Alpha-Tocopherol (alpha-Toc) and its derivatives inhibit tyrosinase in vitro and melanogenesis in epidermal melanocytes. The antioxidant properties of alpha-Toc, which interferes with lipid peroxidation of melanocyte membranes and increases the intracellular glutathione content, could explain its depigmenting effect. Alpha-Toc has a more effective and long-lasting antioxidant response. Topical application of alpha-Toc and AsA, in vivo, […]

A disulfide derivative of octanoic acid, it exhibits several biologic effects, which include the quenching of ROS, metal chelation, interaction, and the regeneration of other antioxidants, redox regulation of protein thiol groups, and effects on gene expression and apoptosis (43). Thioctic acid has been reported to prevent UV-induced photo-oxidative damage, mainly through the down-modulation of […]

AsA is quickly oxidized and decomposed in aqueous solution and thus is not generally useful as a depigmenting agent. To resolve that problem, Magnesium-L-ascorbyl-2- phosphate (VC-PMG) was synthesized. VC-PMG is stable in water, especially in neutral or alkaline solution containing boric acid or its salt. VC-PMG is hydrolyzed by phosphatases of liver or skin to […]

Ascorbic acid (AsA) interferes with the different steps of melanization, by interacting with copper ions at the tyrosinase active site and reducing dopaquinone and DHICA oxidation. Melanin can be changed from jet black to light tan by the reduction of oxidized melanin (35). AsA is an effective reducing agent, which, at high concentrations, can momentarily […]

Compounds with redox properties can have depigmenting effects by interacting with o-quinones, thus avoiding the oxidative polymerization of melanin intermediates, or with copper at the active site. Therefore, that melanin cannot be formed by the action of tyrosinase until all ascorbic acid is oxidized.

A polyphenol widely distributed in plants, is capable of preventing pigmentation caused by sunburn (34). Ellagic acid inhibits tyrosinase non-competitively in a dose-dependent manner, through its capacity to chelate copper, even if other mechanisms, such as a scavenger effect have been suggested. Interestingly, in brownish guinea pigs (34), ellagic acid induced a reversible inhibition of […]

The licorice extract includes liquiritin, isoliquertin (a chalcone) that occurs as a glycoside and during drying is partly converted into liquiritin, liquiritigenin, isoliquiritigenin, and other compounds. Liquiritin causes depigmentation by two mechanism: (i) via melanin dispersibility by means of the pyran ring of the color dispersing flavonoidal nucleus of liquiritin, and (ii) via amelanodermic and […]

Arbutin was first discovered in Arctostapylos uva-ursi (L.) Spreng and then in the leaves of Vaccinicum vitis-idaca L., Pyrus pyrifolia (Burm. f.) Kakai. and Saxifraga stolonifera (L.) Meerb. It is a naturally occurring HQ beta-D-gluconopyranoside, which causes depigmentation at non-cytotoxic concentrations. In both normal human melanocytes and melanoma, arbutin induces a decrease of tyrosinase activity […]

Aloesin, a natural hydroxymethylchromone derivative isolated from aloe vera, acts by two different mechanisms of action on tyrosinase activity, e. g., aloesin inhibits the formation of DOPA quinone by competitive inhibition at the DOPA oxidation site, reduction of copper ions at the hydroxylase site, and consequently tyrosine hydroxylation by non­competitive inhibition (24). In comparison with […]