• 분석과학
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• 제36권1호
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• pp.44-52
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• 2023

This protocol clarifies a simple and precise method for measuring the activity of xanthine oxidase (XO) enzyme inhibitor. XO enzyme, which accelerates oxidative stress-related disorders through its capacity to generate hydrogen peroxide and superoxide anion radicals (O₂^•-), has been found to be inhibited by several plant extracts. Enzyme samples were incubated with a suitable buffer containing adequate amounts of xanthine as a substrate to determine XO activity. The method depends on direct measurements of uric acid and hydrogen peroxide production to test XO with and without interference. The CUPRAC reagent (Cu(Nc)₂²⁺) was used to inhibit enzyme reaction after incubation was complete. The generated urate and peroxide reduced the Cu(II)-neocuproine complex (Cu(Nc)₂²⁺) to a brightly colored Cu(I)-neocuproine complex (Cu(Nc)₂⁺), which was assessed with a spectrophotometer at 450 nm. XO activity was found to be directly related to the increased absorbance of the colored Cu(I)-neocuproine complex (Cu(Nc)₂⁺). To eliminate catalase enzyme interference, the proposed method used sodium azide and was validated against XO activity using the UV method in matched samples with t-test analysis. The proposed assay can determine XO activity with high precision, as indicated by the correlation coefficient (R² = 0.9935) from comparison with the reference protocol.

• Journal of Nutrition and Health
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• 제33권7호
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• pp.739-744
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• 2000

The purpose of this study was to elucidate protective effect of Fructus Schsandrae(FS) water extract against xanthine oxidase/hypoxanthine(XO/HX)-induced cardiotoxicity in myocardial cells this experiment was performed. Cardiotoxicity of XO/HX was examined by MTT(MTT [3-(4,5-dimethylthiazol-2-yl)-2.5,-diphenyl tetrazolium bromide) assay. XO/HX induced the decrease of cell viability. Also XO/HX induced the increase of LDH activity and the decrease of beating rate on cultured myocardial cells in a dose-dependent manner. To investigate cardioprotective effect of FS water extract cultures were preincubated with FS water extract for 3 hours. Cultures were then exposed to XO/HX for 72 hours. FS water extract have an efficacy in decreaasing LDH activity and increasing heart beating rate on cultured myocardial cells damaged by XO/HX. From the results it is suggested that XO/HX may show toxic effect in cultured myocardial cells derived from neonatal mouse and FS water extract is effective in the prevention of XO/HX-induced cardiotoxicity.

• 대한한의학회지
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• 제20권4호
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• pp.3-10
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• 2000

In order to elucidate the toxic mechanism of neurotoxical damage and neuroprotective effect of Jangwon-hwan(Zhuangyuan-wan) water extract, this experiment was performed. Neurotoxic effects of xanthine oxidase/hypoxanthine(XO/HX) were examined by MTT and NR assay, neuroprotective effects of Jangwon-hwan(Zhuangyuan-wan) water extract were examined by neurofilament enzymeimmuno assay(EIA). XO/HX induced an increase in cell viability, and a decrease in the amount of neurofilament on cultured mouse cerebral cortical neurons in dose-dependent manner. In neuroprotective effect of herb medicine, Jangwon-hwan(Zhuangyuan-wan) water extract increased the amount of neurofilament on cultured mouse cerebral cortical neurons damaged by XO/HX. From the results, it is suggested that XO/HX showed toxic effect in cultured mouse cerebral cortical Neurons and Jangwon-hwan(Zhuangyuan-wan) water extract is very effective in the prevention of neurotoxicity induced by XO/HX.

