Inhibition of Xanthine Oxidase Activity by Gnaphalium Affine Extract

Objective To evaluate the inhibitory effect of Gnaphalium affine extracts on xanthine oxidase(XO) activity in vitro and to analyze the mechanism of this effect. Methods In this in vitro study, Kinetic measurements were performed in 4 different inhibitor concentrations and 5 different xanthine concentrations(60, 100, 200, 300, 400 μmol/L). Dixon and Lineweaver-Burk plot analysis were used to determine Ki values and the inhibition mode for the compounds isolated from Gnaphalium affine extract. Results Four potent xanthine oxidase inhibitors were found in 95% ethanolic(v/v) Gnaphalium affine extract. Among them, the f lavone Eupatilin exhibited the strongest inhibitory effect on XO with a inhibition constant(Ki) of 0.37 μmol/L, lower than the Ki of allopurinol(4.56 mol/L), a known synthetic XO inhibitor. Apigenin(Ki of 0.56 μmol/L, a proportion of 0.0053‰ in Gnaphalium affine), luteolin(Ki of 2.63 μmol/L, 0.0032‰ in Gnaphalium affine) and 5-hydroxy-6,7,3',4'-tetramethoxyflavone(Ki of 3.15 μmol/L, 0.0043‰ in Gnaphalium affine) also contributed to the inhibitory effect of Gnaphalium affine extract on XO activity. Conclusions These results suggest that the use of Gnaphalium affine in the treatment of gout could be attributed to its inhibitory effect on XO. This study provides a rational basis for the traditional use of Gnaphalium affine against gout.

Xanthine oxidase inhibitors from Archidendron clypearia(Jack.) I.C. Nielsen: Results from systematic screening of Vietnamese medicinal plants

Objective: To screen Vietnamese medicinal plants for xanthine oxidase(XO) inhibitory activity and to isolate XO inhibitor(s) from the most active plant. Methods: The plants materials were extracted by methanol. The active plant materials were fractionated using different organic solvents, including n-hexane, ethyl acetate, and n-butanol. Bioassay-guided fractionation and column chromatography were used to isolate compounds. The compounds structures were elucidated by analysis of spectroscopic data, including IR, MS, and NMR. Results: Three hundreds and eleven methanol extracts(CME) belonging to 301 Vietnamese herbs were screened for XO inhibitory activity. Among these plants, 57 extracts displayed XO inhibitory activity at 100 μg/m L with inhibition rates of over 50%. The extracts of Archidendron clypearia, Smilax poilanei, Linociera ramiflora and Passiflora foetida exhibited the greatest potency with IC_(50) values below 30 μg/m L. Chemical study performed on the extract of Archidendron clypearia resulted in the isolation of six compounds, including 1-octacosanol, docosenoic acid, daucosterol, methyl gallate, quercitrin and(-)-7-O-galloyltricetiflavan. The compound(-)-7-O-galloyltricetiflavan showed the most potent XO inhibitory activity with an IC_(50) value of 25.5 μmol/L. Conclusions: From this investigation, four Vietnamese medicinal plants were identified to have XO inhibitory effects with IC_(50) values of the methanol extracts below 30 μg/m L. Compound(-)-7-O-galloyltricetiflavan was identified as an XO inhibitor from Archidendron clypearia with IC_(50) value of 25.5 μmol/L.

Identifi cation of egg protein-derived peptides as xanthine oxidase inhibitors:virtual hydrolysis,molecular docking,and in vitro activity evaluation

The purpose of this study was to screen the xanthine oxidase(XO)inhibitory peptides from egg white proteins through virtual hydrolysis,in vitro activity validation,and molecular docking.The results demonstrated that tripeptide EEK from ovalbumin exhibited potent XO inhibitory activity with an IC50 value of 141μmol/L.The molecular docking results showed that tripeptide EEK bound with the active center of XO via 3 carbon hydrogen bond interactions,2 salt bridges,5 conventional hydrogen bond interactions,and 4 attractive charge interactions.The residues Glu802,Phe1009,and Arg880 may play key roles in the XO catalytic reaction.Especially,the key intermolecular forces of inhibiting XO activity may be special type of hydrogen bonds including carbon hydrogen bond interactions and attraction charge interactions.The novel tripeptide EEK is potential candidates for controlling hyperuricemia.

