title: Major primary cytotoxic product of 4-hydroxyanisole oxidation by mushroom tyrosinase is 4-methoxy ortho benzoquinone.
abstract: It has been shown previously that the initial product of mushroom tyrosinase-catalysed oxidation of the monophenol 4-hydroxyanisole (4HA) is 4-methoxy ortho benzoquinone (4-MOB). This study presents evidence that 4-MOB is primarily responsible for the cytotoxicity of 4HA oxidation products in vitro. Equivalent toxicity in a model system was produced by products of tyrosinase catalysed oxidation of 4HA and by synthetic 4-MOB. Cytotoxicity was estimated both by a blebbing assay and by plating efficiency of exposed cells. HPLC analysis of the reaction mixture revealed a positive correlation between cytotoxicity and 4-MOB concentration.
authors.affiliation: Biology Department, Brunel University, Uxbridge, Middlesex, U.K.
authors.forename: S
authors.initials: S
authors.lastname: Naish
authors.forename: J L
authors.initials: JL
authors.lastname: Holden
authors.forename: C J
authors.initials: CJ
authors.lastname: Cooksey
authors.forename: P A
authors.initials: PA
authors.lastname: Riley
mesh_terms: D000818:Animals; D000840:Anisoles / Q000378:metabolism*; D001487:Basidiomycota / Q000201:enzymology*; D016227:Benzoquinones; D004156:Catechol Oxidase / Q000378:metabolism*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects*; D007700:Kinetics; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D010084:Oxidation-Reduction; D011809:Quinones / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000840:Anisoles; D016227:Benzoquinones; D011809:Quinones; C058960:4-methoxy-1,2-benzoquinone; C009760:mequinol; D004156:Catechol Oxidase; D014442:Monophenol Monooxygenase