Objective: To observe the antioxidative effects of N-(9,10-anthraquinone-2-ylcarbonyl) xanthine oxidase inhibitors (NAY) in vitro and in vivo models of hyperuricemia and explore the mechanism. Methods: A classical experimental method of acute toxicity and a chronic toxicity test were used to compare the toxic effects of different doses of NAY in mice. The hyperuricemia mouse model was established by gavage of potassium oxonate in vivo. After treatment with different doses of NAY (low dose: 10 mg/kg, medium dose: 20 mg/kg, and high dose: 40 mg/kg) and allopurinol (positive drug, 10 mg/kg), observe the levels of uric acid (UA), creatinine (CRE), and urea nitrogen (BUN) in urine and serum, respectively, and detect the activities of xanthine oxidase in the liver. The hyperuricemia cell model was induced by adenosine and xanthine oxidase in vitro. The cells were given different doses of NAY (50, 100, and 200 μmol/L) and allopurinol (100 μmol/L). Then the culture supernatant UA level of the medium was measured. The next step was to detect the xanthine oxidase activity in the liver and AML12 cells, and the levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), and NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) inflammatory factors in the kidney and serum of mice. Western blot was used to detect xanthine oxidase protein expression in mouse liver tissue and AML12 cells, ASC, Caspase-1, NLRP3, GLUT9, OAT1, and OAT3 protein expression in mouse kidney tissue and HK-2 cells. Hematoxylin-eosin staining was used to stain the liver and kidney tissues of mice and observe the tissue lesions. Results: NAY had little effect on blood routine and biochemical indexes of mice, but significantly reduced the serum UA level. NAY significantly reduced the level of UA in hyperuricemia mice and cells by inhibiting xanthine oxidase activity and reduced the levels of TNF-α, IL-6, and other inflammatory factors in serum and kidney of mice. NAY can inhibit inflammation by inhibiting the NLRP3 pathway. In addition, NAY can downregulate GLUT9 protein expression and upregulate OAT1 and OAT3 protein expression to reduce the UA level by promoting UA excretion and inhibiting UA reabsorption. Conclusion: These findings suggested that NAY produced dual hypouricemic actions. On the one hand, it can inhibit the formation of UA by inhibiting xanthine oxidase inhibitors activity, and on the other hand, it can promote the excretion of UA by regulating the UA transporter. It provides new ideas for the development of hyperuricemia drugs in the future.

Glyceryl trinitrate (GTN) has found widespread use for the treatment of angina pectoris, a pathological condition manifested by chest pain resulting from insufficient blood supply to the heart. Metabolic conversion of GTN, a nitric oxide (NO) pro-drug, into NO induces vasodilation and improves blood flow. Patients develop tolerance to GTN after several weeks of continuous use, limiting the potential for long-term therapy. The mechanistic cause of nitrate tolerance is relatively unknown. We developed a cell culture model of nitrate tolerance that utilizes stable isotopes to measure metabolism of 15N3-GTN into 15N-nitrite. We performed global metabolomics to identify the mechanism of GTN-induced nitrate tolerance and to elucidate the protective role of vitamin C (ascorbic acid). Metabolomics analyses revealed that GTN impaired purine metabolism and depleted intracellular ATP and GTP. GTN inactivated xanthine oxidase (XO), an enzyme that is critical for the metabolic bioactivation of GTN into NO. Ascorbic acid prevented inactivation of XO, resulting in increased NO production from GTN. Our studies suggest that ascorbic acid has the ability to prevent nitrate tolerance by protecting XO, but not aldehyde dehydrogenase (another GTN bioactivating enzyme), from GTN-induced inactivation. Our findings provide a mechanistic explanation for the previously observed beneficial effects of ascorbic acid in nitrate therapy.