• 한국식품영양과학회지
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• 제27권4호
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• pp.739-744
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• 1998

To evaluate an effect of ethanol pretreatment on the liver xanthine oxidase(XO) activity, 0.25ml of xylene(50% in olive oil) per 100g body weight was daily given four days to the rats at 2hrs after aministration of ethanol each day, while each control group(ethanol, xylene, olive oli) was treated as the same dose described as above. The animals were sacrificed at 24hrs after last injection. Xylene-treated rats showed the more decreased activity of liver XO compared to the control. But the pretreatment of ethanol to the xylene-treated rats enhanced the liver XO activity. Furthermore, the xylene-treated rats led to more increased Vmax value in liver XO compared to the only xylene-treated rats. On the other hadn, hepatic aldehyde dehydrogenase activity was more decreased in xylene-treated rats pretreated with ethanol than in xylene-treated rats. And the intermediated xylene metabolites, methyl benzylalcohol or aldehyde inhibited the XO activity "in vitro". In conclusion, the phenomenon that pretreatment of ethanol to the xylene-treated rats led to the enhancement of liver XO activity, may be due to an influence of acetaldehyde.taldehyde.

• 대한의생명과학회지
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• 제6권1호
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• pp.37-43
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• 2000

흰쥐에 있어서 피부의 공기차단이 피부조직의 xanthine oxidase (XO) 활성에 미치는 영향을 검토하고자 직경 46 mm, 높이 10 mm인 petri dish-shaped glass chamber에 순간접착제 ($\alpha$-cyanoacrylate)를 이용하여 실험동물의 등 부위 피부조직에 부착시켜 10일간 공기의 접촉을 차단하였다. 공기 접촉 차단 5일째에 피부의 땀 축적량은 약 400 mg 정도이었으나, 10일째에는 약 25 mg으로 감소하였다. 5일간 피부차단 시 피부조직 중 XO 활성은 대조군에 비해 증가하였으며, 그 증가율은 chamber 내의 땀 축적량과 관련하여 10일간 피부차단군 보다 높게 나타났다. 5일간 피부차단 시 XO의 기질 농도 변화에 따른 반응 속도를 관찰한 결과, 대조군에 비해 V$_{max}$ 치가 높게 나타났다. 이상 실험 결과를 보아, 피부의 공기접촉 차단으로 피부조직 중 XO효소 활성이 증가된 것은 이 효소 단백 합성 유도에 기인되며, 이는 피부조직에서 oxygen free radical의 생성을 유도하여 외부 환경에 대한 방어장벽작용에 관여할 것으로 생각된다.

• Toxicological Research
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• 제11권2호
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• pp.279-288
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• 1995

To apply the serum xanthine oxidase (XO) determining for the index of the toluene intoxication, the serum XO activity was compared with the other parameters, the activities of serum alanine aminotransferase(ALT), aspartate aminotransferase(AST), 5'-nucleotidase(5'-NT), alkaline phosphatase(ALP), guanase(GDA) and $\gamma$-gIutamyl transpeptidase(T-GTP). Concomitantly, the cause of increased level of serum XO was clarified in the present experimental conditions. Although the other serum enzyme activities, ALT, AST, 5'-NT, ALP, GDA and $\gamma$-GTP were respectively not found to be different between control group and toluene-treated group, the serum XO activity in toluene-treated group showed the higher levels than that in the control group. These suggested that the determination of serum XO activity could be used for monitoring the intoxication of toluene. On the other hand, the activities of XO both in the serum and liver were higher in toluene-treated or benzaldehyde-treated rats than those in each control group. In the pooled liver XO from each group, toluene-treated or benzaldehyde-treated group showed the higher $V_{max}$ value than the control group, whereas no changes were observed in liver XO activities between the control liver specimen and that preincubated with bertzaldehyde in vitro. The present results indicate that the increased level of XO in toluene-treated rats is due to the result of enzyme protein induction in liver cell by the benzaldehyde metabolized from toluene. All the more, the benzaldehyde may be acted as a substrate for XO, since the benzaldehyde induced the increased activity of both liver and serum XO, and no changes were found in purine catabolite, uric acid in serum or urine and liver purine catabolizing enzymes, adenosine deaminase, GDA, uricuse except XO in toluene-treated rats.