Study of Xanthine Oxidase Activity in Sera of Iraqi Children with Nephrotic Syndrome

Introduction: To investigate the relationship of xanthine oxidase activity with nephrotic syndrome disorder in children, and the optimization of the enzyme activity conditions in the disorder. Material and methods: Sera of children with nephrotic syndrome (NS) (60 samples) were obtained from Central Child Teaching Al Karama Hospital (CCTAH), from 2nd Mar. 2013 to 28th Feb. 2014. Sera of the patients were assayed for xanthine oxidase (XO) activity using colorimetric absorbance technique. The obtained results were compared with the enzyme activity of normal children (70 samples) as control. Results and conclusions: The results revealed a significant (P < 0.001) elevation in XO activity in serum of nephrotic syndrome (0.12 ± 0.06 IU/L) compared with that of normal subjects (0.05 ± 0.009 IU/L), showing an elevation of (70%) in XO activity (about 2/3) that of normal group. Factors influencing XO activities were also studied and showed that XO activity is a pH dependent. Significant elevation (P < 0.001) was found in uric acid level in sera of NS patients (497.52 ± 3.21 μmol/L) compared with that in normal group (298.12 ± 1.70 μmol/L). Elevation was found in urea level in sera of NS patient (10.69 ± 7.55 mmol/L) compared with that of normal group (4.57 ± 1.27 mmol/L). It was appeared, there is a role of XO activity in the pathogenesis of endothelial injury during glomerular lesion in NS and that was confirmed by comparing XO activity and other related conditions with the activity of normal volunteers.

A Sensitive Reversed-Phase High-Performance Liquid Chromatography Method for the Quantitative Determination of Milk Xanthine Oxidase Activity

A new reversed-phase high performance liquid chromatography method was developed to quantitate the activity of xanthine oxidase involved in milk fat globule membrane with xanthine as the substrate and the separation of product (uric acid). The increment of uric acid in the reaction system was used to calculate the total activity of XO. The optimized assay conditions, linearity of detection, recovery of uric acid and chromatogram were developed in text, indicating this method is simple, rapid and efficient. It is an alternative potential method for the determination of the activity of XO in milk.

Determination of inhibitory activity of Salvia miltiorrhiza extracts on xanthine oxidase with a paper-based analytical device

A novel paper-based analytical device(PAD)was prepared and applied to determine the xanthine oxidase(XOD)inhibitory activity of Salvia miltiorrhiza extracts(SME).First,polycaprolactone was 3D printed on filter paper and heated to form hydrophobic barriers.Then the modified paper was cut according to the specific design.Necessary reagents including XOD for the colorimetric assay were immobilized on two separate pieces of paper.By simply adding phosphate buffer,the reaction was performed on the double-layer PAD.Quantitative results were obtained by analyzing the color intensity with the specialized device system(consisting of a smartphone,a detection box and sandwich plates).The 3Dprinted detection box was small,with a size of 9.0 cm×7.0 cm×11.5 cm.Color component G performed well in terms of linearity and detection limits and thus was identified as the index.The reaction conditions were optimized using a definitive screening design.Moreover,a 10%glycerol solution was found to be a suitable stabilizer.When the stabilizer was added,the activity of XOD could be maintained for at least 15 days under 4℃ or-20℃ storage conditions.The inhibitory activity of SME was investigated and compared to that of allopurinol.The results obtained with the PAD showed agreement with those obtained with the microplate method.In conclusion,the proposed PAD method is simple,accurate and has a potential for point-of-care testing.It also holds promise for use in rapid quality testing of medicinal herbs,intermediate products,and preparations of traditional Chinese medicines.

