Objective:To investigate the effects of a crude extract from Gnetum montanum Markgr.on ethanol-induced hepatotoxicity and metabolic disorders.Methods:Alcoholic liver disorder was induced in mice by administering incre...Objective:To investigate the effects of a crude extract from Gnetum montanum Markgr.on ethanol-induced hepatotoxicity and metabolic disorders.Methods:Alcoholic liver disorder was induced in mice by administering increasing doses of ethanol via oral gavage.Biomarkers of liver injury and oxidative stress were assessed at the end of the study.Liver tissue damage and fat deposition were evaluated using hematoxylin and eosin and oil red O staining,respectively.In addition,key biomarkers were examined in acetaldehyde-treated HepG2 cells.Results:Ethanol consumption induced characteristic pathological changes,including elevated serum markers of liver injury,hepatic lipid accumulation,and oxidative stress in liver tissues.Oral administration of Gnetum montanum extract(175 and 350 mg/kg)decreased serum aspartate aminotransferase,alanine aminotransferase,γ-glutamyl transferase,and bilirubin levels in ethanol-treated mice.The extract also lowered triglyceride levels in serum and liver tissue in a dose-dependent manner.Furthermore,it mitigated malondialdehyde levels,preserved reduced glutathione levels,and enhanced catalase activity and total antioxidant capacity in liver tissue homogenates.Additionally,ethanol-induced hyperuricemia was suppressed by Gnetum montanum extract by inhibiting xanthine oxidase activity.Similar effects were observed in Gnetum montanum extract-treated HepG2 cells.Conclusions:This study demonstrates that Gnetum montanum extract alleviates ethanol-induced hepatic injury by alleviating oxidative stress and inhibiting xanthine oxidase activity.展开更多
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 ac...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.展开更多
OBJECTIVE: To investigate the effects of needling the Shu, Yuan, and Mu acupoints on serum uric acid(SUA), xanthine oxidase(XOD), and alkaline phosphatase(ALP) levels and the kidney index in a rat model of gout and hy...OBJECTIVE: To investigate the effects of needling the Shu, Yuan, and Mu acupoints on serum uric acid(SUA), xanthine oxidase(XOD), and alkaline phosphatase(ALP) levels and the kidney index in a rat model of gout and hyperuricemia.METHODS: Fifty rats were randomly divided into five groups: blank, model, Shu-acupoint, Yuan-acupoint, and Mu-acupoint groups. A rat model of hyperuricemia was developed by intragastric administration of adenine and ethambutol. This experiment last for 90 d in total. Treatment groups underwent 3 courses of acupuncture. Each course involved a total of 10 interventions(one intervention every second day) with each intervention lasting15 min. There was a break for 10 d between courses. SUA and ALP were analyzed using an automatic biochemical analyzer and XOD was analyzed using immunofluorescence.RESULTS: Compared with the blank group, SUA and XOD levels in the model group were significantly higher and the renal index significantly improved. Compared with the model group, SUA and XOD levels in the three treatment groups decreased and the renal index significantly improved.When the three treatment groups were compared,the Mu-acupoint group showed the greatest decreases in SUA and XOD levels, followed by the Yuan-acupoint group. There was no significant difference in kidney index among the three treatment groups. There was no significant difference in ALP levels among the groups.CONCLUSION: The three treatments showed significantly reduced SUA and XOD levels compared with the control groups, possibly suggesting reduced renal damage.展开更多
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 t...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.展开更多
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 a...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.展开更多
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 ...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.展开更多
Snow chrysanthemum,the capitulum of Coreopsis tinctoria Nutt.,was found to possess inhibitory activity on xanthine oxidase(XO),one of the key enzymes in the pathogenesis of gout.Assisted by bioactivity-oriented isolat...Snow chrysanthemum,the capitulum of Coreopsis tinctoria Nutt.,was found to possess inhibitory activity on xanthine oxidase(XO),one of the key enzymes in the pathogenesis of gout.Assisted by bioactivity-oriented isolation,a total of 16 compounds containing a new compound were obtained from the active fractions of snow chrysanthemum extract,including two aurones(1,2),four chalcones(3-6),a flavone(7),four flavonols(8-11),a flavanonol(12),three phenylpropanoids(13-15),and a new polyacetylene glycoside(16).All the isolated compounds were assayed for their inhibitory activity on XO,among which eight polyphenols(1-8)exhibited potent or moderate inhibitory activities with IC_(50) values from 0.65 to 29.11μM.The structure-activity relationship was interpreted for polyphenols(1-12).Besides,the inhibition properties of compounds 1-4 against XO were comprehensively investigated through enzyme kinetics,fluorescence quenching,and docking simula-tion.Maritimetin(1)and sulfurein(2)reversibly inhibited XO by mixed type mechanism.Okanin-4′-O-(6″-acetyl)-β-D-glucopyranoside(3)and coreopsin(4)competitively inhibited XO in reversible and irreversible manners,respectively.In addition,fluorescence quenching studies suggested that all four compounds interacted with XO through a static quenching mechanism.Molecular docking inferred that hydrogen bonds and hydro-phobic interaction played key roles in the binding process.This study revealed the XO-inhibitory activity of snow chrysanthemum and the contribution of containing aurones and chalcones to XO inhibition,making it a potential functional food ingredient for management of hyperuricemia.展开更多
