Therapeutic voyage of synthetic and natural xanthine oxidase inhibitors

Xanthine oxidase (XO) inhibitors are commonly used to treat gout, nephropathy, and renal stone diseases related to hyperuricemia. However, recent research has shown that these inhibitors may also have potential benefits in preventing vascular diseases, including those affecting the cerebrovasculature. This is due to emerging evidence suggesting that serum uric acid is involved in the growth of cardiovascular disease, and XO inhibition can reduce oxidative stress in the vasculature. There is a great interest in the development of new XO inhibitors for the treatment of hyperuricemia and gout. The present review discusses the many synthetic and natural XO inhibitors that have been developed which are found to have greater potency.     

华山松松节的化学成分及黄嘌呤氧化酶抑制活性研究

目的：研究华山松松节的化学成分和黄嘌呤氧化酶抑制活性。方法通过各种柱色谱方法分离化合物,通过理化性质和波谱数据进行结构鉴定,对提取物和分离得到的化合物通过紫外分光光度法测定黄嘌呤氧化酶抑制活性。结果从松节提取物的石油醚部分共分离得到8个化合物,分别鉴定为异海松-7-烯-18-酸（1）,唐松酸（2）,3β,21α-二甲氧基锯齿石松-14-烯（3）,3β-甲氧基-21α-乙酰氧基-锯齿石松-14-烯（4）,3-甲氧基-锯齿石松-14-烯-21-酮（5）,β-谷甾醇（6）,胆甾醇肉豆蔻酸酯（7）和山嵛酸（8）。结论化合物3为首次从该植物中分离得到,并首次报道了该化合物的碳谱数据;化合物1和2具有一定的黄嘌呤氧化酶抑制作用。     

染料木素等5种黄酮类物质对小鼠血清尿酸水平及黄嘌呤氧化酶活性的影响

目的探讨黄酮类化合物染料木素、芹菜素、槲皮素、芦丁和落新妇苷体外对黄嘌呤氧化酶活性的影响,对正常小鼠血清和肝脏黄嘌呤氧化酶活性的影响,同时评价对小鼠血清尿酸水平的作用。方法采用改良的紫外分光光度法测定染料木素、芹菜素、槲皮素、芦丁和落新妇苷体外对黄嘌呤氧化酶的抑制作用,采用分光光度法研究对小鼠血清和肝脏黄嘌呤氧化酶活性的影响,以磷钨酸法测定对小鼠血清尿酸水平的作用。结果体外实验表明黄酮类化合物染料木素、芹菜素、槲皮素、芦丁和落新妇苷体外对黄嘌呤氧化酶活性无明显影响。体内实验观察到这5种黄酮类化合物能够显著升高或降低黄嘌呤氧化酶的活性;而且,血清尿酸水平与血清黄嘌呤氧化酶活性密切相关,与肝脏黄嘌呤氧化酶活性无明显关联。用这些黄酮类化合物给药的小鼠血清尿酸水平都高于正常对照组。结论这5种黄酮类化合物不能够作为替代别嘌醇的药物用来降低血清尿酸水平。     

痛风颗粒各部位对高尿酸血症大鼠尿酸和黄嘌呤氧化酶活性的影响

目的 通过观察痛风颗粒各部位对高尿酸血症大鼠血尿酸、尿尿酸、血黄嘌呤氧化酶活性和肝脏黄嘌呤氧化酶活性的影响,探讨其治疗痛风的物质基础和机制.方法 以腺嘌呤合乙胺丁醇法诱导大鼠高尿酸血症模型,分别用磷钨酸法和酶比色法检测尿酸和黄嘌呤氧化酶的含量.结果 黄酮类成分在降尿酸和抑制黄嘌呤氧化酶活性上均起主要作用;生物碱类成分对尿中尿酸的排泄和血清黄嘌呤氧化酶活性的抑制起较重要作用,有机酸类成分均未表现出明显作用;全方和有效部位组合有明显的降尿酸和抑制黄嘌呤氧化酶活性的作用.结论 黄酮类、生物碱和有机酸类有效部位组合后的药效与处方药一致,是该处方的有效部位群,对高尿酸血症模型大鼠表现出的降尿酸和抑制黄嘌呤氧化酶活性的作用最为显著.     