Study the effect of kidney stones on serum xanthine oxidase, ecto-5'-nucleotidase activity and E3 SUMO-protein ligase NSE2(NSMCE2) in Malaysian individuals

Objective: To verify possible relations between 5'-nucleotidase, xanthine oxidase to E3 small ubiquitin-like modifier-protein ligase non structural maintenance of chromosomes elements 2 in sera patients with kidney stones and to evaluate the possibility of a new biomarker for the evaluation of kidney damage. Methods: A sixty patients with known kidney stones who appeared the government health clinics in Kuantan–Pahang and fifty apparently healthy were taken as control group. The 5'-nucleotidase,xanthine oxidase and other biochemical parameters were measured by colorimetric tests. The serum NSMCE2 were measured by enzyme linked immunosorbent assay.Results: The mean serum xanthine oxidase [(39.98±19.70) IU/L] and ecto-5'-nucleotidase activity(40.03±9.53 IU/L) were significantly higher than the controls' levels of(18.04 ±6.26) and(16.06 ±4.61) IU/L respectively. There were 85.00% and 83.33%, of patients with kidney stones who had abnormal ecto-5'-nucleotidase activity and uric acid respectively while xanthine oxidase activity was less sensitive 58.33%.Conclusions: The present study suggests that the increase in serum of xanthine oxidase,ecto-5'-nucleotidase activities E3 small ubiquitin-like modifier-protein ligase NSE2 concentration can be used as biomarkers for diagnosis of kidney damage in patients with kidney stone,also in developments of change DNA damage and inflammation disorders in these patients.

Inhibitory Activity on Xanthine Oxidase and Antioxidant Properties of <i>Teucrium polium</i>

The antioxidative activities of subfractions;methanol (CE), chloroform (CHE) and ethyl acetate (EAE) of Teucrium polium extracts (TPE) were investigated. HPLC analysis of the plant revealed the existence of procyanidins B1 and B2, gallic acid, catechin and epicatechin. All the extracts showed inhibitory properties on xanthine oxidase, with IC50 ranging from 0.80 ± 0.07 to 11.76 ± 0.50 μM/quercetin equivalent. In the cellular system, all the extracts showed a protec-tive effect greater than those of quercetin, rutin and gallic acid against t-BHP induced oxidative damages in human erythrocytes. These results were clearly confirmed by a modified thiobarbituric acid-reactive species (TBARS), and β-carotene/linoleic acid assay which demonstrated that CHE possess an inhibition ratio of the linoleic acid oxidation (83.11%) close to that of BHT (96.77%). In addition, the results showed that the extracts possess a potent DPPH radical scavenging activity and gave a reduction power greater than rutin, quercetin, gallic acid and ascorbic acid in FRAP assay. These results show that Teucrium polium extracts have strong antioxidant effects and may have some clinical benefits.

Correlation of docking energies with spectroscopic kinetic assays of potential xanthine oxidase substrates

Here we present a docking model that ranks compounds according to their potential effectiveness as a potential substrate or inhibitor. We utilize xanthine oxidase (XO), a multi-cofactor oxido-reductase which converts hypoxanthine to xanthine and xanthine to uric acid. During the reductive half reaction, electrons flow from the molybdopterin, to each of two Fe/S centers, and finally to FAD. During the oxidative half reaction, electrons are passed from the FAD to O2. Under ideal physiological conditions, this reduction of oxygen generates H2O2 and, under multiple turnover conditions, superoxide in amounts which is regulated by catalase and superoxide dismutase. Utilizing computer modeling predictions of the docking orientations and energies of a group of purine based structures was selected. Correlating computer estimations with steady state kinetic data, a rapid screening process for inhibittor prediction was highlighted. This method allows educated selection of likely inhibitors, thereby decreasing the time and supplies required to complete a traditional kinetic analysis screening. Results demonstrate the functionality and reliability of this method and have proven particularly useful in understanding binding orienttations or poses of each compound.