Post-translational modifications(PTMs)by disulfide-bond formation and limited proteolysis are well-established to transform some xanthine dehydrogenase(XDH)to xanthine oxidase(XOD),which utilize NAD and oxygen as resp...Post-translational modifications(PTMs)by disulfide-bond formation and limited proteolysis are well-established to transform some xanthine dehydrogenase(XDH)to xanthine oxidase(XOD),which utilize NAD and oxygen as respective functionally equivalent electron acceptors,but the uncontrollability of PTMs challenges the efficient production of active XOD,and do not work for other post-translationally non-convertible pure XDHs.To overcome these limitations,this study aimed to rationally engineer the electron acceptor region of XDH to enable one-step synthesis of functional XOD without relying on PTMs.A proof-of-concept study of PTM-independent one-step synthesized XOD was initiated by rationally engineering the electron acceptor region of XDH here.Five mutants of Rhodobacter capsulatus XDH increased the catalytic activity with O_(2) as electron acceptor by up to 2124-times to commercial XODs’level.Structurally equivalent mutations of Acinetobacter baumannii XDH(AbXDH)switched it from a post-translationally non-convertible pure XDH to virtual XODs with the best turnover number and catalytic efficiency of 85.17 s^(-1)and 126.15μM^(-1) s^(-1)using O_(2) as electron acceptor,which was 45-times higher than the wild-type AbXDH utilizing NAD,outperforming commercially available XODs.The present success of electron acceptor switch by rationally refactoring the electron acceptor region of the electron transfer chain,especially engineering of the NAD-binding loop has also implicated its potential utility in other oxidoreductases as a new tool for cofactor engineering.展开更多
In this article,quantum mechanical/molecular mechanical(QM/MM)methods were used to study the full catalytic mechanism of xanthine oxidase(XO).XO catalyzes the conversion of xanthine(XAN)to uric acid(URC),in the presen...In this article,quantum mechanical/molecular mechanical(QM/MM)methods were used to study the full catalytic mechanism of xanthine oxidase(XO).XO catalyzes the conversion of xanthine(XAN)to uric acid(URC),in the presence of a molybdenum cofactor(Moco).The mechanism occurs through four reaction steps.Initially,the proton from the hydroxyl group of Moco passes to Glu1261 and the activated hydroxyl group makes a nucleophilic attack on XAN.Then,a hydride is transferred from the tetrahedral intermediate to the sulfur atom of the Moco,reducing Mo(Ⅵ)to Mo(Ⅳ).In the third step,one molecule of URC is formed through its protonation by Arg880.Once this reaction is complete,FAD is reduced to FADH_(2),oxidizing Mo(Ⅳ)to its initial oxidation state of Mo(Ⅵ).The enzymatic turnover is achieved with the reaction of one water molecule with the Moco.The rate-limiting step of the full catalytic mechanism is the hydride transfer that requires a free activation barrier of 16.9 kcal mol^(−1),which closely agrees with the experimental kcat value(18.3 s^(−1)),which corresponds to approximately 15.7 kcal mol^(−1).This work also elucidates the key role played by Arg880 in the catalytic mechanism and the importance of Glu802 in the binding of the substrate.Both residues were previously shown to be important by mutagenesis studies,but their role was still not clearly understood.Additionally,it was observed that the presence of a tunnel of water molecules located close to Moco and Glu1261 is important for the enzymatic turnover.The determined transition state structures can now be used to help the development of transition-state analog inhibitors targeting XO.展开更多
Current treatment of hyperuricemia relies on xanthine oxidase(XO)inhibitors that block uric acid production.This study investigated two fish maw(FM)types,from miiuy croaker and silver carp,as novel sources of peptides...Current treatment of hyperuricemia relies on xanthine oxidase(XO)inhibitors that block uric acid production.This study investigated two fish maw(FM)types,from miiuy croaker and silver carp,as novel sources of peptides with XO inhibition(XOI)benefit.Alcalase 2L was the most effective protease to hydrolyze the FM.Hydrolysates from freshwater FM exhibited stronger XOI activity than hydrolysates from medicinal FM,with XOI activity of 80.33%±1.64%and 65.94%±0.08%,respectively,and IC_(50)of 9.08±0.24 mg/mL and 11.23±0.31 mg/mL,respectively.In silico screening and molecular docking simulations identified four candidate peptides,EFF and DSLGF from freshwater FM,and EQGF and PSGPQ from medicinal FM,with the highest binding affinity to the XO receptor.The binding primarily consisted of hydrogen bonds,hydrophobic interactions and cation interactions.Phe residues on peptide sequences were key contributors to XO-peptide interactions.This was further validated by DFT quantum calculations.Phenyl rings on F-3(EFF),F-5(DSLGF)and the carbonyl group of E-1(EQGF),and Q-5(PSGPQ)were identified as key reactive sites by DFT calculations.When tested in vitro,the XOI of the four peptides decreased in the order:EFF(47.54%±0.19%)>EQGF(40.13%±0.86%)>DSLGF(34.91%±0.55%)>PSGPQ(34.84%±0.12%).These findings suggest that both low-value silver carp FM and medicinal miiuy croaker FM are potential source of peptides with anti-hyperuricemia functions.Moreover,combining computational tools like molecular docking simulations and DFT could be effective in elucidating peptide-receptor target interactions and structure-activity relationships.展开更多
In this study,two novel xanthine oxidase inhibitory peptides,PDEAVAYG(820.3602 Da)and IAAGLQNTG(843.4450 Da),were purified and identified from tea protein hydrolysate,and their IC_(50) values were 0.09 mg/mL(109.71μM...In this study,two novel xanthine oxidase inhibitory peptides,PDEAVAYG(820.3602 Da)and IAAGLQNTG(843.4450 Da),were purified and identified from tea protein hydrolysate,and their IC_(50) values were 0.09 mg/mL(109.71μM)and 0.24 mg/mL(284.55μM),respectively.During the gastrointestinal simulation digestion,PDEAVAYG was broken down into new peptides,while IAAGLQNTG exhibited some stability.Molecular docking results showed that hydrogen bonding,π-πstacking,and hydrophobic interactions exerted crucial effects on the interaction between peptides and xanthine oxidase.In the hyperuricemia cell model,compared to the model group,1.0 mg/mL of PDEAVAYG and IAAGLQNTG decreased cellular uric acid levels by 40.80%and 33.33%,respectively.The RNA-seq experiments revealed that PDEAVAYG could alleviate hyperuricemia by regulating mRNA expression for pro-inflammatory factors,growth factors associated with cardiovascular disease,and uric acid efflux transporter proteins in cells.This study provides a new theoretical reference for the development of functional foods or nutritional supplements using peptides with anti-hyperuricemic activity.展开更多
