Effects of salicylic acid on mushroom tyrosinase and B16 melanoma cells.

Salicylic acid slightly inhibited the oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) catalyzed by mushroom tyrosinase noncompetitively without being oxidized. In contrast, 4-hydroxybenzoic acid did not inhibit this enzymatic oxidation if a longer reaction time was observed, although it suppressed the initial rate of the oxidation to a certain extent. Neither acid showed noticeable effects on cultured murine B16-F10 melanoma cells except weak cytotoxicity.