Hesperetin is a natural flavonoid with many biological activities. In view of hyperuricemia treatment, the effects of hesperetin in vivo and in vitro, and the underlying mechanisms, were explored. Hyperuricemia models induced by yeast extract (YE) or potassium oxonate (PO) in mice were created, as were models based on hypoxanthine and xanthine oxidase (XOD) in L-O2 cells and sodium urate in HEK293T cells. Serum level of uric acid (UA), creatinine (CRE), and urea nitrogen (BUN) were reduced significantly after hesperetin treatment in vivo. Hesperetin provided hepatoprotective effects and inhibited xanthine oxidase activity markedly, altered the level of malondialdehyde (MDA), glutathione peroxidase (GSH-PX) and catalase (CAT), downregulated the XOD protein expression, toll-like receptor (TLR)4, nucleotide binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, interleukin-18 (IL-18), upregulated forkhead box O3a (FOXO3a), manganese superoxide dismutase (MnSOD) in a uric acid-synthesis model in mice. Protein expression of organic anion transporter 1 (OAT1), OAT3, organic cationic transporter 1 (OCT1), and OCT2 was upregulated by hesperetin intervention in a uric acid excretion model in mice. Our results proposal that hesperetin exerts a uric acid-lowering effect through inhibiting xanthine oxidase activity and protein expression, intervening in the TLR4-NLRP3 inflammasome signaling pathway, and up-regulating expression of FOXO3a, MnSOD, OAT1, OAT3, OCT1, and OCT2 proteins. Thus, hesperetin could be a promising therapeutic agent against hyperuricemia.

Background: Gout is a common arthritis, due to deposition of monosodium urate (MSU) crystals which results in IL-1β secretion by tissue-resident macrophages. Xanthine oxidase (XO) catalyzes uric acid (UA) production and in the process, reactive oxygen species (ROS) are generated which contributes to NLRP3 inflammasome activation. Protein phosphatase 2A (PP2A) may be involved in regulating inflammatory pathways in macrophages. The objective of this study was to investigate whether PP2A regulates gout inflammation, mediated by XO activity modulation. We studied UA and ROS generations in MSU stimulated murine bone marrow derived macrophages (BMDMs) in response to fingolimod phosphate, a PP2A activator, and compared its anti-inflammatory efficacy to that of an XO inhibitor, febuxostat. Methods: BMDMs were stimulated with MSU, GM-CSF/IL-1β or nigericin ± fingolimod (2.5 μM) or febuxostat (200 μM) and UA levels, ROS, XO, and PP2A activities, Xdh (XO) expression and secreted IL-1β levels were determined. PP2A activity and IL-1β in MSU stimulated BMDMs ± N-acetylcysteine (NAC) (10 μM) ± okadaic acid (a PP2A inhibitor) were also determined. M1 polarization of BMDMs in response to MSU ± fingolimod treatment was assessed by a combination of iNOS expression and multiplex cytokine assay. The in vivo efficacy of fingolimod was assessed in a murine peritoneal model of acute gout where peritoneal lavages were studied for pro-inflammatory classical monocytes (CMs), anti-inflammatory nonclassical monocytes (NCMs) and neutrophils by flow cytometry and IL-1β by ELISA. Results: Fingolimod reduced intracellular and secreted UA levels (p < 0.05), Xdh expression (p < 0.001), XO activity (p < 0.001), ROS generation (p < 0.0001) and IL-1β secretion (p < 0.0001), whereas febuxostat enhanced PP2A activity (p < 0.05). NAC treatment enhanced PP2A activity and reduced XO activity and PP2A restoration mediated NAC's efficacy as co-treatment with okadaic acid increased IL-1β secretion (p < 0.05). Nigericin activated caspase-1 and reduced PP2A activity (p < 0.001) and fingolimod reduced caspase-1 activity in BMDMs (p < 0.001). Fingolimod reduced iNOS expression (p < 0.0001) and secretion of IL-6 and TNF-α (p < 0.05). Fingolimod reduced CMs (p < 0.0001), neutrophil (p < 0.001) and IL-1β (p < 0.05) lavage levels while increasing NCMs (p < 0.001). Conclusion: Macrophage PP2A is inactivated in acute gout by ROS and a PP2A activator exhibited a broad anti-inflammatory effect in acute gout in vitro and in vivo.

Recently, progression of chronic renal failure (CRF) has been closely associated with gut microbiota dysbiosis and intestinal metabolite-derived microinflammation. In China, total flavones of Abelmoschus manihot (TFA), a component of Abelmoschus manihot, has been widely used to delay CRF progression in clinics for the past two decades. However, the overall therapeutic mechanisms remain obscure. In this study, we designed experiments to investigate the renoprotective effects of TFA in CRF progression and its underlying mechanisms involved in gut microbiota and microinflammation, compared with febuxostat (FEB), a potent non-purine selective inhibitor of xanthine oxidase.