This study systematically investigates the structure-activity relationship and xanthine oxidase(XO)inhibitory potential of Ferulic acid oligomers(FAOs)through DFT calculations and molecular docking.The BDE and IP valu...This study systematically investigates the structure-activity relationship and xanthine oxidase(XO)inhibitory potential of Ferulic acid oligomers(FAOs)through DFT calculations and molecular docking.The BDE and IP values exhibit a parabolic trend from dimer to hexamer configurations,with the ferulic acid tetrameric form demonstrating optimal radical scavenging capacity.Solvent-phase analyses reveal that SPLET and SETPT mechanisms require lower activation energies in three environments compared with vacuum conditions.Moreover,HAT is the primary antioxidant pathway of FAOs.Molecular docking identifies TeFA5-8-8-5 and TeFA2-2-3-3 as dual-functional therapeutic candidates that exhibit potent antioxidant activity and XO inhibition through optimized hydrogen bonding and hydrophobic interactions.TeFA5-8-8-5 and TeFA2-2-3-3 can serve as dual-functional candidate agents for natural antioxidants and XO inhibitors.HLg and molecular orbitals can prove their stability and antioxidant mechanism.Therefore,TeFA can not only meet the industrial demand for ideal antioxidants but can also be developed into more effective gout drugs.展开更多
The development of natural xanthine oxidase(XO)inhibitors is an effective strategy for the treatment of hy-peruricemia.In this study,the inhibition mechanism of phloretin on XO and its joint inhibition with clinical d...The development of natural xanthine oxidase(XO)inhibitors is an effective strategy for the treatment of hy-peruricemia.In this study,the inhibition mechanism of phloretin on XO and its joint inhibition with clinical drugs(allopurinol and febuxostat)were investigated,using multispectroscopic and molecular simulation tech-niques.The results showed that phloretin reversibly inhibited XO in a mixed type with an IC_(50) value of 31.83±0.32μM.Phloretin quenched the fluorescence of XO with a static mechanism and hydrophobic interactions were the key binding force of phloretin binding to XO.Furthermore,the interaction between phloretin and XO resulted in a more relaxed structure and less stable of the enzyme with a reduction in theα-helix content from 21.5%to 11.3%.The heatmap analysis showed that a combination of phloretin(15μM)and allopurinol(10μM)or phloretin(30μM)and febuxostat(0.01μM)exhibited the strongest synergistic effect on XO inhibition in a mixed manner.The combination of phloretin and allopurinol/febuxostat enhanced the binding affinity with XO compared to the inhibitors individually.Molecular docking indicated that phloretin,allopurinol and febuxostat bound to different sites of XO to produce a synergistic inhibition by preventing substrate access to the Mo activity center and affecting electron transfer.This study may provide theoretical references for the development of phloretin and its formulation with clinical drugs as uric acid-lowering food functional factor or drug.展开更多
Inhibition of xanthine oxidase(XO)activity is an effective strategy for the treatment of hyperuricemia and gout.However,some nutrients(such as lipids,proteins,and vitamins,etc)in the daily diet may affect the binding ...Inhibition of xanthine oxidase(XO)activity is an effective strategy for the treatment of hyperuricemia and gout.However,some nutrients(such as lipids,proteins,and vitamins,etc)in the daily diet may affect the binding of enzyme inhibitors to XO.The effects of three unsaturated fatty acids(USFAs,namely oleic acid,linoleic acid andα-linolenic acid)on the inhibition of XO by phloretin were investigated in the study.The results showed that USFAs significantly enhanced the inhibitory effect of phloretin on XO,primarily due to the changes in secondary structure and increased binding affinity.The order of enhancement wasα-linolenic acid>oleic acid>linoleic acid.The USFAs synergistically destroyed the hydrogen bond network structure of XO with phloretin,resulting in a looser and more disordered XO structure.Moreover,phloretin formed more hydrogen bonds,hydrophobic interactions and van der Waals forces with the amino acid residues of XO in the presence of USFAs,which eventually increased the inhibitory ability of phloretin on XO.The study may provide a new perspective for the dietary nutrition intervention of the patients with hyperuricemia and gout.展开更多
A mangiferin aglycon derivative J99745 has been identified as a potent xanthine oxidase(XOD) inhibitor by previous in vitro study. This study aimed to evaluate the hypouricemic effects of J99745 in experimental hyperu...A mangiferin aglycon derivative J99745 has been identified as a potent xanthine oxidase(XOD) inhibitor by previous in vitro study. This study aimed to evaluate the hypouricemic effects of J99745 in experimental hyperuricemia mice, and explore the underlying mechanisms. Mice were orally administered 600 mg/kg xanthine once daily for 7 days and intraperitoneally injected 250 mg/kg oxonic acid on the 7 th day to induce hyperuricemia. Meanwhile, J99745(3, 10, and 30 mg/kg), allopurinol(20 mg/kg) or benzbromarone(20 mg/kg) were orally administered to mice for 7 days. On the 7 th day,uric acid and creatinine in serum and urine, blood urea nitrogen(BUN), malondialdehyde(MDA) content and XOD activities in serum and liver were determined. Morphological changes in kidney were observed using hematoxylin and eosin(H&E) staining. Hepatic XOD, renal urate transporter 1(URAT1), glucose transporter type 9(GLUT9), organic anion transporter 1(OAT1) and ATP-binding cassette transporter G2(ABCG2) were detected by Western blot and real time polymerase chain reaction(PCR). The results showed that J99745 at doses of 10 and 30 mg/kg significantly reduced serum urate, and enhanced fractional excretion of uric acid(FEUA). H&E staining confirmed that J99745 provided greater nephroprotective effects than allopurinol and benzbromarone. Moreover, serum and hepatic XOD activities and renal URAT1 expression declined in J99745-treated hyperuricemia mice. In consistence with the ability to inhibit XOD, J99745 lowered serum MDA content in hyperuricemia mice. Our resultssuggest that J99745 exerts urate-lowering effect by inhibiting XOD activity and URAT1 expression, thus representing a promising candidate as an anti-hyperuricemia agent.展开更多
