use, and has great potential for clinical application and cosmetic development.