Synthesis and evaluation of 1-hydroxy/methoxy-4-methyl-2-phenyl-1 H-imidazole-5-carboxylic acid derivatives as non-purine xanthine oxidase inhibitors

Article abstract of DOI:10.1016/j.ejmech.2015.08.056

Xanthine oxidase is a key enzyme that catalyses hypoxanthine and xanthine to uric acid, whose overproduction leads to the gout-causing hyperuricemia. In this study, a series of 1-hydroxy/methoxy-4-methyl-2-phenyl-1H-imidazole-5-carboxylic acid derivatives (4ae4k and 6ae6k) was synthesized and evaluated for their inhibitory potency against xanthine oxidase. The 1-hydroxyl substituted derivatives 4ae4k showed excellent inhibitory potency with IC₅₀ values ranging from 0.003 μM to 1.2 μM, with compounds 4d (IC₅₀= 0.003 μM), 4e (IC₅₀ = 0.003 μM), and 4f (IC₅₀ = 0.006 μM) manifesting the most potent xanthine oxidase inhibitory potency that were comparable with that of Febuxostat (IC₅₀ = 0.01 μM). LineweavereBurk plot analysis revealed that representative compound 4f acted as a mixed-type inhibitor for xanthine oxidase. The basis of significant inhibition of xanthine oxidase by 4f was rationalized by its molecular docking into the active site of xanthine dehydrogenase.