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 tri...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.展开更多
Flos Sophorae Immaturus (FSI) possessed potential xanthine oxidase (XO) inhibitory activity as a uric acid-lowing natural product.The present work identified and quantified the free and bound polyphenols of FSI by UPL...Flos Sophorae Immaturus (FSI) possessed potential xanthine oxidase (XO) inhibitory activity as a uric acid-lowing natural product.The present work identified and quantified the free and bound polyphenols of FSI by UPLC-QTOF-MS.Then determined the primary polyphenols with XO inhibitory effect and clarified their potential mechanisms by omission experiment,interaction assay,inhibition type,and fluorescence measurements.The results revealed that nine polyphenols were detected in the free polyphenol extract and ten polyphenols were detected in the bound polyphenol extract.Meanwhile,seven polyphenols were identified as XO inhibitors,including quercetin,kaempferol,isorhamnetin,rutin,hyperoside,protocatechuic acid,and quercitrin with the IC50 values of 0.03,0.11,0.07,5.62,11.48,22.13,and 367.82 mg/mL,but their inhibition stability was lower than 24 h.Although the content of quercetin (18.87 mg/g) was not the highest,it played a crucial role to the XO inhibitory effect of FSI.Furthermore,kaempferol and isorhamnetin alone revealed the sub-additive effect with quercetin,while the combination of other polyphenols with quercetin generated the interference or antagonism effects.Quercetin,isorhamnetin,and kaempferol were mixed-type and competitive inhibitors,which significantly quenched the fluorescence intensity of XO.Moreover,the binding processes of quercetin-XO,kaempferol-XO,and isorhamnetin-XO were spontaneous and endothermic,and the hydrophobic interaction was the key driving force.In general,quercetin,kaempferol,and isorhamnetin in FSI can be used as potential XO inhibitors.展开更多
Gout, as the second major metabolic disease after cardiovascular disease. Peptides have the advantages of natural and no side effects in the treatment and prevention of gout. This study aimed to screen xanthine oxidas...Gout, as the second major metabolic disease after cardiovascular disease. Peptides have the advantages of natural and no side effects in the treatment and prevention of gout. This study aimed to screen xanthine oxidase (XOD) inhibitory peptides from Scophthalmus maximus protein as a drug basis for the treatment of gout. The specific results are as follows: Immobilization of xanthine oxidase 25.564 μg/mg by modified magnetic beads, and modified magnetic beads can be reused three times. Three decapeptides (FSLVHYAGTV, FTNEKLQQFF and WDDMEKIWHH) were screened, the IC_(50) were 3.741, 4.046 and 2.203 mg/mL. Circular dichroism and three-dimensional fluorescence spectra showed that the inhibitory peptide would change the helical structure of XOD and the internal hydrophobic environment. Molecular docking showed that the inhibitory effect of inhibitory peptides depends on the number of unique amino acid residues in the active center of XOD enzyme. In conclusion, this study provides a method for screening anti-gout peptides, which not only solves the problem of treating gout, but also realizes the high-value utilization of marine products. In addition, this method has substantial application value because of its low cost and simple operation.展开更多
Objectives:This study was conducted to investigate the xanthine oxidase(XO)inhibitory activities of 18 monomeric anthocyanins from berry fruits and roselle,and to illustrate the underlying mechanism of the most active...Objectives:This study was conducted to investigate the xanthine oxidase(XO)inhibitory activities of 18 monomeric anthocyanins from berry fruits and roselle,and to illustrate the underlying mechanism of the most active anthocyanin delphinidin-3-O-sambubioside.Materials and Methods:Eighteen monomeric anthocyanins were prepared and purified in our laboratory.The inhibitory properties of anthocyanins were investigated by in vitro inhibitory activity studies and fluorescence quenching studies;the inhibitory mechanism was explored through kinetic studies,fluorescence quenching studies,circular dichroism analysis and computational docking simulations.Results:XO inhibitory activities of anthocyanins were related to the structures of B rings and glycosides.Among all the tested anthocyanins,delphinidin-3-O-sambubioside showed the most potent inhibitory activity with an IC_(50) of 17.1μmol/L,which was comparable to the positive control allopurinol.Spectroscopic results revealed that delphinidin-3-O-sambubioside could spontaneously interact with XO and induce conformational changes.Computational docking study indicated that delphinidin-3-O-sambubioside could bind to XO with a proper orientation,stably formed π-π interactions and hydrogen bonds with key residues,thus preventing the substrate from entering the active pocket.Conclusions:In brief,our study identified delphinidin-3-O-sambubioside as a potent XO inhibitor from natural anthocyanins,which is potentially applicable for prevention and treatment of hyperuricemia.展开更多
Heart failure is currently one of the most common and most cost-intensive of the chronic diseases The main cause of chronic heart failure （CHF） is the abnormalities of both cardiac contractile performance and myocar...Heart failure is currently one of the most common and most cost-intensive of the chronic diseases The main cause of chronic heart failure （CHF） is the abnormalities of both cardiac contractile performance and myocardial energy metabolism. Elevated levels of reactive oxygen species （ROS） have been proposed to contribute to both of them. Xanthine oxidoreductase （XO） is a major source of ROS in the cardiovascular system. XO inhibitors （XOIs） have been the cornerstone of the clinical management of gout and conditions associated with hyperuricemia for several decades.展开更多
基金funded by Vietnam National Foundation for Science and Technology Development under grant number 108.05-2023.23.
