Aloesin molecule

Aloesin, a natural hydroxymethyl chromone compound isolated from the aloe vera plant) with structure is rather similar to flavonols.

It has been proven to competitively inhibit tyrosinase from human, mushroom, and murine sources. Studies have shown that tyrosine hydroxylase and DOPA (3,4-dihydroxyphenylalanine) oxidase activities (of tyrosinase from normal human melanocyte cell lysates) are inhibited by aloesin in a dose-dependent manner. The topical application of aloesin on UV-irradiated (210 mJ) human volar forearm (four times a day for 15 days) showed pigmentation suppression in a dose-dependent manner.

The hydrophilic nature of the compound reduces the skin penetration of aloesin. Hence, combination treatment of aloesin with arbutin has been observed to synergistically inhibit melanin production by combined mechanisms of noncompetitive and competitive inhibitions of tyrosinase activity.

Testing of aloesin revealed no cytotoxicity, which makes it a good alternative to HQ.