Xanthine Oxidase

Xanthine Oxidase (XO) catalyzes the oxidation of hypoxanthine to xanthine and can further catalyze the oxidation of xanthine to uric acid.

Xanthine oxidase also performs enzyme actions on several aldehydes creating carboxylic acids, an action also performed by aldehyde oxidase and aldehyde dehydrogenase (ALDH).

Xanthine oxidase converts the aldehyde vanillin into the carboxylic acid vanillic acid.

Vanillin XO Vanillic Acid
Vanillin.gif —-> Vanillic-acid.gif

Inhibitors and Inducers

Potent Inhibitors Strength Dosage Verified in Man
Allopurinol IC50 0.0307 µM[2] ? ?
Apigenin1 IC50 0.00074 µM[3] ? ?
Caffeic acid IC50 0.0654 μM[4] ? ?
Chrysin ? ? ?
Cinnamaldehyde [7] IC50 8.4 µg/mL 150mg/kg In mice orally[7]
Cuminaldehyde [9] K(i) of 120 mM2 ? ?
Ellagic Acid IC50 3.1 µM ? ?
Eugenol [8] IC50 0.3 mmol/L ? ?
Gallic Acid ? ? ?
Hesperetin ? ? ?
Hydroxychavicol IC50 0.0167 µM[2] ? ?
Luteolin IC50 0.00059 µM[3] ? ?
Propyl gallate ? ? ?
Resveratrol IC50 0.0139 µM[5] ? ?
Moderate Inhibitors Strength Dosage Verified in Man
Benzaldehyde ? ? ?
Geraniin IC50 30.49 μM[1] ? ?
Naringenin IC50 50-100 μM[6] ? ?
Inducers Strength Dosage Verified in Man
Apigenin3 ? ? ?
Rutin ? ? ?
1. Lin SY, Wang CC, Lu YL, Wu WC, Hou WC;
Antioxidant, anti-semicarbazide-sensitive amine oxidase, and anti-hypertensive activities of geraniin isolated from Phyllanthus urinaria; Department of Internal Medicine, School of Medicine, Taipei Medical University, Department of Internal Medicine, Taipei Medical University Hospital, Taipei, Taiwan; Food Chem Toxicol. 2008 Jul;46(7):2485-92. doi: 10.1016/j.fct.2008.04.007. Epub 2008 Apr 13; PubMed PMID: 18495318 (Download Attached PDF Document)
2. Murata K, Nakao K, Hirata N, Namba K, Nomi T, Kitamura Y, Moriyama K, Shintani T, Iinuma M, Matsuda H;
Hydroxychavicol: a potent xanthine oxidase inhibitor obtained from the leaves of betel, Piper betle; School of Pharmacy, Kinki University, 3-4-1 Kowakae, Higashi-osaka, Osaka, 577-8502, Japan; J Nat Med. 2009 Jul;63(3):355-9. doi: 10.1007/s11418-009-0331-y. Epub 2009 Apr 22; PubMed PMID: 19387769; Brenda Enzymes Reference Data: 705237
3. Noro T, Oda Y, Miyase T, Ueno A, Fukushima S;
Inhibitors of xanthine oxidase from the flowers and buds of Daphne genkwa; Chem Pharm Bull (Tokyo). 1983 Nov;31(11):3984-7; PubMed PMID: 6689478; Brenda Enzymes Reference Data: 673050
4. Chang YC, Lee FW, Chen CS, Huang ST, Tsai SH, Huang SH, Lin CM.
Free Radic Biol Med. 2007 Dec 1;43(11):1541-51. Epub 2007 Sep 4; Structure-activity relationship of C6-C3 phenylpropanoids on xanthine oxidase-inhibiting and free radical-scavenging activities; Department of General Surgery, Mackay Memorial Hospital, Taipei, Taiwan. PubMed PMID: 17964425; Brenda Enzymes Reference Data: 686866
5. Huang XF, Li HQ, Shi L, Xue JY, Ruan BF, Zhu HL;
Synthesis of resveratrol analogues, and evaluation of their cytotoxic and xanthine oxidase inhibitory activities; Chem Biodivers. 2008 Apr;5(4):636-42. doi: 10.1002/cbdv.200890059; Institute of Functional Biomolecules, State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, P.R. China; PubMed PMID: 18421756; Brenda Enzymes Reference Data: 686042
6. On-chip assay for determining the inhibitory effects and modes of action of drugs against xanthine oxidase.
Naoghare PK, Kwon HT, Song JM. PubMed PMID: 19679420
7. Essential oil from leaves of Cinnamomum osmophloeum acts as a xanthine oxidase inhibitor and reduces the serum uric acid levels in oxonate-induced mice.
Wang SY, Yang CW, Liao JW, Zhen WW, Chu FH, Chang ST. PubMed PMID: 18693097
8. Eugenol triggers different pathobiological effects on human oral mucosal fibroblasts.
Jeng JH, Hahn LJ, Lu FJ, Wang YJ, Kuo MY. PubMed PMID: 8006231
9. Scavenging of superoxide anions by spice principles.
Krishnakantha TP, Lokesh BR. PubMed PMID: 8394839
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