丹参二萜醌对黄嘌呤氧化酶活性的抑制作用(英文)

目的黄嘌呤氧化酶(XOD)抑制剂对痛风或其他XOD诱导的疾病有潜在的治疗作用,因此探讨了从丹参(Salvia miltiorrhiza Bge.)中分离的丹参二萜醌---隐丹参酮(CT)和次甲丹参酮(MT)对XOD的抑制作用。方法在分子氧存在的条件下,XOD催化黄嘌呤产生尿酸和超氧阴离子。在黄嘌呤/XOD的反应媒介中加入CT或MT,通过测量波长290nm处吸光度的增加测定尿酸形成速率。结果CT和MT对XOD有抑制作用,酶动力学曲线Dixon图显示抑制方式是竞争型。CT和MT的Ki值分别为17.8和25.9μmol.L-1,抑制活性与浓度正相关。CT和MT的IC50值分别为70和67μmol.L-1,阳性对照别黄嘌呤醇的IC50值为60μmol.L-1。结论CT和MT对XOD活性有抑制作用,对痛风或其他XOD诱导的疾病可能有一定的治疗作用。     

拟黑多刺蚁乙醇提取物中降低小鼠血清尿酸水平活性部位的筛选与化学成分分析

目的研究拟黑多刺蚁乙醇提取物(EEPR)中降低高尿酸血症模型小鼠血清尿酸水平的活性部位及其主要化学成分。方法昆明小鼠分别ig给予别嘌醇0.04 g.kg-1(阳性对照),EEPR 0.128,0.256和0.512 g.kg-1,EEPR的石油醚部位0.079和0.158 g.kg-1,乙酸乙酯部位0.051和0.102 g.kg-1,正丁醇部位0.052和0.104 g.kg-1和水部位0.042和0.084 g.kg-1,每天1次,连续12 d。正常对照组和模型对照组ig给予等体积含0.3%吐温-80的水溶液。末次给药1 h后除正常对照组外,其余各组小鼠均ip给予次黄嘌呤0.6 g.kg-1。1 h后眼眶静脉丛取血,用磷钨酸比色法测定血清尿酸水平,酶比色法测定黄嘌呤氧化酶活性。对降低血清尿酸水平的活性部位进行GC-MS分析,鉴定其主要化学成分。结果高尿酸血症模型小鼠血清尿酸水平与正常对照组比较明显升高(P<0.01),别嘌醇0.04 g.kg-1,EEPR 0.256和0.512 g.kg-1可明显降低该模型小鼠血清尿酸水平(P<0.05),分别由模型组的(464±143)μmol.L-1下降到273±80,346±85和(302±72)μmo.l L-1(P<0.05)。EEPR中石油醚部位0.079和0.158 g.kg-1可显著降低该模型小鼠血清尿酸水平,分别由模型组的(446±139)μmo.lL-1下降到328±100和(314±112)μmol.L-1(P<0.05),其他部位各剂量组对血清尿酸水平均无明显影响。石油醚部位0.158 g.kg-1可明显抑制黄嘌呤氧化酶活性,由模型对照组的(18±8)U.L-1下降到(11±5)U.L-1(P<0.05)。GC-MS分析结果表明,石油醚部位的脂肪酸中,反式十八碳烯酸甲酯占60.77%,十六烷酸甲酯占18.99%,十六碳烯酸甲酯占9.31%。结论 EEPR中石油醚部位可降低高尿酸血症模型小鼠血清尿酸水平,不饱和脂肪酸为石油醚部位脂肪酸的主要成分。     

Isolation and characterization of xanthine oxidase inhibitory constituents of Pyrenacantha staudtii

Six compounds have been isolated from the leaves of Pyrenacantha staudtii, two of which are new compounds.  The new compounds have been characterized as kaempherol 3-O-β-rhamnopyranosyl (1®6)- β-D-glucopyranoside (1) and 4-β-glucopyranosyl-(2-furyl)-5-methy-l,2-glucopyranoside phenylmethanone (2).  The known compounds are 3-pyridinecarboxylic acid (3), β-sitosterol (4), sitosterol 3-O-β-glucopyranoside (5) and taraxerol (6).  Their structures were determined by spectroscopic and chemical evidences.  The two new compounds together with 3-pyridinecarboxylic acid showed significant in vitro xanthine oxidase inhibitory activity.  To the best of our knowledge, this is the first report of these compounds from this plant.
     

