Unusual N-pyridinium amino acid-type alkaloids from roots and rhizomes of Sophora tonkinensis Gagnep.

Two previously undescribed amino acid-type alkaloids with unusual N-pyridinium cation (1-2) and six known alkaloids (3-8), were isolated from the roots and rhizomes of Sophora tonkinensis Gapnea. Their structures were characterized by UV, IR, NMR, and HRESIMS spectroscopic data. The absolute configurations of compounds 1 and 2 were established through comparison of their experimental ECD spectra to the theoretical spectra of 2 calculated by TDDFT method. The plausible biosynthetic pathway of pyridinium was also proposed. Moreover, compound 4 exhibited weak XOD inhibitory activity with the inhibition rate of 65.8% at concentration of 10 µM.

Potential Antioxidative and Anti-Hyperuricemic Components Targeting Superoxide Dismutase and Xanthine Oxidase Explored from Polygonatum Sibiricum Red.

Polygonatum sibiricum Red. (P. sibiricum) has been used as a traditional Chinese medicine with a wide range of pharmacology effects. However, the responsible bioactive compounds and their mechanisms of action concerning its antioxidative and anti-hyperuricemic activities remain unexplored. In this work, the antioxidant capacity of P. sibiricum was firstly evaluated with the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-(3ethylbenzthiazoline)-6-sulfonic acid (ABTS) and ferric-reducing antioxidant power (FRAP) assays, from which the ethyl acetate (EA) fraction exhibited the highest DPPH, ABTS radical scavenging, and ferric-reducing capacities. Meanwhile, the EA fraction displayed the highest total phenolic and flavonoid contents among the four fractions. Next, the potential ligands from the EA fraction were screened out by bio-affinity ultrafiltration liquid chromatography-mass spectrometry (UF-LC-MS) with superoxide dismutase (SOD) and xanthine oxidase (XOD). As a result, N-trans-p-coumaroyloctopamine, N-trans-feruloyloctopamine, N-trans-feruloyltyramine were identified as potential SOD ligands, while N-cis-p-coumaroyltyramine was determined as potential XOD ligand. Additionally, these four ligands effectively interact with SOD and XOD in the molecular docking analysis, with binding energies (BEs) ranging from -6.83 to -6.51 kcal/mol, and the inhibition constants (Ki) from 9.83 to 16.83 µM, which were better than the positive controls. In conclusion, our results indicated that P. sibiricum has good antioxidative and anti-hyperuricemic activities, and its corresponding active ligands targeting SOD and XOD could be explored by the UF-LC-MS method.

Natural Xanthine Oxidase Inhibitor 5-O-Caffeoylshikimic Acid Ameliorates Kidney Injury Caused by Hyperuricemia in Mice.

Xanthine oxidase (XOD) inhibition has long been considered an effective anti-hyperuricemia strategy. To identify effective natural XOD inhibitors with little side effects, we performed a XOD inhibitory assay-coupled isolation of compounds from Smilacis Glabrae Rhizoma (SGR), a traditional Chinese medicine frequently prescribed as anti-hyperuricemia agent for centuries. Through the in vitro XOD inhibitory assay, we obtained a novel XOD inhibitor, 5-O-caffeoylshikimic acid (#1, 5OCSA) with IC50 of 13.96 µM, as well as two known XOD inhibitors, quercetin (#3) and astilbin (#6). Meanwhile, we performed in silico molecular docking and found 5OCSA could interact with the active sites of XOD (PDB ID: 3NVY) with a binding energy of -8.6 kcal/mol, suggesting 5OCSA inhibits XOD by binding with its active site. To evaluate the in vivo effects on XOD, we generated a hyperuricemia mice model by intraperitoneal injection of potassium oxonate (300 mg/kg) and oral gavage of hypoxanthine (500 mg/kg) for 7 days. 5OCSA could inhibit both hepatic and serum XOD in vivo, together with an improvement of histological and multiple serological parameters in kidney injury and HUA. Collectively, our results suggested that 5OCSA may be developed into a safe and effective XOD inhibitor based on in vitro, in silico and in vivo evidence.