<i>In Silico</i>and <i>in Vitro</i>Approach for the Understanding of the Xanthine Oxidase Inhibitory Activity of Uruguayan Tannat Grape Pomace and Propolis Poliphenols

The use of food additives with xanthine oxidase (XO) inhibitory activity offers an alternative approach to hyperuricemic and gout disease treatment, and provides an example of antioxidant nutraceutics. The in vitro and in silico XO inhibitory activity of polyphenols from Uruguayan Tannat grape pomaces and propolis extracts was evaluated as well as the scavenging capacity of said compounds. When comparing propolis and grape pomace samples, the in vitro studies demonstrated that polyphenols extracted from propolis are more active as free radical scavengers than those from Tannat grape pomace. Both natural products effectively inhibited XO but the capacity of phenols present in GP is higher than the one present in P. The high content of anthocyanins in GP, absent in P, could account for this observation. In silico assays allowed us to determine relevant ligand-receptor interactions between polyphenols, from a database built with previously reported polyphenols from both natural products, and the active site of XO. The in silico results showed that compound (E)-isoprenylcaffeate from propolis was the best potential XO inhibitor displaying hydrophobic aromatic interaction between the conjugated ring of the caffeate moiety and polar interactions between hydroxyl groups from caffeate with the active site polar residues. Among grape pomaces, the Cyanidin-3-O-(6-(E)-p-coumaroyl)-glucoside was the best XO inhibitor;its moiety oxychromenyl being relevant to the docking stabilization. All these results lead us to propose Uruguayan propolis and Tannat grape pomace extracts as food additives as well as phytopharmaceuticals to decrease the uric acid levels in gout disease and to act against oxidative stress.

Effect of TongFengNing Decoction on Uric Acid Levels and Xanthine Oxidase Activity in Hyperuricemia Rats

Objective To observe the effect of TongFengNing Decoction （TD） on uric acid levels, xanthine oxidase （XOD） activity, and XOD mRNA expression of hyperuricemia （HUA） model rats. Methods： 90 rats were randomly divided into 6 groups （n=15）, and the HUA model in all groups except the blank group was established by administering hypoxanthine （HX） by gavage and injecting potassium oxonate （OAPS） intraperitoneally. Rats in all TD groups and allopurinol group were administered multiple doses of TD and a single dose of allopurinol by gavage twice daily for 21 days, while the blank group and the model group were administered normal saline. On the 7th, 14th, and 21st days of drug intervention, serum uric acid （SUA）, urine uric acid （UUA）, intestinal uric acid （IUA）, as well as XOD activity and mRNA expression in the liver and small intestine were measured in randomly selected 5 rats of each group. Results： On the 14th and 21st days of intervention, all TD dose groups and the allopurinol group showed decreased SUA and IUA levels, increased UUA levels, as well as decreased XOD activity and mRNA expression in the liver and small intestine, compared with the model group （P 〈 0.05）. The low- and high-dose TD group and the allopurinol group showed increased SUA and IUA levels, as well as XOD activity and mRNA expression in the liver and small intestine, and decreased UUA levels, compared with the moderate-dose TD group （P〈0.05）. Upon extending the drug intervention time of each TD dose group, SUA and IUA levels, XOD activity, and XOD mRNA expression in the liver and small intestine decreased and UUA levels increased （P 〈 0.05）. Conclusion： TD reduces SUA levels in HUA model rats, which promotes uric acid excretion and inhibits XOD activity and XOD mRNA expression to reduce uric acid production. The reduction in uric acid level by the intermediate dose of TD was better than that by allopurinol and the low and high doses of TD.