• 대한의생명과학회지
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• 제12권4호
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• pp.439-442
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• 2006

To evaluate the postmortem changes in activities of oxygen free radical metabolizing enzymes, the rats were sacrificed with cervical dislocation and were kept in an incubator at $25^{\circ}C$, 70% of humidity for 12 hours. The activities of aniline hydroxylase, catalase, glutathione-S-transferase and superoxlde dismutase were decreased with the time. On the other hand, the activity and type conversion ratio (type D ${\to}$type O) of hepatic xanthine oxidase (XO) were gradually increased. From these changes of XO, the estimation of death time (mathematical equation) could be determined with the least square method. To clarify the cause of increasing XO activity, enzyme kinetics were examined. The Km values of XO were decreased with the time. In conclusion, the determination of liver XO activity might be used for the estimation of death time in the early postmortem period.

• 대한한의학회지
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• 제21권1호
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• pp.29-39
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• 2000

In order to elucidate the toxic mechanism of oxygen radicals in cultured mouse spinal sensory neurons, cytotoxic effect of oxygen radicals was evaluated by M1T assay and NR assay. In addition, protective effect of Sopunghwalhyultang(SPHHT) water extract on oxidant-induced neurotoxicity was investigated on these cultures. Spinal sensory neurons derived from mice were cultured in mediums containing various concentrations of Xanthine Oxidase / Hypoxanthine(XO/HX). Cell viability was measured by MTT assay and NR assay. XO/HX-mediated oxygen radicals remarkably decreased cell viability of cultured spinal sensory neurons in a dose-and time-dependent manner. And also, SPHHT blocked XO/HX-induced neurotoxicity in these cultures. These results suggest that oxygen radicals are toxic and SPHHT are effective in blocking against the oxidant-induced neurotoxicity in cultures of spinal sensory neurons of mice.

• 대한의생명과학회지
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• 제1권1호
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• pp.37-43
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• 1995

사염화탄소에의한 간손상시 $CCl_4$대사에 xanthine oxidase(XO)가 관련되는지를 규명하기위한 일환으로 allopurinol을 흰쥐 체중 Kg당 50mg을 전처치한다음 $CCl_4$를 투여한 후 처치하여 다음과 같은 결과를 얻었다. $CCl_4$투여로 인한 간조직의 postmitochondria 분획의 XO활성은 allopurinol을 전처치하므로서 현저히 감소되었으나 투석한 경우에는 오히려 증가되었으며 type D로부터 type O로의 전환율은 감소되었다. 또한, 투석한 간조직의 XO를 반응속도적인 측면에서 관찰해 볼 때 allopurinol을 전처치후 $CCl_4$투여군이 $CCl_4$단독투여 군보다 Vmax가 크게 나타났다. $CCl_4$투여로 인한 체중당 간무게의 증가율과 혈청 alanine aminotransferase활성증가율은 allopurinol을 전처치하므로서 저하되었다. 한편 $CCl_4$투여로 인한 간조직중 aniline hydroxylase및 glucose 6 phosphatase활성 감소율은 allopurinol을 전처치하므로서 저하되었다. 이상의 실험결과를 종합하여 볼때 실험동물에 $CCl_4$와 allopurinol을 병행 투여시 allopurinol이 사염화탄소에 의한 간손상을 억제시키는 현상은 XO와 사염화탄소 대사간에 관련성이 있음을 시사해주고 있다.

• 대한의생명과학회지
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• 제8권3호
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• pp.155-159
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• 2002

To evaluate the physiological significance of xanthine oxidase (XO) in rat skin, the activity of XO (type O) in skin was compared with that of small intestine or liver. Concomitantly, XO activities in some partial portions (scalp, leg, dorsal and ventral part) of skin were determined and then compared with each partial portion. XO activity of skin was lower than that of small intestine and rather higher than that of liver. Furthermore, the activity of XO in skin, after clipping of hairs and then in 5 days, was more increased than that of rat which was clipped before having been sacrificed. As for activities of free radical scavenging system (GPx, GST, SOD), skin is lower than liver and small intestine. Although it is hewn that the oxygen free radical generated by XO system lead to injurious effect on the cell, the XO activity of ventral part which is to be less exposed to xenobiotics and biological agents was the lowest among those of ventral, dorsal, leg and scalp parts in skin. In conclusion, it may be hypothesized that XO system in skin act on defence mechanism.