Flower beverages of native medicinal plants from Argentina (Acacia caven, Geoffroea decorticans and Larrea divaricata) as antioxidant and anti-inflammatory.

ETHNOPHARMACOLOGICAL RELEVANCE: Herbal beverages have been used as a natural part of the medicinal and food culture in northwestern Argentina. The flower beverages (infusion or decoction) of Acacia caven, Geoffroea decorticans and Larrea divaricata, three native species from arid and semiarid regions of Argentina are widely used as anti-inflammatory and anti-rheumatic by several local communities. AIM OF THE STUDY: The aim of this study was to analyze the phytochemical composition of some Argentine flower beverage and to validate its traditional use as an antioxidant and anti-inflammatory agent. MATERIALS AND METHODS: Phenolic profiles from all flower infusions and decoctions were analyzed by both spectrophotometric analysis and HPLC-DAD. ABTS•+; the scavenging activity of both hydrogen peroxide and hydroxyl radical was determined and finally, their ability to inhibit pro-inflammatory enzymes, such as xanthine oxidase (XOD), and lipoxygenase (LOX) was also assessed. RESULTS: The flower beverages of all assayed species showed a high level of phenolic compounds with similar chromatographic patterns in both infusions and decoctions of each plant species, the major components of which have been identified. The flower beverages, especially G. decorticans infusion and decoctions, displayed an important antioxidant activity (SC50 values between 18.14 and 47 µg/mL) through different mechanisms; all of them were able to inhibit the XOD enzyme activity and, consequently, the formation of uric acid and reactive oxygen species, the primary cause of arthritis-related diseases. The most active beverages as XOD inhibitor were G. decorticans flower infusion and decoctions (IC50 values of 20 and 35 µg/mL, respectively). Pro-inflammatory enzymes, such as LOX, were also inhibited by infusions and decoctions of G. decorticans, L. cuneifolia and A caven flowers, lessening inflammation mediators in all beverages. CONCLUSIONS: The present work validates the traditional medicinal use of flower beverages from Argentina as an anti-rheumatic and anti-inflammatory agent as it has been used for hundreds of years in several pathologies associated with oxidative stress.

Effect of Different Extracts of Thlaspi Herba on Gut Microbiota of Hyperuricemia Mice / 中国实验方剂学杂志

Objective:To explore the effect of different extracts of Thlaspi Herba on the gut microbiota of hyperuricemia mice， and to reveal the substance basis and mechanism of its hypouricemic activity. Method:Eighty-eight male Kunming mice were divided into 11 groups， including blank group， model group， allopurinol group， high and low dose groups of petroleum ether extract， high and low dose groups of ethyl acetate extract， high and low dose groups of <italic>n</italic>-butanol extract， high and low dose groups of total flavonoids extract. Mice in the blank group were given 0.5% sodium carboxymethylcellulose by gavage， and the other groups were given oteracil potassium （500 mg·kg^-1） by gavage to duplicate the hyperuricemia model. After modeling for several hours， the blank group and the model group were given distilled water by gavage， while mice in the allopurinol group were given allopurinol suspension （50 mg·kg^-1）， and mice in each treatment group were given high and low doses of corresponding extract （5， 2.5 g·kg^-1）. The serum uric acid （SUA） level and xanthine oxidase （XOD） activity were measured after 14 days. Fresh feces were collected for 16S rDNA sequencing. Result:Compared with the blank group， SUA level and XOD activity of model group were significantly increased （<italic>P</italic><0.05）. Compared with the model group， SUA level and XOD activity of the allopurinol group were significantly decreased （<italic>P</italic><0.01）. After intervention， SUA level were significantly decreased （<italic>P</italic><0.05， <italic>P</italic><0.01）， except for high dose and low dose groups of petroleum ether extract and low dose group of total flavonoids extract， XOD activity was significantly inhibited in low dose group of petroleum ether extract， high dose group of total flavonoids extract， and high and low dose groups of <italic>n</italic>-butanol extract （<italic>P</italic><0.05， <italic>P</italic><0.01）. The high dose group of total flavonoids extract was the most significant. The results of flora sequencing showed that <italic>α</italic> diversity and abundance of the model group changed significantly， and Bacteroidetes， Firmicutes and Lactobacillaceae were significantly correlated with XOD activity. After intervention， the operational taxonomic unit （OTU）， ACE， Chao1 and Shannon indexes of the high and low dose groups of total flavonoids extract were significantly increased （<italic>P</italic><0.05， <italic>P</italic><0.01）. Relative abundance of Bacteroidetes in low dose group of ethyl acetate extract， high dose group of total flavonoids extract， and high and low dose groups of <italic>n</italic>-butanol extract was significantly decreased （<italic>P</italic><0.01）， and the relative abundance of Firmicutes was significantly increased （<italic>P</italic><0.01）. The relative abundance of Lactobacillaceae in low dose group of <italic>n</italic>-butanol extract and high dose group of total flavonoids extract was significantly increased （<italic>P</italic><0.01）. Conclusion:The effective part of Thlaspi Herba for reducing uric acid is mainly flavonoids， the improvement of SUA level and XOD activity by affecting gut microbiota such as Lactobacillaceae， Bacteroidetes and Firmicutes， may be one of its mechanisms.

