title: Xanthine oxidase inhibitory activity of nicotino/isonicotinohydrazides: A systematic approach from in vitro, in silico to in vivo studies.
abstract: Change in life style and eating habits has led to an increased prevalence of hyperuricemia worldwide. The role of hyperuricemia is no more restricted to gout, but it has a central role in progression of CVD, hypertension, metabolic syndrome, and arthritis. Among the different factors involved in regulation of serum uric acid, xanthine oxidase (XO) is the best pharmacological target to control the levels of serum uric acid as it catalyzes the final steps in uric acid production. In the current study, a systemic search for the inhibitors of xanthine oxidase, starting from synthesis to in vitro screening and leading to in vivo studies is presented. Benzylidene nicotino/isonicotinohydrazides (1-54) were synthesized by treating nicotinic/isonicotinic hydrazides with substituted aromatic aldehyde, and characterized by EI-MS and1H NMR. Elemental analysis was also performed. All synthetic compounds were screened for xanthine oxidase inhibitory activity initially using an in vitro spectroscopic XO inhibition assay. Among them twenty-two derivatives were found to be active with IC50values between 0.96 and 330.4μM, as compared to standard drug allopurinol IC50=2.00±0.01μM. Kinetic studies of five most active compounds (8, 35, 36, 39, and 45) with low IC50values between 0.96 and 54.8μM showed a competitive mode of inhibition. Further in silico molecular docking was carried out to study the interactions of these inhibitors with catalytically important amino acid residues in XO. Three compounds 8, 35, and 36 with IC50values of 10, 12.4, and 0.96μM, respectively, were also found to be non-cytotoxic, and thus selected for in vivo studies. A simple and physiologically relevant animal model was used to analyze the in vivo XO inhibitory activity of these compounds. Among these, two compounds 35, and 36 showed a significant inhibition in male Wistar rats, and identified as potential lead molecules for anti-hyperuricemic drug development.
authors.affiliation: H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan. Electronic address: hamramalik@gmail.com.
authors.forename: Humaira
authors.initials: H
authors.lastname: Zafar
authors.affiliation: Department of Chemistry, University of Karachi, Karachi 75270, Pakistan.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Hayat
authors.affiliation: Department of Chemistry, University of Karachi, Karachi 75270, Pakistan.
authors.forename: Sumayya
authors.initials: S
authors.lastname: Saied
authors.affiliation: Department of Chemistry, Abdul Wali Khan University, Mardan 23200, Pakistan.
authors.forename: Momin
authors.initials: M
authors.lastname: Khan
authors.affiliation: H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan.
authors.forename: Uzma
authors.initials: U
authors.lastname: Salar
authors.affiliation: H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan.
authors.forename: Rizwana
authors.initials: R
authors.lastname: Malik
authors.affiliation: H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan; Department of Biochemistry, Faculty of Sciences, King Abdulaziz University, Jeddah 21412, Saudi Arabia.
authors.forename: M Iqbal
authors.initials: MI
authors.lastname: Choudhary
authors.affiliation: H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan. Electronic address: khalid.khan@iccs.edu.
authors.forename: Khalid Mohammed
authors.initials: KM
authors.lastname: Khan
mesh_terms: D003198:Computer Simulation; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D066298:In Vitro Techniques; D007700:Kinetics; D009538:Nicotine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D014969:Xanthine Oxidase / Q000037:antagonists & inhibitors*
chemical_list: D004791:Enzyme Inhibitors; D009538:Nicotine; D014969:Xanthine Oxidase
keywords: Benzylidene; Gout; Hydrazides; Hyperuricemia; In silico, in vivo studies; In vitro; Xanthine oxidase inhibitors