文摘Objective:To investigate the effects of a crude extract from Gnetum montanum Markgr.on ethanol-induced hepatotoxicity and metabolic disorders.Methods:Alcoholic liver disorder was induced in mice by administering increasing doses of ethanol via oral gavage.Biomarkers of liver injury and oxidative stress were assessed at the end of the study.Liver tissue damage and fat deposition were evaluated using hematoxylin and eosin and oil red O staining,respectively.In addition,key biomarkers were examined in acetaldehyde-treated HepG2 cells.Results:Ethanol consumption induced characteristic pathological changes,including elevated serum markers of liver injury,hepatic lipid accumulation,and oxidative stress in liver tissues.Oral administration of Gnetum montanum extract(175 and 350 mg/kg)decreased serum aspartate aminotransferase,alanine aminotransferase,γ-glutamyl transferase,and bilirubin levels in ethanol-treated mice.The extract also lowered triglyceride levels in serum and liver tissue in a dose-dependent manner.Furthermore,it mitigated malondialdehyde levels,preserved reduced glutathione levels,and enhanced catalase activity and total antioxidant capacity in liver tissue homogenates.Additionally,ethanol-induced hyperuricemia was suppressed by Gnetum montanum extract by inhibiting xanthine oxidase activity.Similar effects were observed in Gnetum montanum extract-treated HepG2 cells.Conclusions:This study demonstrates that Gnetum montanum extract alleviates ethanol-induced hepatic injury by alleviating oxidative stress and inhibiting xanthine oxidase activity.
基金funded by Vietnam National Foundation for Science and Technology Development(NAFOSTED)under grant number 106.99-2012.90
文摘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.
基金Supported by Central Universities Fundamental Research Funds Project(Graduate Programs)from the Beijing University of Chinese Medicine:Experiment Research on the Effects of Acupuncturing Shu,Yuan,and Mu Acupoints in a Rat Model of Gout and Hyperuricemia(No.2015-JYB-XS127)
文摘OBJECTIVE: To investigate the effects of needling the Shu, Yuan, and Mu acupoints on serum uric acid(SUA), xanthine oxidase(XOD), and alkaline phosphatase(ALP) levels and the kidney index in a rat model of gout and hyperuricemia.METHODS: Fifty rats were randomly divided into five groups: blank, model, Shu-acupoint, Yuan-acupoint, and Mu-acupoint groups. A rat model of hyperuricemia was developed by intragastric administration of adenine and ethambutol. This experiment last for 90 d in total. Treatment groups underwent 3 courses of acupuncture. Each course involved a total of 10 interventions(one intervention every second day) with each intervention lasting15 min. There was a break for 10 d between courses. SUA and ALP were analyzed using an automatic biochemical analyzer and XOD was analyzed using immunofluorescence.RESULTS: Compared with the blank group, SUA and XOD levels in the model group were significantly higher and the renal index significantly improved. Compared with the model group, SUA and XOD levels in the three treatment groups decreased and the renal index significantly improved.When the three treatment groups were compared,the Mu-acupoint group showed the greatest decreases in SUA and XOD levels, followed by the Yuan-acupoint group. There was no significant difference in kidney index among the three treatment groups. There was no significant difference in ALP levels among the groups.CONCLUSION: The three treatments showed significantly reduced SUA and XOD levels compared with the control groups, possibly suggesting reduced renal damage.
基金supported by Beijing Advanced Innovation Center for Food Nutrition and Human Health(20181036).
文摘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.
基金The authors would like to thank the support of the National S&T Major Project of China(Grant No.:2018ZX09201011)the National Natural Science Foundation of China(Grant No.:81503242)the Fundamental Research Funds for the Central Universities(Grant No.:2018FZA7018).
文摘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.
文摘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.
基金supported in part by the National Natural Science Foundation of China,China[grant number 82304613]Qingdao City of Postdoctoral Program[grant number QDBSH20220202186]Shandong Provincial Natural Science Foundation,China[grant number ZR2021QH085].
文摘Snow chrysanthemum,the capitulum of Coreopsis tinctoria Nutt.,was found to possess inhibitory activity on xanthine oxidase(XO),one of the key enzymes in the pathogenesis of gout.Assisted by bioactivity-oriented isolation,a total of 16 compounds containing a new compound were obtained from the active fractions of snow chrysanthemum extract,including two aurones(1,2),four chalcones(3-6),a flavone(7),four flavonols(8-11),a flavanonol(12),three phenylpropanoids(13-15),and a new polyacetylene glycoside(16).All the isolated compounds were assayed for their inhibitory activity on XO,among which eight polyphenols(1-8)exhibited potent or moderate inhibitory activities with IC_(50) values from 0.65 to 29.11μM.The structure-activity relationship was interpreted for polyphenols(1-12).Besides,the inhibition properties of compounds 1-4 against XO were comprehensively investigated through enzyme kinetics,fluorescence quenching,and docking simula-tion.Maritimetin(1)and sulfurein(2)reversibly inhibited XO by mixed type mechanism.Okanin-4′-O-(6″-acetyl)-β-D-glucopyranoside(3)and coreopsin(4)competitively inhibited XO in reversible and irreversible manners,respectively.In addition,fluorescence quenching studies suggested that all four compounds interacted with XO through a static quenching mechanism.Molecular docking inferred that hydrogen bonds and hydro-phobic interaction played key roles in the binding process.This study revealed the XO-inhibitory activity of snow chrysanthemum and the contribution of containing aurones and chalcones to XO inhibition,making it a potential functional food ingredient for management of hyperuricemia.
基金financially supported by the National Natural Science Foundation of China(Grant No.21868003)the Guangxi Science and Technology Base and Talent Project(Grant No.Guike AD18281064)the Guangxi Natural Science Foundation(Grant No.2017GXNSFAA198265).
