Production and Anti-Melanoma Activity of Methoxyisoflavones from the Biotransformation of Genistein by Two Recombinant Escherichia coli Strains.

Biotransformation of the soy isoflavone genistein by sequential 3'-hydroxylation using recombinant expressing tyrosinase from and then methylation using another recombinant expressing -methyltransferase from was conducted. The results showed that two metabolites were produced from the biotransformation, identified as 5,7,4'-trihydroxy-3'-methoxyisoflavone and 5,7,3'-trihydroxy-4'-methoxyisoflavone, respectively, based on their mass and nuclear magnetic resonance spectral data. 5,7,4'-Trihydroxy-3'-methoxyisoflavone showed potent antiproliferative activity toward mouse B16 melanoma cells with an IC value of 68.