Y-700 [1-[3-Cyano-4-(2,2-dimethylpropoxy)phenyl]-1H-pyrazole-4-carboxylic Acid]: A Potent Xanthine Oxidoreductase Inhibitor with Hepatic Excretion

Abstract

Y-700 (1-[3-Cyano-4-(2,2-dimethylpropoxy)phenyl]-1H-pyrazole-4-carboxylic acid) is a newly synthesized inhibitor of xanthine oxidoreductase (XOR). Steady-state kinetics with the bovine milk enzyme indicated a mixed type inhibition with K i and K i Ј values of 0.6 and 3.2 nM, respectively. Titration experiments showed that Y-700 bound tightly both to the active sulfo-form and to the inactive desulfo-form of the enzyme with K d values of 0.9 and 2.8 nM, respectively. X-ray crystallographic analysis of the enzyme-inhibitor complex revealed that Y-700 closely interacts with the channel leading to the molybdenum-pterin active site but does not directly coordinate to the molybdenum ion. In oxonate-treated rats, orally administered Y-700 (1-10 mg/kg) dose dependently lowered plasma urate levels. At a dose of 10 mg/kg, the hypouricemic action of Y-700 was more potent and of longer duration than that of 4-hydroxypyrazolo(3,4-d)pyrimidine, whereas its action was approximately equivalent to that of 2-(3-cyano-4-isobutoxyphenyl)-4-methyl-5-thiazolecarboxylic acid, a nonpurine inhibitor of XOR. In normal rats, orally administered Y-700 (0.3-3 mg/kg) dose dependently reduced the urinary excretion of urate and allantoin, accompanied by an increase in the excretion of hypoxanthine and xanthine. Y-700 (1 mg/kg) was absorbed rapidly by the oral route with high bioavailability (84.1%). Y-700 was hardly excreted via the kidneys but was mainly cleared via the liver. These results suggest that Y-700 will be a promising candidate for the treatment of hyperuricemia and other diseases in which XOR may be involved.XOR catalyzes the hydroxylation of hypoxanthine and xanthine, the last two steps in urate biosynthesis. The enzyme is found in a wide range of organisms from bacteria to man. It exists as a homodimer, each subunit of which contains one molybdo-pterin cofactor, two iron-sulfur clusters, and one FAD molecule (Bray, 1975;Hille, 1996). Mammalian XOR is synthesized as the dehydrogenase form, XDH (EC 1.1.1.204), and exists mostly as such in the cell, but can be readily converted to the oxidase form, XO (EC 1.1.3.22), by oxidation of sulfhydryl residues or by proteolysis (Nishino, 1994;Hille and Nishino, 1995). XDH displays a preference for NAD ϩ reduction at the FAD site, whereas XO fails to react with NAD ϩ and exclusively uses molecular oxygen as its substrate, leading to the formation of superoxide anion and hydrogen peroxide (Hille and Nishino, 1995).XOR is a target of drugs against gout and hyperuricemia ( Rundles et al., 1969), and the conversion of XDH to XO is of major interest because it has been implicated in diseases characterized by superoxide anion-induced tissue damage, such as postischemic-reperfusion injury (McCord, 1985). Allopurinol (Fig. 1), a purine analog, is a well-known inhibitor

Therapeutic Effects of Xanthine Oxidase Inhibitors: Renaissance Half a Century after the Discovery of Allopurinol

“…There are a few structural classes of compounds that are many hundreds times more potent than allopurinol in vitro (both of a purine and nonpurine types). Several drug candidates are either in the development phase or are moving toward clinical testing (Borges et al, 2002;Naito et al, 2000;Okamoto et al, 2003;Nivorozhkin et al, 2003a,b;Yamamoto, 2003;Mabley et al, 2003;Becker et al, 2004;Fukunari et al, 2004;Hoshide et al, 2004;Komoriya et al, 2004;Yamada et al, 2004;Hashimoto et al, 2005;Mayer et al, 2005;Takano et al, 2005). It was clearly established that a xanthine-like structural framework is not a prerequisite for high inhibitory activity.…”

FYX-051: A Novel and Potent Hybrid-Type Inhibitor of Xanthine Oxidoreductase

“…1A) has been developed as another new type of XOR inhibitor. It not only forms a covalent linkage to molybdenum via oxygen in the hydroxylation reaction intermediate, but also interacts with amino acid residues of the solvent channel, such as the structure-based inhibitor TEI-6720 (Okamoto et al, 2003 or 1-[3-cyano-4-(2,2-dimethylpropoxy) phenyl]-1H-pyrazole-4-carboxylic acid (Y-700) (Fukunari et al, 2004) (Fig. 1B).…”

Y-700, a Novel Inhibitor of Xanthine Oxidase, Suppresses the Development of Colon Aberrant Crypt Foci and Cell Proliferation in 1,2-Dimethylhydrazine-Treated Mice

“…11) In contrast, even at the high concentration of 100 mmol/l, Y-700 did not scavenge stable free radicals generated by 1,1-diphenyl-2-picrylhydrazyl (Fukunari et al, unpublished data). In rats receiving an injection of Y-700, Y-700 existed in plasma in unchanged form, indicating no evidence of any major circulating metabolites.…”

“…10,11) Y-700 possesses no oxygen-radical scavenging activity. Y-700 possesses no oxygen-radical scavenging activity (Fukunari et al, unpublished data).…”

“…In rats receiving an injection of Y-700, Y-700 existed in plasma in unchanged form, indicating no evidence of any major circulating metabolites. 11) Comprehensive study of the metabolism of Y- Each value is mean AE SE (n ¼ 6{7). Ã Significantly different from control group (P < 0:05) by Student's t-test.…”