文摘Post-translational modifications(PTMs)by disulfide-bond formation and limited proteolysis are well-established to transform some xanthine dehydrogenase(XDH)to xanthine oxidase(XOD),which utilize NAD and oxygen as respective functionally equivalent electron acceptors,but the uncontrollability of PTMs challenges the efficient production of active XOD,and do not work for other post-translationally non-convertible pure XDHs.To overcome these limitations,this study aimed to rationally engineer the electron acceptor region of XDH to enable one-step synthesis of functional XOD without relying on PTMs.A proof-of-concept study of PTM-independent one-step synthesized XOD was initiated by rationally engineering the electron acceptor region of XDH here.Five mutants of Rhodobacter capsulatus XDH increased the catalytic activity with O_(2) as electron acceptor by up to 2124-times to commercial XODs’level.Structurally equivalent mutations of Acinetobacter baumannii XDH(AbXDH)switched it from a post-translationally non-convertible pure XDH to virtual XODs with the best turnover number and catalytic efficiency of 85.17 s^(-1)and 126.15μM^(-1) s^(-1)using O_(2) as electron acceptor,which was 45-times higher than the wild-type AbXDH utilizing NAD,outperforming commercially available XODs.The present success of electron acceptor switch by rationally refactoring the electron acceptor region of the electron transfer chain,especially engineering of the NAD-binding loop has also implicated its potential utility in other oxidoreductases as a new tool for cofactor engineering.
基金supported by the Applied Molecular Biosciences Unit-UCIBIO,which is financed by the national funds from FCT(UIDB/04378/2020)the Associate Laboratory for Green Chemistry-LAQV,which is financed by the national funds from Fundacão para a Ciência e a Tecnologia,MCTES(FCT/MCTES+3 种基金UIDB/50006/2020)by the project PTDC/QUI-QFI/31689/2017LBM wishes to thank FCT/MCTES for the CEEC-Individual 2017 Program Contract.HSF acknowledges FCT for his Ph.D.grant SFRH/BD/115396/2016the support of INCD funded by FCT and FEDER under the project 01/SAICT/2016 number 022153.
文摘In this article,quantum mechanical/molecular mechanical(QM/MM)methods were used to study the full catalytic mechanism of xanthine oxidase(XO).XO catalyzes the conversion of xanthine(XAN)to uric acid(URC),in the presence of a molybdenum cofactor(Moco).The mechanism occurs through four reaction steps.Initially,the proton from the hydroxyl group of Moco passes to Glu1261 and the activated hydroxyl group makes a nucleophilic attack on XAN.Then,a hydride is transferred from the tetrahedral intermediate to the sulfur atom of the Moco,reducing Mo(Ⅵ)to Mo(Ⅳ).In the third step,one molecule of URC is formed through its protonation by Arg880.Once this reaction is complete,FAD is reduced to FADH_(2),oxidizing Mo(Ⅳ)to its initial oxidation state of Mo(Ⅵ).The enzymatic turnover is achieved with the reaction of one water molecule with the Moco.The rate-limiting step of the full catalytic mechanism is the hydride transfer that requires a free activation barrier of 16.9 kcal mol^(−1),which closely agrees with the experimental kcat value(18.3 s^(−1)),which corresponds to approximately 15.7 kcal mol^(−1).This work also elucidates the key role played by Arg880 in the catalytic mechanism and the importance of Glu802 in the binding of the substrate.Both residues were previously shown to be important by mutagenesis studies,but their role was still not clearly understood.Additionally,it was observed that the presence of a tunnel of water molecules located close to Moco and Glu1261 is important for the enzymatic turnover.The determined transition state structures can now be used to help the development of transition-state analog inhibitors targeting XO.
基金supported by the earmarked fund for CARS(CARS-45).
文摘Current treatment of hyperuricemia relies on xanthine oxidase(XO)inhibitors that block uric acid production.This study investigated two fish maw(FM)types,from miiuy croaker and silver carp,as novel sources of peptides with XO inhibition(XOI)benefit.Alcalase 2L was the most effective protease to hydrolyze the FM.Hydrolysates from freshwater FM exhibited stronger XOI activity than hydrolysates from medicinal FM,with XOI activity of 80.33%±1.64%and 65.94%±0.08%,respectively,and IC_(50)of 9.08±0.24 mg/mL and 11.23±0.31 mg/mL,respectively.In silico screening and molecular docking simulations identified four candidate peptides,EFF and DSLGF from freshwater FM,and EQGF and PSGPQ from medicinal FM,with the highest binding affinity to the XO receptor.The binding primarily consisted of hydrogen bonds,hydrophobic interactions and cation interactions.Phe residues on peptide sequences were key contributors to XO-peptide interactions.This was further validated by DFT quantum calculations.Phenyl rings on F-3(EFF),F-5(DSLGF)and the carbonyl group of E-1(EQGF),and Q-5(PSGPQ)were identified as key reactive sites by DFT calculations.When tested in vitro,the XOI of the four peptides decreased in the order:EFF(47.54%±0.19%)>EQGF(40.13%±0.86%)>DSLGF(34.91%±0.55%)>PSGPQ(34.84%±0.12%).These findings suggest that both low-value silver carp FM and medicinal miiuy croaker FM are potential source of peptides with anti-hyperuricemia functions.Moreover,combining computational tools like molecular docking simulations and DFT could be effective in elucidating peptide-receptor target interactions and structure-activity relationships.
基金supported by the open fund of Guangdong provincial key laboratory of tea plant resources innovation and utilization(2020KF01)the Guangdong province key laboratory for green pro-cessing of natural products and product safety(202210)the Natural science foundation of Guangdong province(2023A1515010006).
文摘In this study,two novel xanthine oxidase inhibitory peptides,PDEAVAYG(820.3602 Da)and IAAGLQNTG(843.4450 Da),were purified and identified from tea protein hydrolysate,and their IC_(50) values were 0.09 mg/mL(109.71μM)and 0.24 mg/mL(284.55μM),respectively.During the gastrointestinal simulation digestion,PDEAVAYG was broken down into new peptides,while IAAGLQNTG exhibited some stability.Molecular docking results showed that hydrogen bonding,π-πstacking,and hydrophobic interactions exerted crucial effects on the interaction between peptides and xanthine oxidase.In the hyperuricemia cell model,compared to the model group,1.0 mg/mL of PDEAVAYG and IAAGLQNTG decreased cellular uric acid levels by 40.80%and 33.33%,respectively.The RNA-seq experiments revealed that PDEAVAYG could alleviate hyperuricemia by regulating mRNA expression for pro-inflammatory factors,growth factors associated with cardiovascular disease,and uric acid efflux transporter proteins in cells.This study provides a new theoretical reference for the development of functional foods or nutritional supplements using peptides with anti-hyperuricemic activity.