A highly sensitive assay for xanthine oxidoreductase activity using a combination of [13C2,15N2]xanthine and liquid chromatography/triple quadrupole mass spectrometry

In this study, we developed a highly sensitive assay for xanthine oxidoreductase (XOR) activity utilizing a combination of [¹³C₂,¹⁵N₂]xanthine and liquid chromatography (LC)/triple quadrupole mass spectrometry (TQMS). In this assay, the amount of [¹³C₂,¹⁵N₂]uric acid (UA) produced by XOR was determined by using LC/TQMS. For this assay, we synthesized [¹³C₂,¹⁵N₂]xanthine as a substrate, [¹³C₂,¹⁵N₂]UA as an analytical standard, and [¹³C₃,¹⁵N₃]UA as an internal standard. The [¹³C₂,¹⁵N₂]UA calibration curve obtained using LC/TQMS under the selected reaction monitoring mode was evaluated, and the results indicated good linearity (R² = 0.998, weighting of 1/x²) in the range of 20 to 4000 nM. As a model reaction of less active samples, the XOR activity of serial‐diluted mouse plasma was measured. Thereby, the XOR activity of the 1024‐fold‐diluted mouse plasma was 4.49 ± 0.44 pmol/100 μL/h (mean ± standard deviation, n = 3). This value is comparable to the predicted XOR activity value of healthy human plasma. Hence, this combination method may be used to obtain high‐sensitivity measurements required for XOR activity analysis on various organs or human plasma.     

高尿酸血症的发病机制与药物治疗研究进展

高尿酸血症是由于嘌呤代谢紊乱使尿酸生成增多和（或）排泄减少所致的代谢性疾病。高尿酸血症不仅是引起痛风的重要生化基础,而且与高血压、高脂血症、动脉粥样硬化、肥胖、胰岛素抵抗的发生密切相关。因此,针对其发病机制和药物治疗的研究已成为关注热点。本文阐述了高尿酸血症的发病机制,并从抑制尿酸合成与促进尿酸排泄两个方面介绍了相关药物治疗的研究进展。     

Design,synthesis, and molecular docking studies of N‐(9,10‐anthraquinone‐2‐carbonyl)amino acid derivatives as xanthine oxidase inhibitors

A series of N‐(9,10‐anthraquinone‐2‐carbonyl)amino acid derivatives ( 1a–j ) was designed and synthesized as novel xanthine oxidase inhibitors. Among them, the L/D‐phenylalanine derivatives ( 1d and 1i ) and the L/D‐tryptophan derivatives ( 1e and 1j ) were effective with micromolar level potency. In particular, the L‐phenylalanine derivative 1d (IC₅₀ = 3.0 μm ) and the D‐phenylalanine derivative 1i (IC₅₀ = 2.9 μm ) presented the highest potency and were both more potent than the positive control allopurinol (IC₅₀ = 8.1 μm ). Preliminary SAR analysis pointed that an aromatic amino acid fragment, for example, phenylalanine or tryptophan, was essential for the inhibition; the D‐amino acid derivative presented equal or greater potency compared to its L‐enantiomer; and the 9,10‐anthraquinone moiety was welcome for the inhibition. Molecular simulations provided rational binding models for compounds 1d and 1i in the xanthine oxidase active pocket. As a result, compounds 1d and 1i could be promising lead compounds for further investigation.     

以黄嘌呤氧化酶为靶点的新型非嘌呤类抗痛风及高尿酸血症药物研究进展

黄嘌呤氧化酶（XO）催化黄嘌呤生成尿酸及次黄嘌呤生成黄嘌呤的过程,是抗高尿酸血症或痛风药物研究的关键靶点。黄嘌呤氧化酶抑制剂由于作用机制明确、疗效显著而倍受关注,研发新型XO抑制剂具有广阔的应用前景。XO的结构生物学及分子模拟技术为新一代非嘌呤类XO抑制剂的合理药物设计奠定了基础。本文综述了以黄嘌呤氧化酶为靶标的新型非嘌呤类小分子杂环化合物及天然产物来源的活性分子在抗高尿酸血症或痛风药物研究领域中的进展。     

