Identification of tyrosinase inhibitors in cultures of Pityrosporum.

Lipid fractions capable of inhibiting the dopa-tyrosinase reaction in vitro were isolated by thin-layer chromatography from submerged cultures of Pityrosporum supplemented with oleic acid or vaccenic acid. Analysis of these fractions by gas chromatography-mass spectrometry revealed the presence mainly of C(9) and C(11) dicarboxylic acids. Standard dicarboxylic acids from C(8) to C(13) were capable of inhibiting tyrosinase in vitro to varying extents. Enzymatic kinetic studies showed that they act as competitive inhibitors of tyrosinase. These observations suggest that dicarboxylic acids could be used in the treatment of people with hyperpigmentary disorders.