基金supported by the Grant(2025LHMS02013,2025LHMS03002 and 2024MS03041)the Inner Mongolia Natural Science Foundation and by the Fundamental Research Funds for Inner Mongolia University of Science&Technology(2023QNJS143)in China.
文摘This study systematically investigates the structure-activity relationship and xanthine oxidase(XO)inhibitory potential of Ferulic acid oligomers(FAOs)through DFT calculations and molecular docking.The BDE and IP values exhibit a parabolic trend from dimer to hexamer configurations,with the ferulic acid tetrameric form demonstrating optimal radical scavenging capacity.Solvent-phase analyses reveal that SPLET and SETPT mechanisms require lower activation energies in three environments compared with vacuum conditions.Moreover,HAT is the primary antioxidant pathway of FAOs.Molecular docking identifies TeFA5-8-8-5 and TeFA2-2-3-3 as dual-functional therapeutic candidates that exhibit potent antioxidant activity and XO inhibition through optimized hydrogen bonding and hydrophobic interactions.TeFA5-8-8-5 and TeFA2-2-3-3 can serve as dual-functional candidate agents for natural antioxidants and XO inhibitors.HLg and molecular orbitals can prove their stability and antioxidant mechanism.Therefore,TeFA can not only meet the industrial demand for ideal antioxidants but can also be developed into more effective gout drugs.
基金financial support provided by the National Natural Science Foundation of China(No.22078143)the Innovation and entrepreneurship training program for college students(No.202310403046).
文摘The development of natural xanthine oxidase(XO)inhibitors is an effective strategy for the treatment of hy-peruricemia.In this study,the inhibition mechanism of phloretin on XO and its joint inhibition with clinical drugs(allopurinol and febuxostat)were investigated,using multispectroscopic and molecular simulation tech-niques.The results showed that phloretin reversibly inhibited XO in a mixed type with an IC_(50) value of 31.83±0.32μM.Phloretin quenched the fluorescence of XO with a static mechanism and hydrophobic interactions were the key binding force of phloretin binding to XO.Furthermore,the interaction between phloretin and XO resulted in a more relaxed structure and less stable of the enzyme with a reduction in theα-helix content from 21.5%to 11.3%.The heatmap analysis showed that a combination of phloretin(15μM)and allopurinol(10μM)or phloretin(30μM)and febuxostat(0.01μM)exhibited the strongest synergistic effect on XO inhibition in a mixed manner.The combination of phloretin and allopurinol/febuxostat enhanced the binding affinity with XO compared to the inhibitors individually.Molecular docking indicated that phloretin,allopurinol and febuxostat bound to different sites of XO to produce a synergistic inhibition by preventing substrate access to the Mo activity center and affecting electron transfer.This study may provide theoretical references for the development of phloretin and its formulation with clinical drugs as uric acid-lowering food functional factor or drug.
基金support provided by the National Natural Science Foundation of China(Grant Nos:22478172 and 22078143)the Natural Science Foundation of Jiangxi Province(Grant No:20242BAB26103)Jiangxi Provincial Key Laboratory of Agrofood Safety and Quality(Grant No:2024SSY04192).
文摘Inhibition of xanthine oxidase(XO)activity is an effective strategy for the treatment of hyperuricemia and gout.However,some nutrients(such as lipids,proteins,and vitamins,etc)in the daily diet may affect the binding of enzyme inhibitors to XO.The effects of three unsaturated fatty acids(USFAs,namely oleic acid,linoleic acid andα-linolenic acid)on the inhibition of XO by phloretin were investigated in the study.The results showed that USFAs significantly enhanced the inhibitory effect of phloretin on XO,primarily due to the changes in secondary structure and increased binding affinity.The order of enhancement wasα-linolenic acid>oleic acid>linoleic acid.The USFAs synergistically destroyed the hydrogen bond network structure of XO with phloretin,resulting in a looser and more disordered XO structure.Moreover,phloretin formed more hydrogen bonds,hydrophobic interactions and van der Waals forces with the amino acid residues of XO in the presence of USFAs,which eventually increased the inhibitory ability of phloretin on XO.The study may provide a new perspective for the dietary nutrition intervention of the patients with hyperuricemia and gout.
基金supported by National Natural Science Foundation of China(81573645,81202538 and 81673422)CAMS Innovation Fund for Medical Sciences(CIFMS,2016-I2M-3-007)National Science and Technology Major Projects for "Major New Drugs Innovation and Development"(2013ZX09508104and 2013ZX09402203)
文摘A mangiferin aglycon derivative J99745 has been identified as a potent xanthine oxidase(XOD) inhibitor by previous in vitro study. This study aimed to evaluate the hypouricemic effects of J99745 in experimental hyperuricemia mice, and explore the underlying mechanisms. Mice were orally administered 600 mg/kg xanthine once daily for 7 days and intraperitoneally injected 250 mg/kg oxonic acid on the 7 th day to induce hyperuricemia. Meanwhile, J99745(3, 10, and 30 mg/kg), allopurinol(20 mg/kg) or benzbromarone(20 mg/kg) were orally administered to mice for 7 days. On the 7 th day,uric acid and creatinine in serum and urine, blood urea nitrogen(BUN), malondialdehyde(MDA) content and XOD activities in serum and liver were determined. Morphological changes in kidney were observed using hematoxylin and eosin(H&E) staining. Hepatic XOD, renal urate transporter 1(URAT1), glucose transporter type 9(GLUT9), organic anion transporter 1(OAT1) and ATP-binding cassette transporter G2(ABCG2) were detected by Western blot and real time polymerase chain reaction(PCR). The results showed that J99745 at doses of 10 and 30 mg/kg significantly reduced serum urate, and enhanced fractional excretion of uric acid(FEUA). H&E staining confirmed that J99745 provided greater nephroprotective effects than allopurinol and benzbromarone. Moreover, serum and hepatic XOD activities and renal URAT1 expression declined in J99745-treated hyperuricemia mice. In consistence with the ability to inhibit XOD, J99745 lowered serum MDA content in hyperuricemia mice. Our resultssuggest that J99745 exerts urate-lowering effect by inhibiting XOD activity and URAT1 expression, thus representing a promising candidate as an anti-hyperuricemia agent.