Evaluating the urate-lowering effects of different microbial fermented extracts in hyperuricemic models accompanied with a safety study

Uric acid (UA) is an end product of purine metabolism by the enzyme xanthine oxidase (XOD). Hyperuricemia is characterized by the accumulation of serum UA and is an important risk factor for gout and many chronic disorders. XOD inhibitors or uricase (catalyzes UA to the more soluble end product) can prevent these chronic diseases. However, currently available hypouricemic agents induce severe side effects. Therefore, we developed new microbial fermented extracts (MFEs) with substantial XOD inhibition activity from Lactobacillus (MFE-21) and Acetobacter (MFE-25), and MFE-120 with high uricase activity from Aspergillus. The urate-lowering effects and safety of these MFEs were evaluated. Our results showed that MFE-25 exerts superior urate-lowering effects in the therapeutic model. In the preventive model, both MFE-120 and MFE-25 significantly reduced UA. The results of the safety study showed that no organ toxicity and no treatment-related adverse effects were observed in mice treated with high doses of MFEs. Taken together, the results showed the effectiveness of MFEs in reducing hyperuricemia without systemic toxicity in mice at high doses, suggesting that they are safe for use in the treatment and prevention of hyperuricemia.     

Hypouricaemic action of mangiferin results from metabolite norathyriol via inhibiting xanthine oxidase activity

Context Mangiferin has been reported to possess a potential hypouricaemic effect. However, the pharmacokinetic studies in rats showed that its oral bioavailability was only 1.2%, suggesting that mangiferin metabolites might exert the action.

Objective The hypouricaemic effect and the xanthine oxidase inhibition of mangiferin and norathyriol, a mangiferin metabolite, were investigated. Inhibition of norathyriol analogues (compounds 3–9) toward xanthine oxidase was also evaluated.

Materials and methods For a dose-dependent study, mangiferin (1.5–6.0?mg/kg) and norathyriol (0.92–3.7?mg/kg) were administered intragastrically to mice twice daily for five times. For a time-course study, mice received mangiferin and norathyriol both at a single dose of 7.1?μmol/kg. In vitro, inhibition of test compounds (2.4–2.4?mM) against xanthine oxidase activity was evaluated by the spectrophotometrical method. The inhibition type was identified from Lineweaver–Burk plots.

Results Norathyriol (0.92, 1.85 and 3.7?mg/kg) dose dependently decreased the serum urate levels by 27.0, 33.6 and 37.4%, respectively. The action was more potent than that of mangiferin at the low dose, but was equivalent at the higher doses. Additionally, the hypouricaemic action of them exhibited a time dependence. In vitro, norathyriol markedly inhibited the xanthine oxidase activities, with the IC₅₀ value of 44.6?μM, but mangiferin did not. The kinetic studies showed that norathyriol was an uncompetitive inhibitor by Lineweaver–Burk plots. The structure–activity relationships exhibited that three hydroxyl groups in norathyriol at the C-1, C-3 and C-6 positions were essential for maintaining xanthine oxidase inhibition.

Discussion and conclusion Norathyriol was responsible for the hypouricaemic effect of mangiferin via inhibiting xanthine oxidase activity.     

A method for determination of the inhibition of xanthine oxidase activity in plasma during allopurinol treatment

Summary A micromethod suitable for measuring the combined blood levels of allopurinol and alloxanthine has been developed. The two compounds display marked inhibition of xanthine oxidase activity (K_i=6.3×10^–10 and 5.4×10^–10 M), so the amounts found in 20 µl serum from allopurinol-treated patients can cause marked inhibition of xanthine oxidase activity in vitro under appropriate conditions. If the concentrations of compounds acting in an allopurinol-like manner are expressed in terms of allopurinol, activity equivalent values are obtained which reflect the effective drug concentration during therapy. The procedure is simple and suitable for serial examinations. It also satisfies the demands of the clinician, in that it can reveal any disturbance in the absorption of allopurinol and in excretion of the drug and its active metabolite, alloxanthine.     

The effect of allopurinol on the cerebral vasculature of patients with subcortical stroke; a randomized trial

AIMS

New preventative strategies for stroke are required. One promising strategy is uric acid reduction and xanthine oxidase inhibition with allopurinol. We sought to investigate whether allopurinol improves cerebrovascular reactivity (CVR) following subcortical stroke.