葛根异黄酮抑制XOD和GLUT9分别发挥减少尿酸生成、促进尿酸排泄双重途径的机制

目的:分析葛根异黄酮抑制XOD和GLUT9分别发挥减少尿酸生成、促进尿酸排泄的可能机制。方法:2021年8月~2022年4月,采用随机数字表法将40只SPF级雄性昆明小鼠分为健康组(1次d频率250 mg/kg剂量灌胃羧甲基纤维素钠)、模型组(HUA小鼠1次d频率250 mg/kg剂量灌胃羧甲基纤维素钠)和低(HUA小鼠1次d频率125 mg/kg剂量灌胃葛根异黄酮)、中(HUA小鼠1次d频率250 mg/kg剂量灌胃葛根异黄酮)、高(HUA小鼠1次d频率500 mg/kg剂量灌胃葛根异黄酮)剂量组,每组各8只。比较各组干预前和干预后(30 d)血清和尿液中尿酸(SUA)、尿素氮(BUN)、肌酐(SCr)含量的统计学差异,比较各组干预后(30 d)肾脏组织中黄嘌呤氧化酶(XOD)和人葡萄糖转运蛋白9(GLUT9)、环氧化酶-2(COX-2)、肿瘤坏死因子(TNF-ɑ)、白细胞介素-1(IL-1β)含量的统计学差异。结果:干预后比较,模型组肾脏炎症因子(COX-2、TNF-ɑ、IL-1β);血液和尿液3项指标(SUA、BUN、SCr);XOD、GLUT9含量均高于健康组(P<0.05);低、中、高剂量组肾脏炎症因子(COX-2、TNF-ɑ、IL-1β);血液和尿液3项指标(SUA、BUN、SCr);XOD、GLUT9含量均低于模型组,且有低>中>高剂量组,两两分组的比较均有统计学意义(P<0.05)。干预后相比干预前,血液或尿液3项指标(COX-2、TNF-ɑ、IL-1β)含量均有下降,组内比较的差异均有统计学意义(P<0.05)。结论:葛根异黄酮能治疗HUA小鼠能通过抑制XOD、GLUT9表达,继而发挥减少尿酸生成、促进尿酸排泄作用,同时有利于缓解疾病的炎症程度。

Inhibition of xanthine oxidase alleviated pancreatic necrosis via HIF-1α-regulated LDHA and NLRP3 signaling pathway in acute pancreatitis

Acute pancreatitis(AP)is a potentially fatal condition with no targeted treatment options.Although inhibiting xanthine oxidase(XO)in the treatment of AP has been studied in several experimental models and clinical trials,whether XO is a target of AP and what its the main mechanism of action is remains unclear.Here,we aimed to re-evaluate whether XO is a target aggravating AP other than merely generating reactive oxygen species that trigger AP.We first revealed that XO expression and enzyme activity were significantly elevated in the serum and pancreas of necrotizing AP models.We also found that allopurinol and febuxostat,as purine-like and non-purine XO inhibitors,respectively,exhibited protective effects against pancreatic acinar cell death in vitro and pancreatic damage in vivo at different doses and treatment time points.Moreover,we observed that conditional Xdh overexpression aggravated pancreatic necrosis and severity.Further mechanism analysis showed that XO inhibition restored the hypoxia-inducible factor 1-alpha(HIF-1α)-regulated lactate dehydrogenase A(LDHA)and NOD-like receptor family pyrin domain containing 3(NLRP3)signaling pathways and reduced the enrichment of^(13)C_(6)-glucose to^(13)C_(3)-lactate.Lastly,we observed that clinical circulatory XO activity was significantly elevated in severe cases and correlated with C-reactive protein levels,while pancreatic XO and urate were also increased in severe AP patients.These results together indicated that proper inhibition of XO might be a promising therapeutic strategy for alleviating pancreatic necrosis and preventing progression of severe AP by downregulating HIF-1α-mediated LDHA and NLRP3 signaling pathways.