Background and objective: Doxorubicin is extensively utilized chemotherapeutic drug, and it causes damage to the heart, liver, and kidneys through oxidative stress. Theobroma cacao L (cocoa) is reported to possess protective effects against several chemical-induced organ damages and also acts as an anticancer agent. The study aimed to determine whether the administration of cocoa bean extract reduces doxorubicin-induced organ damage in mice with Ehrlich ascites carcinoma (EAC) without compromising doxorubicin efficacy. Methodology: Multiple in vitro methods such as cell proliferation, colony formation, chemo-sensitivity, and scratch assay were carried out on cancer as well as normal cell lines to document the effect of cocoa extract (COE) on cellular physiology, followed by in vivo mouse survival analysis, and the organ-protective effect of COE on DOX-treated animals with EAC-induced solid tumors was then investigated. In silico studies were conducted on cocoa compounds with lipoxygenase and xanthine oxidase to provide possible molecular explanations for the experimental observations. Results: In vitro studies revealed potent selective cytotoxicity of COE on cancer cells compared to normal. Interestingly, COE enhanced DOX potency when used in combination. The in vivo results revealed reduction in EAC and DOX-induced toxicities in mice treated with COE, which also improved the mouse survival time; percentage of lifespan; antioxidant defense system; renal, hepatic, and cardiac function biomarkers; and also oxidative stress markers. COE reduced DOX-induced histopathological alterations. Through molecular docking and MD simulations, we observed chlorogenic acid and 8'8 methylenebiscatechin, present in cocoa, to have the highest binding affinity with lipoxygenase and xanthine oxidase, which lends support to their potential in ameliorating oxidative stress. Conclusion: The COE reduced DOX-induced organ damage in the EAC-induced tumor model and exhibited powerful anticancer and antioxidant effects. Therefore, COE might be useful as an adjuvant nutritional supplement in cancer therapy.

Phellodendri Chinese Cortex has long been used to treat hyperuricemia and gout. Berberine (BBR), its characteristic ingredient, has also been shown to be effective in alleviating monosodium urate crystals-triggered gout inflammation in vitro and in vivo. Dihydroberberine (DHB) is a hydrogenated derivative of BBR that showed improved in vivo efficacy on many metabolic disorders. However, its anti-hyperuricemia effect remains underexplored. In the present work, the hypouricemic and renoprotective effects of DHB on hyperuricemic mice were investigated. The hyperuricemic mice model was induced by intraperitoneal injection of potassium oxonate (PO, 300 mg/kg) combined with intragastric administration of hypoxanthine (HX, 300 mg/kg) for 7 days. Different dosages of DHB (25, 50 mg/kg), BBR (50 mg/kg) or febuxostat (Feb, 5 mg/kg) were orally given to mice 1 h after modeling. The molecular docking results showed that DHB effectively inhibited xanthine oxidase (XOD) by binding with its active site. In vitro, DHB exhibited significant XOD inhibitory activity (IC50 value, 34.37 μM). The in vivo results showed that DHB had obvious hypouricemic and renoprotective effects in hyperuricemic mice. It could not only lower the uric acid and XOD levels in serum, but also suppress the activities of XOD and adenosine deaminase (ADA) in the liver. Furthermore, DHB noticeably down-regulated the renal mRNA and protein expression of XOD. Besides, DHB remarkably and dose-dependently ameliorated renal damage, as evidenced by considerably reducing serum creatinine and blood urea nitrogen (BUN) levels, inflammatory cytokine (TNF-α, IL-1β, IL-6 and IL-18) levels and restoring kidney histological deteriorations. Further mechanistic investigation showed that DHB distinctly down-regulated renal mRNA and protein levels of URAT1, GLUT9, NOD-like receptor 3 (NLRP3), apoptosis-associated speck-like (ASC), caspase-1 and IL-1β. Our study revealed that DHB had outstanding hypouricemic and renoprotective effects via suppressing XOD, URAT1, GLUT9 and NLRP3 inflammasome activation in the kidney.