Baicalein alleviates hyperuricemia by promoting uric acid excretion and inhibiting xanthine oxidase.

BACKGROUND: Insufficient renal urate excretion and/or overproduction of uric acid (UA) are the dominant causes of hyperuricemia. Baicalein (BAL) is widely distributed in dietary plants and has extensive biological activities, including antioxidative, anti-inflammatory and antihypertensive activities. PURPOSE: To investigate the anti-hyperuricemic effects of BAL and the underlying mechanisms in vitro and in vivo. METHODS: We investigated the inhibitory effects of BAL on GLUT9 and URAT1 in vitro through electrophysiological experiments and 14C-urate uptake assays. To evaluate the impact of BAL on serum and urine UA, the expression of GLUT9 and URAT1, and the activity of xanthine oxidase (XOD), we developed a mouse hyperuricemia model by potassium oxonate (PO) injection. Molecular docking analysis based on homology modeling was performed to explain the predominant efficacy of BAL compared with the other test compounds. RESULTS: BAL dose-dependently inhibited GLUT9 and URAT1 in a noncompetitive manner with IC50 values of 30.17 ± 8.68 µM and 31.56 ± 1.37 µM, respectively. BAL (200 mg/kg) significantly decreased serum UA and enhanced renal urate excretion in PO-induced hyperuricemic mice. Moreover, the expression of GLUT9 and URAT1 in the kidney was downregulated, and XOD activity in the serum and liver was suppressed. The docking analysis revealed that BAL potently interacted with Trp336, Asp462, Tyr71 and Gln328 of GLUT9 and Ser35 and Phe241 of URAT1. CONCLUSION: These results indicated that BAL exerts potent antihyperuricemic efects through renal UA excretal promotion and serum UA production. Thus, we propose that BAL may be a promising treatment for the prevention of hyperuricemia owing to its multitargeted inhibitory activity.

Two new phenylpropanoid glycosides from Lagotis brachystachya Maxim and their Xanthione Oxidase inhibitions.

Two new phenylpropanoid glycosides lagotiside C and D, along with 11 known compounds were isolated from the whole plant of Lagotis brachystachya Maxim. The structures of lagotiside C and D was elucidated on the basis of spectroscopic data analysis. Moreover, all isolated components were evalued for the inhibition on Xanthione Oxidase (XOD) activity in vitro. Results indicated that all the compounds exhibited inhibitory effects on XOD with inhibition ratio in the range of 6.35%-83.69%, which suggested that Lagotis brachystachya could be served as an XOD inhibitor.

Epigallocatechin gallate reduces uric acid levels by regulating xanthine oxidase activity and uric acid excretion in vitro and in vivo.