Pueraria isoflavones inhibit XOD and GLUT9 to decrease uric acid production and promote uric acid excretion, respectively

Objective: To analyze the possible mechanism of Pueraria isoflavones inhibiting XOD and GLUT9 to reduce uric acid production and promote uric acid excretion. Methods: August 2021-April 2022, a total of forty SPF male Kunming mice were divided into the healthy group (carboxymethylcellulose sodium at a dose of 250 mg/kg), the model group (HUA mice were given carboxymethylcellulose sodium at a dose of 250 mg/kg), the low group (HUA mice were given pueraria isoflavone at a dose of 125 mg/kg), HUA mice were given pueraria isoflavones at a dose of 250 mg/kg once d frequency)and the high group (HUA mice were given pueraria isoflavones at a dose of 500 mg/kg once d frequency) dosage groups, with 8 mice in each group. The contents of uric acid (SUA), urea nitrogen (BUN) and creatinine (SCr) in serum and urine of each group were compared before and after intervention (30 d). Statistical differences of xanthine oxidase (XOD) and human glucose transporter 9(GLUT9), cy- clooxygenase- 2(COX-2), tumor necrosis factor (TNF-α) and interleukin-1 (IL-1β) contents in renal tissues of each group after intervention (30 d) were compared. Results: After intervention, kidney inflammatory factors (COX-2, TNF-α and IL-1β) in the model group were compared. Blood and urine indexes (SUA, BUN, SCr);The contents of XOD and GLUT9 were higher than those of healthy group(P<0.05). Renal inflammatory cytokines (COX-2, TNF-α and IL-1β) in low, medium and high dose groups;Blood and urine indexes (SUA, BUN, SCr);The contents of XOD and GLUT9 were lower than those of model group, and there were low > medium > high dose groups, the comparison between the two groups had statistical significance(P< 0.05). After intervention, the contents of 3 indicators in blood or urine(COX-2, TNF-α and IL-1β) all decreased compared with before intervention, and the differences in intra-group comparison were statistically significant (P<0.05). Conclusion: Pueraria isoflavones can treat HUA mice by inhibiting the expression of XOD and GLUT9, and then play a role in reducing uric acid pro- duction and promoting uric acid excretion, as well as alleviating the degree of disease inflammation.

Purification and Characterisation of Xanthine Oxidoreductases from Local Bovids in Malta

Xanthine oxidoreductase (XOR) is a molybdoflavoprotein mainly involved in purine catabolism. It exists in two forms, the oxidase (XO) and dehydrogenase (XDH) which are inter-convertible within mammalian cells. Although various researchers have reported the extraction of mammalian XOR, no extractions have yet been carried out in Malta and subsequently no characterizations are available. In this study, XOR was successfully purified from bovine, caprine and ovine milk through a multistep purification process involving both chemical and chromatographic techniques. The molecular weights of the native enzyme were found to be 295 kDa, 281 kDa and 275 kDa, representing the bovine, caprine and ovine XOR respectively. Western blot showed XOR to be represented on SDS-PAGE by a minimum of three major bands having molecular weights of 151 kDa, 131 kDa and 85 kDa. While all samples showed activity on native PAGE, spectrophotometric assays revealed the bovine XOR to be the most active. Surprisingly, the addition of NAD+ to the assay mixture inhibited enzyme activity of the bovine and caprine XOR whereas the ovine XOR doubled its activity in response to NAD+. The latter also showed a lower binding affinity to heparin. Following incubation with trypsin, XOR was irreversibly converted to its oxidase form in all samples as reflected by the observed increase in XO activity.