Bupleurum chinense DC (Chaihu)-Paeonia lactiflora Pall (Baishao) is among the most accepted herb pairs in many classic antidepressant prescriptions. Our previous study has shown that the Chaihu-Baishao herb pair (CBHP) had a better antidepressant effect than Chaihu or Baishao. Nevertheless, the synergistic antidepressant mechanism of this herb pair was not clearly understood. This study aimed to investigate the compatibility mechanism of Chaihu and Baishao for treating depression through a strategy of non-targeted metabolomics combined with targeted quantitative analysis and molecular biology techniques. First, the compatibility effects of CBHP were assessed by the chronic unpredictable mild stress (CUMS) rat model. Next, cortex metabolomics based on ultra-high-performance liquid chromatography combined with quadrupole orbitrap mass spectrometry (UPLC-Q-Orbitrap/MS) was used to discover the metabolic pathway that was synergistically regulated by CBHP. Based on the results of metabolomics analysis, metabolites were quantitatively validated by UPLC-MS/MS combined with the MRM mode in the crucial metabolic pathway. In addition, the signaling pathway associated with this metabolic pathway was detected by molecular biology techniques to further identify the biological meaning of the crucial metabolite on the synergistic antidepressant effect of CBHP. The antidepressant effect of CBHP was significantly better than that of Chaihu or Baishao single administrated in the behavioral test. According to cortex metabolomics, a total of 21 differential metabolites were screened out, and purine metabolism was selected as the crucial metabolic pathway by the enrichment analysis of differential metabolites. Subsequently, purine metabolism was confirmed as disorder in the CUMS group by targeted quantitative analysis, CBHP regulated more purine metabolites (six) than individual administration (two and two). The results showed that purine metabolism was modulated by CBHP through synergistically decreasing xanthine levels and inhibiting the conversion of xanthine dehydrogenase (XDH) to xanthine oxidase (XOD). Finally, the synergistic regulation effect of CBHP on xanthine synthesis was found to be related to inhibition of malondialdehyde (MDA) production, Nod-like receptor protein 3 (NLRP3) inflammasome expression, and interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α secretion. The present study demonstrated that the regulation of purine metabolism, the suppression of oxidative stress, and inflammatory responses in the cortex were involved in the synergistic antidepressant effect of CBHP.

Gout is a type of arthritis that causes painful inflammation in one or more joints. In gout, elevation of uric acid in the blood triggers the formation of crystals, causing joint pain. Malaysia is a mega-biodiversity country that is rich in medicinal plants species. Therefore, its flora might offer promising therapies for gout. This article aims to systematically review the anti-gout potential of Malaysian medicinal plants. Articles on gout published from 2000 to 2017 were identified using PubMed, Scopus, ScienceDirect, and Google Scholar with the following keyword search terms: "gout," "medicinal plants," "Malaysia," "epidemiology," "in vitro," and "in vivo." In this study, 85 plants were identified as possessing anti-gout activity. These plants had higher percentages of xanthine oxidase inhibitory activity (>85%); specifically, the Momordica charantia, Chrysanthemum indicum, Cinnamomum cassia, Kaempferia galanga, Artemisia vulgaris, and Morinda elliptica had the highest values, due to their diverse natural bioactive compounds, which include flavonoids, phenolics, tannin, coumarins, luteolin, and apigenin. This review summarizes the anti-gout potential of Malaysian medicinal plants but the mechanisms, active compounds, pharmacokinetics, bioavailability, and safety of the plants still remain to be elucidated.