BACKGROUND: This study investigates the effect of epigallocatechin gallate (EGCG) from tea leaves on hyperuricemia and explores the underlying mechanisms in vitro and in vivo. METHODS: The effects of EGCG on proliferation of BRL 3A rat liver cells were evaluated by CCK8 and after stimulation by xanthine the uric acid and xanthine oxidase (XOD) levels were evaluated by a kit; In an in vivo experiment, rats were treated with oxonic acid potassium salt combined with ethylamine pyrimidine to induce high uric acid hematic disease (7 days), The serum uric acid levels and XOD levels were evaluated by a kit, The expressions of OTA1 and GLUT9 were detected by RT-qPCR and Immunohistochemical. RESULTS: EGCG had no effect on proliferation, and significantly reduced serum uric acid levels and inhibited XOD activity (P<0.05). The rat model exhibited a significant rise in blood uric acid levels (54.59 mg/dL), and EGCG significantly reduced the high level of serum uric acid and inhibited XOD activity in the serum and liver tissues (P<0.05). RT-PCR showed that EGCG significantly increased mOAT1 expression in the kidney tissues and reduced mGLUT9 expression (P<0.05). Immunohistochemical results showed that EGCG significantly increased OAT1 expression in the kidney tissues and decreased GLUT9 expression (P<0.05). CONCLUSIONS: These results demonstrate that EGCG has obvious anti-hyperuricemia effects in vitro and in vivo via the inhibition of XOD activity and GLUT9 expression and the promotion of OAT1 expression.

[Research on XOD captured components in Lagotis brevituba based on UPLC-Q-TOF-MS and molecular docking technology].

Potential xanthine oxidase (XOD) inhibitors in Lagotis brevituba were captured by using affinity and ultrafiltration. The structures of the captured components were identified by ultra-performance liquid chromatography coupled with Q-TOF mass spectrometry (UPLC-Q-TOF-MS). The binding intensity and binding mechanism between the captured components and XOD were analyzed by using molecular docking software Autodock 4.2. A total of 17 compounds were identified, including 9 flavonoids, 5 phenolic acids and 3 triterpenes. Molecular docking results showed that all the captured components could be spontaneously bound with XOD mainly via hydrogen bond, Van der Waals' force and hydrophobic interaction. From the perspective of binding energy and scoring function, the collected fractions all had potential prospects for XOD inhibitors, and the flavonoid luteolin-3',7 glucuronide had the best effect. The results also showed that affinity and ultrafiltration, ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) and molecular docking technology can provide a powerful tool for the analysis of XOD inhibitor components in natural products.

4-(2-(4-chlorophenyl)-1-((4-chlorophenyl)amino)ethyl)benzene-1, 3-diol is a potential agent for gout therapy as a dual inhibitor of XOD and NLRP3.

BACKGOUND: Gout is an inflammatory arthritis characterized by abrupt self-limiting attacks of inflammation caused by precipitation of monosodium urate crystals (MSU) in the joint. Both anti-hyperuricemia and anti-inflammation could be gout therapeutic strategies, whereas ideal drugs for gout treatment are deficient. PURPOSE: 4-(2-(4-chlorophenyl)-1-((4-chlorophenyl)amino)ethyl)benzene-1, 3-diol (CBED) was obtained from a cluster of deoxybenzoins derivatives synthesized by our research group with potent anti-hyperuricemic and anti-inflammatory activities, which was expected to be a dual inhibitor of xanthine oxidase (XOD) and NOD-like receptor protein 3 (NLRP3). This study aimed to investigate effects of CBED on XOD and NLRP3 in vitro, as well as the possible mechanisms by which CBED improved gout in vivo. METHODS: After molecular docking detection, inhibitory effects of CBED on XOD and NLRP3 were evaluated in vitro. Subsequently, hyperuricemia and acute gouty arthritis animal models were established by potassium oxonate or MSU, respectively. After CBED treatment, serum uric acid levels, synovial interleukin (IL)-1ß concentrations, hepatic XOD activities, as well as synovial morphological changes were examined. More importantly, synovial expressions of NLRP3 inflammasome components including NLRP3, apoptosis-associated speck-like protein (ASC) and caspase-1 in rats were analyzed by immunofluorescence and western blot. RESULTS: In vitro, CBED obviously inhibited XOD activity with an IC50 value of 3.87 µM, moreover, it effectively inhibited MSU-induced NLRP3 inflammasome activation and IL-1ß over-production in THP-1 cells. In addition, CBED dose-dependently decreased serum uric acid levels suppressed hepatic XOD activities in oxonate-induced hyperuricemic mice. On the other hand, CBED significantly improved MSU-induced ankle swelling and histopathological damage with elevated IL-1ß. In addition, NLRP3 inflammasome activation could be blocked by CBED treatment in rats with acute gouty arthritis. Notbly, CBED exhibited no effects on all these indicators in normal animals, predicting its safety. CONCLUSIONS: CBED might serve as a dual XOD and NLRP3 inhibitor for treatment of gout.