Oxidase Enzyme Activities and Their Correlations with Antioxidative Stress Biomarkers in Patients with Acute Coronary Syndrome in Bangladesh

Acute coronary syndrome (ACS) is a range of conditions associated with decreased blood flow in the coronary arteries resulting from sudden rupture of atherosclerotic plaques. Several studies have found that oxidative stress is involved in the initiation and progression of atherosclerosis. The role of oxidase enzymes and antioxidative stress biomarkers in these processes needs further attention. In this study, a total of 120 participants were enrolled which comprised 60 ACS patients and 60 control subjects. The major oxidase enzyme, xanthine oxidase, which plays a pivotal role in the generation of reactive oxygen species (ROS), showed significantly higher activities in both serum (158.03 ± 43.30 mU/mL) and red blood cells (RBC) lysate (309.07 ± 75.73 mU/mL) of the ACS patients compared to controls, 48.51 ± 13.41 mU/mL and 184.10 ± 70.14 mU/mL, respectively. The nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and myeloperoxidase, both of which are major contributors to ROS production, showed significantly higher activities in patients (14.13 ± 3.38 U/L and 10.9 ± 3.3 U/mg) than in controls, 6.90 ± 1.94 U/L and 5.9 ± 1.5 U/mg, respectively. Ceruloplasmin, an emerging biomarker of inflammation, showed significantly higher activity in patients (83.8 ± 26.2 U/L) compared to controls, 70.0 ± 18.9 U/L. The antioxidant enzyme glutathione reductase showed significantly lower activity in patients than controls, 60.7 ± 47.8 U/mL/min and 85.2 ± 49.5 U/mL/min, respectively. Evaluation of cardioprotective biomarkers nitric oxide and high-density lipoprotein-cholesterol (HDL-C) showed significantly lower values in patients. Correlation analyses between these parameters further corroborated increased oxidative stress in patients. These findings suggest that excessive productions of ROS by the oxidase enzymes cause an imbalance between oxidants and antioxidants in favor of oxidants leading to increased oxidative stress in patients with ACS.

柴胡皂苷D对高尿酸血症大鼠尿酸及相关酶活性的影响

目的:探讨柴胡皂苷D对高尿酸血症大鼠体内尿酸水平及相关酶活性的影响。方法:柴胡皂苷D用0.9%氯化钠溶液溶解,配制成5、10、20 mg/mL药液。将50只SD大鼠随机分为对照组、模型组及柴胡皂苷D大、中、小剂量组。除对照组外,其余大鼠每天上午灌胃腺嘌呤0.2 g/kg+乙胺丁醇0.25 g/kg,建立高尿酸血症模型。柴胡皂苷D各剂量组大鼠均以10 mL/kg的剂量灌胃给药,对照组大鼠与模型组大鼠灌胃同等剂量0.9%氯化钠溶液。检测给药前、给药后14、21、28 d大鼠血尿酸、尿尿酸以及黄嘌呤氧化酶(XOD)、腺苷脱氨酶(ADA)、肌酐和尿素氮的水平。结果:给药后21 d,与对照组比较,模型组大鼠血尿酸水平明显升高;与模型组相比,柴胡皂苷D中剂量组血尿酸水平显著下降,差异均具有统计学意义(P<0.05);给药后28 d,与模型组相比,柴胡皂苷D大剂量组、中剂量组血尿酸水平显著下降,中剂量组及小剂量组大鼠尿尿酸水平显著降低;柴胡皂苷D各剂量组大鼠的ADA、XOD、肌酐及尿素氮水平均显著下降,差异均具有统计学意义(P<0.05)。结论:柴胡皂苷D可以通过降低ADA以及XOD水平,抑制尿酸生成,起到降尿酸的作用,具有显著的肾脏保护功能。