Neutrophils are the primary immune cells in innate immunity, which are related to various inflammatory diseases. Astragalus mongholicus Bunge is a Chinese medicinal herb used to treat various oxidative stress-related inflammatory diseases. However, there are limited studies that elucidate the effects of Astragalus mongholicus Bunge in human neutrophils. In this study, we used isolated human neutrophils activated by various stimulants to investigate the anti-inflammatory effects of Astragalus mongholicus Bunge water extract (AWE). Cell-free assays were used to examine free radicals scavenging capabilities on superoxide anion, reactive oxygen species (ROS), and nitrogen-centered radicals. Imiquimod (IMQ) induced psoriasis-like skin inflammation mouse model was used for investigating anti-psoriatic effects. We found that AWE inhibited superoxide anion production, ROS generation, and elastase release in human neutrophils, which exhibiting a direct anti-neutrophil effect. Moreover, AWE exerted a ROS scavenging ability in the 2,2'-Azobis (2-amidinopropane) dihydrochloride assay, but not superoxide anion in the xanthine/xanthine oxidase assay, suggesting that AWE exhibited anti-oxidation and anti-inflammatory capabilities by both scavenging ROS and by directly inhibiting neutrophil activation. AWE also reduced CD11b expression and adhesion to endothelial cells in activated human neutrophils. Meanwhile, in mice with psoriasis-like skin inflammation, administration of topical AWE reduced both the affected area and the severity index score. It inhibited neutrophil infiltration, myeloperoxidase release, ROS-induced damage, and skin proliferation. In summary, AWE exhibited direct anti-inflammatory effects by inhibiting neutrophil activation and anti-psoriatic effects in mice with IMQ-induced psoriasis-like skin inflammation. Therefore, AWE could potentially be a pharmaceutical Chinese herbal medicine to inhibit neutrophilic inflammation for anti-psoriasis.

Objective: Serum uric acid is associated with tumor progression and hepatocarcinogenesis. Here, we aimed to determine whether serum uric acid is related to the survival time of patients with hepatocellular carcinoma (HCC) and whether the inhibition of uric acid production affects the progression and survival of rats with HCC. Methods: The follow-up data of 288 patients with advanced HCC were analyzed. Ten purine metabolites in serum and liver samples of diethylnitrosamine (DEN)-induced HCC rats were quantitatively determined by an established UPLC-MS/MS method. On this basis, febuxostat, a specific inhibitor of xanthine oxidase (XOD), was used to interfere with HCC rats. Results: The serum uric acid level of HCC patients was significantly negatively correlated with survival days (r = -0.155). The median survival time was 133.5 days in the high uric acid group (>360 μmol/L, n = 80) and 176.0 days in the normal serum uric acid group (<360 μmol/L, n = 208, p = 0.0013). The levels of hypoxanthine, guanine, and uric acid; XOD activity; and xanthine dehydrogenase mRNA expression in the serum or liver samples of HCC rats were significantly upregulated compared with those in the control group. After febuxostat intervention in DEN-induced HCC rats, the number of atypical cells and inflammatory cells decreased significantly; the serum alpha fetoprotein level and Fisher's ratio tended to return to normal; the median survival time increased from 36 to 96 days (p = 0.08). In addition, serum malondialdehyde, superoxide dismutase, and glutathione activity nearly returned to the level of the healthy control group. Conclusion: The elevation of serum uric acid implies a risk of poor survival in advanced HCC patients and Febuxostat can reduce the generation of reactive oxygen species, thereby playing a role in delaying the progression of liver cancer.

Endothelium dysfunction induced by reactive oxygen species (ROS) is an important initial event at the onset of myocardial ischemia/reperfusion in which the Egr-1 transcription factor often serves as a master switch for various damage pathways following reperfusion injury. We hypothesized that an intracellular ROS/MAPK/Egr-1 signaling pathway is activated in cardiac microvascular endothelial cells (CMECs) following hypoxia/reoxygenation (H/R). ROS generation, by either H/R or the ROS donor xanthine oxidase-hypoxanthine (XO/HX) activated all three MAPKs (ERK1/2, JNK, p38), and induced Egr-1 expression and Egr-1 DNA-binding activity in CMECs, whereas ROS scavengers (EDA and NAC) had the opposite effect following H/R. Inhibitors of all three MAPKs individually inhibited induction of Egr-1 expression by H/R in CMECs. Moreover, N-n-butyl haloperidol (F2), previously shown to protect cardiomyocytes subjected to I/R, dose-dependently downregulated H/R-induced ROS generation, MAPK activation, and Egr-1 expression and activity in CMECs, whereas XO/HX and MAPK activators (EGF, anisomycin) antagonized the effects of F2. Inhibition of the ROS/MAPK/Egr-1 signaling pathway, by either F2, NAC, or inhibition of MAPK, increased CMEC viability and the GSH/GSSG ratio, and decreased Egr-1 nuclear translocation. These results show that the ROS/MAPK/Egr-1 signaling pathway mediates H/R injury in CMECs, and F2 blocks this pathway to protect against H/R injury and further alleviate myocardial I/R injury.