基金supported by the National Natural Science Foundation of China(Dan Du,82170905)the Program of Science and Technology Department of Sichuan Province(Dan Du,2023NSFSC1755,China)+2 种基金the State Key Laboratory of Bioactive Substance and Function of Natural Medicines,Institute of Materia Medica,Chinese Academy of Medical Sciences and Peking Union Medical College(Dan Du,GTZK202107,China)the 1.3.5 Project for Disciplines of Excellence,West China Hospital,Sichuan University(Qing Xia,ZYJC18005,China)the West China,Nursing Discipline Development Special Fund Project,Sichuan University(Xia Li,HXHL21060,China).
文摘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.
基金subsidized by the Jiangsu Key R&D plan,China(BE2019309)Construction Project of Innovative Talents Base of Guizhou Province([2016]22)which has enabled us to accomplish this study.
文摘Flos Sophorae Immaturus (FSI) possessed potential xanthine oxidase (XO) inhibitory activity as a uric acid-lowing natural product.The present work identified and quantified the free and bound polyphenols of FSI by UPLC-QTOF-MS.Then determined the primary polyphenols with XO inhibitory effect and clarified their potential mechanisms by omission experiment,interaction assay,inhibition type,and fluorescence measurements.The results revealed that nine polyphenols were detected in the free polyphenol extract and ten polyphenols were detected in the bound polyphenol extract.Meanwhile,seven polyphenols were identified as XO inhibitors,including quercetin,kaempferol,isorhamnetin,rutin,hyperoside,protocatechuic acid,and quercitrin with the IC50 values of 0.03,0.11,0.07,5.62,11.48,22.13,and 367.82 mg/mL,but their inhibition stability was lower than 24 h.Although the content of quercetin (18.87 mg/g) was not the highest,it played a crucial role to the XO inhibitory effect of FSI.Furthermore,kaempferol and isorhamnetin alone revealed the sub-additive effect with quercetin,while the combination of other polyphenols with quercetin generated the interference or antagonism effects.Quercetin,isorhamnetin,and kaempferol were mixed-type and competitive inhibitors,which significantly quenched the fluorescence intensity of XO.Moreover,the binding processes of quercetin-XO,kaempferol-XO,and isorhamnetin-XO were spontaneous and endothermic,and the hydrophobic interaction was the key driving force.In general,quercetin,kaempferol,and isorhamnetin in FSI can be used as potential XO inhibitors.
基金supported by the National Key Research and Development Program of China(2019YFD0901702)the Doctoral Startup Fund of Natural Science Foundation Program of Liaoning Province(2022-BS-301)the Basic Scientific Research Project of Education Department of Liaoning Province(Youth Project)(LJKQZ2021134).
文摘Gout, as the second major metabolic disease after cardiovascular disease. Peptides have the advantages of natural and no side effects in the treatment and prevention of gout. This study aimed to screen xanthine oxidase (XOD) inhibitory peptides from Scophthalmus maximus protein as a drug basis for the treatment of gout. The specific results are as follows: Immobilization of xanthine oxidase 25.564 μg/mg by modified magnetic beads, and modified magnetic beads can be reused three times. Three decapeptides (FSLVHYAGTV, FTNEKLQQFF and WDDMEKIWHH) were screened, the IC_(50) were 3.741, 4.046 and 2.203 mg/mL. Circular dichroism and three-dimensional fluorescence spectra showed that the inhibitory peptide would change the helical structure of XOD and the internal hydrophobic environment. Molecular docking showed that the inhibitory effect of inhibitory peptides depends on the number of unique amino acid residues in the active center of XOD enzyme. In conclusion, this study provides a method for screening anti-gout peptides, which not only solves the problem of treating gout, but also realizes the high-value utilization of marine products. In addition, this method has substantial application value because of its low cost and simple operation.
文摘Objectives:This study was conducted to investigate the xanthine oxidase(XO)inhibitory activities of 18 monomeric anthocyanins from berry fruits and roselle,and to illustrate the underlying mechanism of the most active anthocyanin delphinidin-3-O-sambubioside.Materials and Methods:Eighteen monomeric anthocyanins were prepared and purified in our laboratory.The inhibitory properties of anthocyanins were investigated by in vitro inhibitory activity studies and fluorescence quenching studies;the inhibitory mechanism was explored through kinetic studies,fluorescence quenching studies,circular dichroism analysis and computational docking simulations.Results:XO inhibitory activities of anthocyanins were related to the structures of B rings and glycosides.Among all the tested anthocyanins,delphinidin-3-O-sambubioside showed the most potent inhibitory activity with an IC_(50) of 17.1μmol/L,which was comparable to the positive control allopurinol.Spectroscopic results revealed that delphinidin-3-O-sambubioside could spontaneously interact with XO and induce conformational changes.Computational docking study indicated that delphinidin-3-O-sambubioside could bind to XO with a proper orientation,stably formed π-π interactions and hydrogen bonds with key residues,thus preventing the substrate from entering the active pocket.Conclusions:In brief,our study identified delphinidin-3-O-sambubioside as a potent XO inhibitor from natural anthocyanins,which is potentially applicable for prevention and treatment of hyperuricemia.
文摘Heart failure is currently one of the most common and most cost-intensive of the chronic diseases The main cause of chronic heart failure （CHF） is the abnormalities of both cardiac contractile performance and myocardial energy metabolism. Elevated levels of reactive oxygen species （ROS） have been proposed to contribute to both of them. Xanthine oxidoreductase （XO） is a major source of ROS in the cardiovascular system. XO inhibitors （XOIs） have been the cornerstone of the clinical management of gout and conditions associated with hyperuricemia for several decades.
