title: Effect of commonly used organic solvents on aldehyde oxidase-mediated vanillin, phthalazine and methotrexate oxidation in human, rat and mouse liver subcellular fractions.
abstract: 1. Aldehyde oxidase (AOX) is a cytosolic molybdoflavoprotein enzyme widely distributed across many tissues. In this study, we report the effect of commonly used organic solvents such as dimethyl sulfoxide (DMSO), acetonitrile (ACN), methanol and ethanol on AOX activity in human, rat and mouse liver S9 fractions using vanillin, phthalazine and methotrexate as probe substrates. 2. Methanol was found to be the most potent solvent in inhibiting vanillic acid and 1-phthalazinone formation in comparison to DMSO, ACN and ethanol across the species tested, except 7-hydroxy methotrexate. 3. Treatment with these solvents at approximate IC50 (% v/v) concentrations showed significant reduction in Clint and Vmax of the probe substrates and also resulted in different effects on Km across the species. 4. Marked differences in the activity and affinity towards AOX were observed with different probe substrates with methotrexate showing least activity and affinity as compared to vanillin and phthalazine. 5. Overall, AOX activity seemed to be more resilient to the presence of organic solvents at higher concentrations in human and rodent species. These results suggest that low concentrations of organic solvents are acceptable for in vitro incubations involving AOX-mediated metabolism.
authors.affiliation: Drug metabolism and pharmacokinetics, Glenmark Pharmaceuticals Ltd, Glenmark Research Centre , MIDC, Mahape, Navi Mumbai , India.
authors.forename: Dayanidhi
authors.initials: D
authors.lastname: Behera
authors.forename: Rambabu
authors.initials: R
authors.lastname: Pattem
authors.forename: Girish
authors.initials: G
authors.lastname: Gudi
mesh_terms: D042931:Aldehyde Oxidase / Q000378:metabolism*; D000818:Animals; D001547:Benzaldehydes / Q000737:chemistry / Q000378:metabolism*; D002853:Chromatography, Liquid; D005260:Female; D006801:Humans; D020128:Inhibitory Concentration 50; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D008727:Methotrexate / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D009930:Organic Chemicals / Q000494:pharmacology*; D010084:Oxidation-Reduction / Q000187:drug effects; D010793:Phthalazines / Q000737:chemistry / Q000378:metabolism*; D017207:Rats, Sprague-Dawley; D012997:Solvents / Q000494:pharmacology*; D021241:Spectrometry, Mass, Electrospray Ionization; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D013997:Time Factors
chemical_list: D001547:Benzaldehydes; D009930:Organic Chemicals; D010793:Phthalazines; D012997:Solvents; C043388:phthalazine; C100058:vanillin; D042931:Aldehyde Oxidase; D008727:Methotrexate
keywords: Aldehyde oxidase; IC50; LC/MS/MS; cytochrome P450; methotrexate; organic solvents; phthalazine; vanillin