Hyperuricemic nephropathy (HN) is a common clinical complication of hyperuricemia. The pathogenesis of HN is directly related to urea metabolism in the gut microbiota. Febuxostat, a potent xanthine oxidase inhibitor, is the first-line drug used for the treatment of hyperuricemia. However, there have been few studies on the pharmacokinetics of febuxostat in HN animal models or in patients. In this study, a high-purine diet-induced HN rat model was established. The pharmacokinetics of febuxostat in HN rats was evaluated using LC-MS/MS. Astragaloside IV (AST) was used to correct the abnormal pharmacokinetics of febuxostat. Gut microbiota diversity analysis was used to evaluate the effect of AST on gut microbiota. The results showed that the delayed elimination of febuxostat caused drug accumulation after multiple administrations. Oral but not i. p. AST improved the pharmacokinetics of febuxostat in HN rats. The mechanistic study showed that AST could regulate urea metabolism in faeces and attenuate urea-ammonia liver-intestine circulation. Urease-related genera, including Eubacterium, Parabacteroides, Ruminococcus, and Clostridia, decreased after AST prevention. In addition, the decrease in pathogenic genera and increase in short-chain fatty acids (SCFA) producing genera also contribute to renal function recovery. In summary, AST improved the pharmacokinetics of febuxostat in HN rats by comprehensive regulation of the gut microbiota, including urea metabolism, anti-calcification, and short-chain fatty acid generation. These results imply that febuxostat might accumulate in HN patients, and AST could reverse the accumulation through gut microbiota regulation.

Hyperuricemia is an independent risk factor for renal damage and promotes the progression of chronic kidney disease. In this study, we investigated the effect of I-BET151, a small-molecule inhibitor targeting the bromodomain and extraterminal (BET) proteins, on the development of hyperuricemic nephropathy (HN), and the mechanisms involved. Expression levels of bromodomain-containing protein 2 and 4, but not 3 were increased in the kidney of rats with HN; administration of I-BET151 effectively prevented renal dysfunction, decreased urine microalbumin, and attenuated renal fibrosis as indicated by reduced activation of renal interstitial fibroblasts and expression of fibronectin and collagen I in HN rats. Mechanistic studies show that I-BET151 treatment inhibited transition of renal epithelial cells to a mesenchymal cell type as evidenced by preservation of E-cadherin and reduction of vimentin expression. This was coincident with reduced expression of TGF-β1 and dephosphorylation of Smad3 and ERK1/2. I-BET151 was also effective in inhibiting phosphorylation of NF-κB, expression of multiple cytokines and chemokines, and infiltration of macrophages to the injured kidney. Although there were increased serum levels of uric acid and xanthine oxidase, an enzyme that catalyzes production of uric acid, and decreased expression of renal organic anion transporter 1 and 3 that promote urate excretion in the model of HN, and reduced expression levels of urine uric acid, I-BET151 treatment did not affect these responses. Collectively, our results indicate that I-BET151 alleviates HN by inhibiting epithelial to mesenchymal transition and inflammation in association with blockade of TGF-β, ERK1/2 and NF-κB signaling.