METHODS

We performed a randomized, double-blind, controlled study to investigate the effect of a 3-month course of 300 mg allopurinol once daily vs. placebo on CVR in individuals with recent (within 6 months) subcortical stroke. Participants were randomized on a 1 : 1 basis. CVR was defined as the percentage change in middle cerebral artery flow velocity following an intravenous injection of 15 mg kg⁻¹ of acetazolamide. Our primary end-point was the CVR difference between baseline and 3 months. Secondary end-points included measures of peripheral vascular reactivity and blood markers of inflammation and endothelial activation.

RESULTS

We enrolled 50 participants; 45 completed the protocol. Baseline serum urate was 0.35 mmol l⁻¹ (SD 0.1) and 0.34 mmol l⁻¹ (SD 0.1) in the allopurinol and placebo groups, respectively. There were no serious adverse events related to treatment. CVR did not change following treatment with allopurinol [median CVR change 0.89% after allopurinol (n= 20) and −0.68% after placebo (n= 25); 95% confidence interval for estimated difference in medians −13.4, 25.5, P= 0.64]. Urate was significantly lowered by allopurinol but no change in other secondary end-points was seen.

CONCLUSION

Xanthine oxidase inhibition with allopurinol has previously been shown to improve cerebrovascular function, but no benefit was seen in this study. It may therefore be that previous encouraging findings will not translate into important clinical benefits.     

几种虫草无性型及其相关真菌体外抑制单胺氧化酶活性研究

目的选择较强抑制单胺氧化酶(MAO)活性的菌株及初步确定活性部位。方法基于消耗底物犬尿胺原理,应用分光光度计对20个菌株进行初筛,在此基础上用酶标仪对10株细脚拟青霉进行比较研究,并由相对抑制率初步确定活性部位。结果RCEF1054、RCEF0943、RCEF1078和RCEF0440菌株活性较强。细脚拟青霉菌丝体不同溶剂先后提取所得产物MAO抑制率不同,氯仿组>甲醇组>水提组。氯仿组抑制率最高的菌株是Pt25(63.66%)。甲醇和水提物活性较低。10个菌株发酵液提取物均有一定活性,抑制率在15.5%~31.7%之间,较高的是pt12、pt02和pt57菌株。结论不同菌种或不同溶剂提取物的抑制MAO活性差异显著。细脚拟青霉RCEF0788(pt57)菌株提取物具有较高活性。     

Febuxostat: A Novel Agent for Management of Hyperuricemia in Gout

Gout is a metabolic disorder characterized by elevated uric acid levels in the body, associated with painful arthritis, tophi and nephropathy. The most frequently used pharmacologic urate lowering strategies involve reducing urate production with a xanthine oxidase inhibitor and enhancing urinary excretion of uric acid with a uricosuric agent. Urate lowering agents are limited in number, availability and effectiveness. The emergence of a new medication, febuxostat, to lower serum urate levels is welcome as no new drug have been approved since the introduction of allopurinol, in 1964, and the drugs that are available have limitations owing to inefficacy or toxicity. Febuxostat is a novel, nonpurine selective inhibitor of xanthine oxidase, is a potential alternative to allopurinol for patients with hyperuricemia and gout.     

2-苯基-5-吡啶基-1,3,4-噁二唑类化合物的合成及黄嘌呤氧化酶抑制活性

目的 设计合成2-苯基-5-吡啶基-1,3,4-噁二唑类化合物,并对其黄嘌呤氧化酶抑制活性进行初步评价。方法 以对羟基苯甲酸甲酯为原料,经烃化、肼解、环合等反应合成目标化合物。以非布司他为阳性对照药,采用牛源的黄嘌呤氧化酶对目标化合物的抑制活性进行评价。结果 共合成了15 个未见文献报道的目标化合物,结构经核磁共振氢谱、飞行时间质谱和红外光谱确证。目标化合物均表现出一定的黄嘌呤氧化酶抑制活性,其中化合物 4m（IC₅₀=1.04 µmol·L^-1）活性最好,但低于阳性对照药非布司他（IC₅₀=0.024 µmol·L^-1）。结论 2-苯基-5-吡啶基-1,3,4-噁二唑类化合物作为新型黄嘌呤氧化酶抑制剂,其构效关系值得进一步研究。