Modeling and optimizing inhibitory activities of Nelumbinis folium extract on xanthine oxidase using response surface methodology.

Xanthine oxidase (XOD), which could oxidize hypoxanthine to xanthine and then to uric acid, is a key enzyme in the pathogenesis of hyperuricemia and also a well-known target for the drug development to treat gout. In our study, the total alkaloids of Nelumbinis folium markedly inhibited XOD activity, with IC50 value being 3.313µg/mL. UHPLC-Q-TOF-MS and 3D docking analysis indicated that roemerine was a potential active ingredient. A response surface methodology combined with central composite design experiment was further developed and validated for the optimization of the reaction conditions between the total alkaloids of Nelumbinis folium and XOD, which could be considered as a meaningful research for the development of XOD inhibitor rapidly and sensitively.

Pallidifloside D from Smilax riparia enhanced allopurinol effects in hyperuricemia mice.

Pallidifloside D, a saponin glycoside constituent from the total saponins of Smilax riparia, had been proved to be effective in hyperuricemic control. Allopurinol is a commonly used medication to treat hyperuricemia and its complications. In this study, we evaluated whether Pallidifloside D could enhance allopurinol's effects by decreasing the serum uric acid level in a hyperuricemic mouse model induced by potassium oxonate. We found that, compared with allopurinol alone, the combination of allopurinol and Pallidifloside D significantly decreased the serum uric acid level and increased the urine uric acid level (both P<0.05), leading to the normalized serum and urine uric acid concentrations. Data on serum, urine creatinine and BUN supported these observations. Our results showed that the synergistic effects of allopurinol combined with Pallidifloside D were linked to the inhibition of both serum and hepatic xanthine oxidase (XOD), the down-regulation of renal mURAT1 and mGLUT9, and the up-regulation of mOAT1. Our data may have a potential value in clinical practice in the treatment of gout and other hyperuricemic conditions.

Effects of imperatorin, the active component from Radix Angelicae (Baizhi), on the blood pressure and oxidative stress in 2K,1C hypertensive rats.

The 2-kidney, 1-clip (2K,1C) model of hypertension was used to investigate the potential antihypertensive and antioxidant effect of imperatorin extracted from the root of radix angelicae. After 10 weeks treatment of imperatorin, mean blood pressure (MBP) of 2K,1C hypertensive rats was obtained, and superoxide dismutase (SOD), nitric oxide (NO) and nitric oxide synthase (NOS) were measured. Malondialdehyde (MDA) and glutathione (GSH) levels, catalase (CATA), xanthine oxidase (XOD), angiotensinII (Ang II) and endothelin (ET) levels of kidney were evaluated with commercial kits. Nicotinamide adenine dinucleotidephosphate (NADPH) oxidase subunits of the renal cortial tissues were determined by RT-PCR and Western blot. 8-Iso-prostaglandin F2α (8-iso-PGF2α) of 24h urinary excretion was also measured by ELISA. MBP was significantly reduced by treatment with IMP (6.25, 12.5 and 25 mg/kg/day, i.g.) in 2K,1C hypertensive rats. Meanwhile, we found that renal CATA and XOD activities, GSH levels, plasma NO and NOS contents were significantly increased in IMP-treated groups. Plasma ET, renal Ang II levels, MDA and the 24h urinary excretion of 8-iso-PGF2α in the IMP treated group were lower than control SD group. After that, we found the mRNA expressions and protein levels of NADPH oxidase subunits in the clipped kidney were markedly reduced after IMP treated in 2K,1C hypertensive rats. IMP showed antihypertensive and antioxidant effects in the renal injury of renovascular hypertensive rats, suggesting that IMP could be of therapeutic use in preventing renal injury related hypertension.