Background: The prevalence of hyperuricemia is considered high worldwide. Hyperuricemia occurs due to decreased excretion of uric acid, increased synthesis of uric acid, or a combination of both mechanisms. There is growing evidence that hyperuricemia is associated with a decline of renal function. Purpose: This study is aimed at investigating the effects of the novel compound on lowering the serum uric acid level and alleviating renal inflammation induced by high uric acid in hyperuricemic mice. Methods: Hyperuricemic mice model was induced by potassium oxonate and used to evaluate the effects of the novel compound named FxUD. Enzyme-linked immunosorbent assay was used to detect the related biochemical markers. Hematoxylin-eosin (HE) staining was applied to observe pathological changes. The mRNA expression levels were tested by qRT-PCR. The protein levels were determined by Western blot. In parallel, human proximal renal tubular epithelial cells (HK-2) derived from normal kidney was used to further validate the anti-inflammatory effects in vitro. Results: FxUD administration significantly decreased serum uric acid levels, restored the kidney function parameters, and improved the renal pathological injury. Meanwhile, treatment with FxUD effectively inhibited serum and liver xanthine oxidase (XOD) levels. Reversed expression alterations of renal inflammatory cytokines, urate transporter 1 (URAT1) and glucose transporter 9 (GLUT9) were observed in hyperuricemic mice. Western blot results illustrated FxUD down-regulated protein levels of inflammasome components. Further studies showed that FxUD inhibited the activation of NF-κB signaling pathway in the kidney of hyperuricemic mice. In parallel, the anti-inflammatory effect of FxUD was also confirmed in HK-2. Conclusion: Our study reveals that FxUD exhibits the anti-hyperuricemic and anti-inflammatory effects through regulating hepatic XOD and renal urate reabsorption transporters, and suppressing NF-κB/NLRP3 pathway in hyperuricemia. The results provide the evidence that FxUD may be potential for the treatment of hyperuricemia with kidney inflammation.

Sonneratia apetala Buch-Ham., an exotic mangrove species with antidiabetic, antibacterial, and antioxidant capacities, mainly distributes in the southeast coastal areas in China. The present work investigated the protective effects of Sonneratia apetala leaves and branches extraction (SAL) on hyperuricemia (HUA) in mice. Potassium oxonate (PO) and hypoxanthine (HX) were used to establish the HUA model by challenge for consecutive 7 days. Results revealed that SAL inhibited the increases in kidney weight and index compared to the vehicle group. Meanwhile, SAL significantly decreased the levels of uric acid (UA), creatinine (CRE), and blood urea nitrogen (BUN) in serum. Additionally, SAL inhibited the activity of xanthine oxidase (XOD) in the liver. SAL ameliorated PO- and HX-induced histopathological changes. Moreover, it regulated oxidative stress markers including malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD) activity, and glutathione (GSH) content. Also, SAL inhibited the increases in renal levels of interleukin-6 (IL-6), interleukin-18 (IL-18), interleukin-1β (IL-1β), tumor necrosis factor (TNF-α), monocyte chemotactic protein 1 (MCP-1), and transforming growth factor-β (TGF-β). SAL remarkably reduced suppressor of cytokine signaling 3 (SOCS3), Janus kinase 2 (JAK2), and subsequent phosphorylation of signal transducer and activator of transcription 3 (STAT3) expression. In addition, SAL inhibited the activation of nuclear factor kappa-B (NF-κB) in the kidney. Furthermore, SAL protected against HUA by regulating renal UA transporters of organic anion transporter (OAT1), urate reabsorption transporter 1 (URAT1), and glucose transporter 9 (GLUT9). These findings suggested that SAL ameliorated HUA by inhibiting the production of uric acid and enhancing renal urate excretion, which are related to oxidative stress and inflammation, and the possible molecular mechanisms include its ability to inhibit the JAK/STAT signaling pathway. Thus, SAL might be developed into a promising agent for HUA treatments.