新型大黄酸-牛磺酸化合物的合成、表征及其抑制黄嘌呤氧化酶的活性研究

大黄酸(Rhein,RH)可以促进尿酸肠道排泄,改善肾脏损伤,降低血清尿酸水平。牛磺酸(Taurine,T)可以修复肾脏损伤,降低黄嘌呤氧化酶(Xanthine oxidase,XOD)活力,还可降低血清尿酸水平。因此两种化合物在降尿酸、改善肾损伤方面具有相似的药理活性。通过拼合原理,将RH和T通过酰胺键连接,合成大黄酸-牛磺酸化合物(T-RH),以期发挥协同增效作用。采用^(1)H NMR、^(13)C NMR、IR和MS(ESI)对T-RH化学结构进行表征,并考察了T-RH对体外XOD的抑制作用。结果表明:T-RH被成功合成,产率为65.73%。T-RH对体外XOD的抑制作用均显著优于大黄酸(^(**)P<0.01)和牛磺酸(^(##)P<0.01),且抑制活性与T-RH的浓度呈正相关。

龙胆苦苷对果糖诱导小鼠高尿酸血症的作用

目的:研究龙胆苦苷对果糖诱导小鼠高尿酸血症的治疗作用。方法:昆明种小鼠连续饮用10%果糖溶液12周以制备高尿酸症小鼠模型,从第9周开始,别嘌呤醇组,龙胆苦苷高、中、低剂量组(80 mg/kg、40 mg/kg、20 mg/kg-)每天灌胃给药1次,共给药4周。末次给药后取血,检测血清谷丙转氨酶(GPT)、谷草转氨酶(GOT)、尿酸(UA)、肌酐(Cr)和血尿素氮(BUN)水平,苏木精-伊红(HE)染色观察肝、肾组织的变化;酶联免疫吸附试验法检测肾组织中超氧化物歧化酶(SOD),丙二醛(MDA),肿瘤坏死因子α(TNF-α)和白细胞介素-6(IL-6)水平,比色法和蛋白质免疫印迹法检测肝组织中黄嘌呤氧化酶(XOD)活性及蛋白表达水平。结果:与模型组比较,龙胆苦苷各给药组小鼠血清GPT、GOT、UA、Cra和BUN水平显著降低(P<0.01),肝、肾病理学变化有所改善;肾脏SOD水平显著升高(P<0.01),MDA、TNF-α和IL-6水平显著降低(P<0.01);同时肝脏XOD的活性及蛋白表达水平显著下调(P<0.01或P<0.05)。结论:龙胆苦苷通过降低XOD活性和表达,降低尿酸水平,进而减轻肾脏氧化应激和炎症水平,达到肾脏保护作用。

桑黄游离酚提取物体外降尿酸活性研究

为研究桑黄游离酚提取物体外降尿酸活性,以野生瓦宁木层孔菌、栽培粗毛纤孔菌、栽培瓦宁木层孔菌和野生粗毛纤孔菌4个不同来源的桑黄为研究对象,分析不同来源桑黄游离酚提取物对黄嘌呤氧化酶的抑制活性,及其在高尿酸细胞模型中的降尿酸作用。筛选出降尿酸活性强的桑黄游离酚提取物,并通过超高效液相色谱-串联质谱(ultra performance liquid chromatography/tandem mass spectrometry,UPLC-MS/MS)对其降尿酸活性物质进行分析。研究结果表明,栽培粗毛纤孔菌、栽培瓦宁木层孔菌和野生粗毛纤孔菌的游离酚提取物对黄嘌呤氧化酶具有显著的抑制作用(P<0.05),IC_(50)值分别为(94.63±2.73)μg/mL、(99.69±2.50)μg/mL和(106.32±5.06)μg/mL;栽培粗毛纤孔菌和野生瓦宁木层孔菌的游离酚提取物可显著抑制高尿酸细胞模型中尿酸生成(P<0.05)。进一步通过UPLC-MS/MS分析活性较强的栽培粗毛纤孔菌游离酚中主要成分发现,其黄酮类物质中金丝桃苷、表儿茶素、茶黄素、地奥司明及木犀草苷等,可能是其降尿酸的主要活性物质。该研究可为桑黄降尿酸产品的研究与开发提供部分理论参考。