Hexylresorcinol

IC50: 1.24 μM

Hexylresorcinol is a mushroom tyrosinase inhibitor.

Tyrosinase, a copper-containing enzyme, is distributed in microorganisms, animals, and plants widely. Mushroom tyrosinase has been becoming popular due to its availability and usages in various applications.

In vitro: Previous results showed hexylresorcinol could inhibit both mono- and di-phenolase activity of mushroom tyrosinase. Moreover, hexylresorcinol at 2 μM lengthened the lag period from 98 s to 26. Hexylresorcinol could also display reversible inhibition of the enzyme. In addition, the kinetic analyses showed that hexylresorcinol was a competitive inhibitor with the apparent inhibition constant binding with free enzyme to be 0.443 μM for diphenolase [1].

In vivo: Previous in vivo study showed that hexylresorcinol could induce chromosome aberrations in mouse eukaryotic cells at doses of 0.5, 0.05, and 0.005 mg/g and the metabolic transformation of hexylresorcinol decreased its genotoxic effect in mice. Moreover, the mutagenic effect lasted for 3 days only at the highest dose of hexylresorcinol (0.5 mg/g). Thus, hexylresorcinol doses less than 0.5 mg/g were metabolized within two days to the extent of the cytotoxic effect. In addition, hexylresorcinol was transformed at a rate of 0.0025–0.025 mg/day after a single administration to mice [2].

Clinical trial: Hexylresorcinol is clinically available for topically use on small skin infections, or as an ingredient in throat lozenges. Johnson & Johnson has marketed hexylresorcinol in its skincare products as an anti-aging cream (https://en.wikipedia.org/wiki/Hexylresorcinol).

References:
[1] Chen QX,Ke LN,Song KK,Huang H,Liu XD.  Inhibitory effects of hexylresorcinol and dodecylresorcinol on mushroom (Agaricus bisporus) tyrosinase. Protein J.2004 Feb;23(2):135-41.
[2] Margulis AB,Ozhiganova IV,Bushmanova OV,Kolpakov AI,Il'inskaia ON.  Hexylresorcinol induces chromosome aberrations in mouse peripheral blood cells. Genetika. 2005 Aug;41(8):1045-8.