Andrographis paniculata (Burm.f.) Nees has been found to have anti-inflammatory and immunostimulatory effects. This study was to investigate antihyperuricemic and anti-inflammatory effects of A. paniculata leaf extracts. Andrographolide, 14-deoxy-11,12-didehydroandrographolide, and neoandrographolide were quantified in 80% ethanol (EtOH80) and water extracts using High Performance Liquid Chromatography (HPLC) analysis. Antihyperuricemic activity was evaluated using a spectrophotometric in vitro inhibitory xanthine oxidase (XO) assay. The most active extract and andrographolide were further investigated in a hyperuricemic rat model induced by potassium oxonate to determine serum uric acid levels, liver XO activity, followed by Western blot analysis for renal urate transporter URAT1, GLUT9, and OAT1 to investigate the excretion of uric acid via kidney. Anti-inflammatory activity was assessed by in vitro interleukin assay for interleukin (IL-1α, IL-1β, IL-6, IL-8), and tumor necrosis factor (TNF-α) in monosodium urate (MSU) crystal-induced human fibroblast-like synoviocyte (HFLS) cells using ELISA-kits, followed by Western blot analysis for the expression of MyD88, NLRP3, NF-κB p65, and caspase-1 proteins to investigate the inflammation pathway. In vivo assay of the most active extract and andrographolide were performed based on the swelling rate and inhibition of pro-inflammatory mediator release from synovial fluid of a rat knee joint induced by MSU crystals. The results showed that the EtOH80 extract had a greater amount of andrographolide (11.34% w/w) than the water extract (1.38% w/w). In the XO inhibitory activity, none of the samples exhibited greater than 50% inhibition. However, in a rat model, EtOH80 extract (200 mg/kg/day) and andrographolide (30 mg/kg/day) decreased serum uric acid levels and reduced liver XO activity, reduced the protein expression levels of URAT1 and GLUT9, and restored the decrease in OAT1 levels. In the in vitro anti-inflammatory study, EtOH80 extract and andrographolide significantly decreased production of IL-1α, IL-1β, IL-6, and TNF-α, as well as inhibited the synthesis of MyD88, NLRP3, NF-κB p65, and caspase-1 in a concentration-dependent manner, almost comparable to dexamethasone. The EtOH80 extract (200 mg/kg/day) and andrographolide (30 mg/kg) significantly decreased swelling rate and IL-1α, IL-1β, IL-6, and TNF-α in the synovial fluid of rat models in a time-dependent manner, comparable to indomethacin (3 mg/kg/day). In conclusion, the findings show that EtOH80 extract has a substantial anti-gout effect by lowering uric acid levels and suppressing pro-inflammatory mediator production due to the andrographolide content, that might be beneficial in the treatment of gouty-inflammation.

Marantodes pumilum (Primulaceae) has been used in Malaysian folk medicine to help women regain strength after delivery and for "sickness in the bones." It was previously revealed that its extracts inhibited xanthine oxidase (XO) activity in vitro. The leaves and roots of M. pumilum var. alata (MPA), var. pumila (MPP), and var. lanceolata (MPL) were individually extracted in ethanol (80%). The anti-hyperuricemic activity was initially assessed by XO inhibition with a spectrophotometric in vitro assay. The most active extract was further investigated on hyperuricemic rat model induced by potassium oxonate to determine serum uric acid levels and liver XO effect. The in vitro anti-inflammatory activity was carried out on monosodium urate (MSU) crystal-induced pro-inflammatory cytokines (i.e., interleukin (IL)1α, IL-1β, IL-6, IL-8, and tumor necrosis factor (TNF)-α) secretion using human peripheral blood mononuclear cells and ELISA technique, and prostaglandin E2 (PGE2)secretion using radioimmunoassay. The active extract was then investigated on gout-induced inflammation with MSU crystals to determine pro-inflammatory cytokines and PGE2 secretion levels in the synovial fluid of rat knee joint. Quantitative analysis using validated HPLC was performed on the extracts to determine presence of bioactive flavonoids. The findings revealed that extract of MPP leaves gave the highest inhibitory activity on XO (IC50 130.5 μg/mL) compared to other extracts tested. However, all extracts possessed significantly lower activity compared to allopurinol (IC50 0.13 μg/mL). Oral administration of MPP leaf extract (200 mg/kg) significantly reduced serum uric acid level in hyperuricemic rats in time-dependent manner to the baseline level and it was as effective as allopurinol (5 mg/kg). The extract also inhibited liver XO activity (25%) compared to allopurinol (45%). In vitro anti-inflammatory assay showed that extract of MPP roots inhibited MSU crystals-induced secretion of IL-1α, IL-1β, IL-8, TNF-α, and PGE2 with IC50 values of 36, 25, 38, 18, and 46 μg/mL, respectively. Oral administration of the MPP root extract (200 mg/kg) significantly decreased IL-1α, IL-1β, IL-6, TNF-α, and PGE2 levels in rat's synovial fluid as effective as indomethacin. There were no significant body weight changes of all experimental animals. MPP extracts showed presence of myricetin, quercetin and kaempferol. Myricetin was detected with values of 0.2 and 0.6 mg/g for root and leaf extracts, respectively. The anti-hyperuricemic of MPP leaf and anti-inflammatory of MPP root indicated that MPP may be promising for complementary therapy of gout.