Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.17.3.2 (xanthine oxidase)
 8,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Uric acid is the end product of the purine metabolism in the human and is mainly excreted to the urine. The studies on cerebrospinal fluid (CSF) uric acid in patients with various neurological diseases were reported in the literature. In the present study the authors discussed the clinical value of the sequential study of the CSF uric acid content in patients with brain tumors. CSF was investigated for uric acid in 23 controls and 30 cases of brain tumor. The results were as follows: The mean value and standard deviation of the uric acid in CSF in controls was 0.23 +/- 0.13 mg/dl. The uric acid in CSF increased in patients with malignant brain tumor (0.49 +/- 0.22 mg/dl, p less than 0.005), but was in normal range in patients with benign brain tumor (0.32 +/- 0.13 mg/dl, 0.10 less than p less than 0.25). There was no significant correlation between CSF uric acid and CSF protein contents. Uric acid in the lumbar CSF was approximately 4 times higher than in the ventricular CSF in patients with brain tumor. The CSF uric acid had progressively increased during irradiation to the whole brain. The factors contributing to increase of the uric acid in CSF were thought to be increased permeability of blood-CSF barrier, global damage of brain tissue, increased nucleic acid catabolism in the central nervous system (CNS) for example in tumor, inflammation or immunoreaction, increased of xanthine, hypoxanthine or xanthine oxidase activity in the CNS, directly increased of plasma components into the CSF due to such as subarachnoid hemorrhage, intraventricular hemorrhage, bleeding in the tumor or surgical operation, dysfunction of the CSF dynamics.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Clinical value of the sequential study of the uric acid in CSF in patients with cerebral diseases: Part I. Brain tumor and the effect of irradiation]. 674 98

The stems of Bougainvillea spectabillis Wild (Nyctaginaceae) have been used in folk medicine for hepatis, and spinasterol and quercetin were isolated and characterized from the plant leaves in this study. These constituents have not been previously isolated from Bougainvillea spectabillis W. Quercetin, the flavonoid, was found as active principle because it showed a strong activity on xanthine oxidase inhibition (IC50 = 7.23 microM) in this study as well as in the literature. Since xanthine oxidase serum levels are increased in hepatitis and tumoral brain tissues, quercetin may be used for remission of hepatitis or brain tumor. In order to study the structure-activity relationship of the flavonoids as regards xanthine oxidase inhibition, nine naturally occurring flavonoids have been tested the inhibitory effects on xanthine oxidase, such as baicalein, baicalin, capillarisin, d-catechin, d-epicatechin, hesperidin, liquiritin, puerarin and wogonin. The results showed that baicalein displayed the strongest activity (IC50 = 9.44 microM), followed by wogonin (IC50 = 52.46 microM) and then baicalin (IC50 = 71.73 microns). Baicalein induced uncompetitive inhibition of the enzyme with respect to xanhtine and the apparent inhibition constant (Ki) was 2.48 x 10(-6) M.
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PMID:Inhibitory effects of flavonoids on xanthine oxidase. 829 30

Xanthine oxidase inhibitors are known to be therapeutically useful for the treatment of hepatitis and brain tumor. Baicalein, baicalin and wogonin, isolated from Scutellaria rivularis, have been reported to exhibit a strong activity on xanthine oxidase inhibition. In this study, their antioxidant activity was evaluated by modified xanthine oxidase inhibition and cytochrome c reduced methods. The results showed that the order of activity on xanthine oxidase inhibition was baicalein > wogonin > baicalin, IC50 = 3.12, 157.38 and 215.19 microM, respectively, whereas the activity on cytochrome c reduction was baicalin > wogonin > baicalein (IC50 = 224.12, 300.10 and 370.33 microM, respectively). In another study, an electron spin resonance (ESR) technique was used to further confirm the direct free radical scavenging activity. Both baicalein and baicalin demonstrated a strong activity on eliminating the superoxide radical (.O2-) (baicalein: 7.31 x 10(4) u/g; baicalin: 1.19 x 10(5) u/g). The IC50 of baicalein was 2.8 fold higher than that of baicalin. However they had no significant effect on scavenging hydroxyl radical (.OH). The present results demonstrated that baicalein and baicalin posed a different pathological pathway. The antioxidant function of baicalin was mainly based on scavenging superoxide radical whilst baicalein was a good xanthine oxidase inhibitor.
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PMID:Antioxidant and free radical scavenging effects of baicalein, baicalin and wogonin. 1106 94