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1.
Inhibition of xanthine oxidase-catalyzed conversion of xanthine to uric acid by various pyrazolopyrimidine-based inhibitors (allopurinol derivatives) was evaluated and compared with the standard inhibitor allopurinol. Three compounds out of the seven compounds used in the study were found to be reasonably good inhibitors of xanthine oxidase (XO). 4-Amino-6-mercaptopyrazolo-3,4-d-pyrimidine was found to be the most potent inhibitor of XO (IC50 = 0.600 +/- 0.009 microM). 4-Mercapto-1H-pyrazolo-3,4-d-pyrimidine (IC50 = 1.326 +/- 0.013 microM) and 4-amino-6-hydroxypyrazolo-3,4-d-pyrimidine (IC50 = 1.564 +/- 0.065 microM) also showed comparable inhibitory activity to that of allopurinol (IC50 = 0.776 +/- 0.012 microM). All three compounds showed competitive type of inhibition with comparable Ki values. Induction of the electron transfer reaction catalyzed by XO in the presence of these compounds monitored as reduction of 2,6-dichlorophenolindophenol (DCPIP) revealed that electron transfer by 4-amino-6-mercaptopyrazolo-3,4-d-pyrimidine is comparable to that obtained by allopurinol or xanthine. However, 4-mercapto-1H-pyrazolo-3,4-d-pyrimidine and 4-amino-6-hydroxypyrazolo-3,4-d-pyrimidine did not show DCPIP reduction. On the other hand, enzymatic reduction of cytochrome c in the presence of the three compounds was found to be insignificant and much less in comparison to allopurinol and xanthine. Therefore, both 4-amino-6-hydroxypyrazolo-3,4-d-pyrimidine and 4-mercapto-1H-pyrazolo-3,4-d-pyrimidine displayed the inhibitory property and also did not produce XO-mediated reactive oxygen species (ROS). Since 4-mercapto-1H-pyrazolo-3,4-d-pyrimidine was found to have some toxicity, the effect of 4-amino-6-hydroxypyrazolo-3,4-d-pyrimidine on the enzymatic formation of uric acid and ROS was investigated and it was found that this compound was inhibiting enzymatic generation of both uric acid and ROS. It can be noted that the standard inhibitor, allopurinol, inhibits uric acid formation but produces ROS.  相似文献   

2.
Xanthine oxidase (XO) is responsible for the pathological condition called gout. Inhibition of XO activity by various pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidine-4-one derivatives was assessed and compared with the standard inhibitor allopurinol. Out of 10 synthesized compounds, two compounds, viz. 3-amino-6-(2-hydroxyphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one (3b) and 3-amino-6-(4-chloro-2-hydroxy-5-methylphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one (3g) were found to have promising XO inhibitory activity of the same order as allopurinol. Both compounds and allopurinol inhibited competitively with comparable Ki (3b: 3.56?µg, 3g: 2.337?µg, allopurinol: 1.816?µg) and IC50 (3b: 4.228?µg, 3g: 3.1?µg, allopurinol: 2.9?µg) values. The enzyme–ligand interaction was studied by molecular docking using Autodock in BioMed Cache V. 6.1 software. The results revealed a significant dock score for 3b (?84.976?kcal/mol) and 3g (?90.921?kcal/mol) compared with allopurinol (?55.01?kcal/mol). The physiochemical properties and toxicity of the compounds were determined in silico using online computational tools. Overall, in vitro and in silico study revealed 3-amino-6-(4-chloro-2-hydroxy-5-methylphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2–a]pyrimidin-4-one (3g) as a potential lead compound for the design and development of XO inhibitors.  相似文献   

3.
Xanthine oxidase (XO) is a critical source of reactive oxygen species (ROS) that contribute to vascular inflammation. Binding of XO to vascular endothelial cell glycosaminoglycans (GAGs) results in significant resistance to inhibition by traditional pyrazolopyrimidine-based inhibitors such as allopurinol. Therefore, we compared the extent of XO inhibition (free and GAG-bound) by allopurinol to that by febuxostat, a newly approved nonpurine XO-specific inhibitor. In solution, febuxostat was 1000-fold more potent than allopurinol at inhibiting XO-dependent uric acid formation (IC50 = 1.8 nM vs 2.9 μM). Association of XO with heparin-Sepharose 6B (HS6B-XO) had minimal effect on the inhibition of uric acid formation by febuxostat (IC50 = 4.4 nM) while further limiting the effect of allopurinol (IC50 = 64 μM). Kinetic analysis of febuxostat inhibition revealed Ki values of 0.96 (free) and 0.92 nM (HS6B-XO), confirming equivalent inhibition for both free and GAG-immobilized enzyme. When XO was bound to endothelial cell GAGs, complete enzyme inhibition was observed with 25 nM febuxostat, whereas no more than 80% inhibition was seen with either allopurinol or oxypurinol, even at concentrations above those tolerated clinically. The superior potency for inhibition of endothelium-associated XO is predictive of a significant role for febuxostat in investigating pathological states in which XO-derived ROS are contributive and traditional XO inhibitors are only slightly effective.  相似文献   

4.
The purpose of this study was to evaluate the inhibitory effect of renierol, extracted from marine sponge Halicdona.SP., on xanthine oxidase (XO) and its hypouricemic effect in vivo. Renierol and a positive control, allopurinol, were tested for their effects on XO activity by measuring the formation of uric acid and superoxide radical from xanthine. Renierol inhibited XO in a concentration-dependent and competitive manner. IC50 value was 1.85 μg·ml? 1 through the measuring of uric acid and was 1.36 μg.ml? 1 through the measuring of superoxide radical. Renierol was found to have an in vivo hypouricemic activity against potassium oxonate-induced hyperuricaemia in mice. After oral administration of renierol at doses of 10, 20 and 30 mg.kg? 1, there was a significant decrease in the serum urate level (4.08 ± 0.09 mg.dl? 1, P < 0.01), (3.47 ± 0.11 mg.dl? 1, P < 0.01) and (3.12 ± 0.08 mg.dl? 1, P < 0.01), when compared to the hyperuricaemic control (6.74 ± 0.23 mg.dl? 1). Renierol was a potent XO inhibitor with hypouricemic activity in mice.  相似文献   

5.
Xanthine oxidase (XO) catalyzes the oxidation of hypoxanthine to xanthine and then to uric acid. Excessive production of uric acid leads to hyperuricaemia. Due to the serious side effects of allopurinol, it is an urgent need to explore new XO inhibitors. Herein, the effects of theaflavin (TF1) on XO and anti-hyperuricaemia effect in hyperuricemic mice were investigated. Kinetic analysis indicate that TF1 is a reversible competitive inhibitor and has a significant inhibitory effect on XO with an IC50 value of 63.17 ± 0.13 μmol/L. Analysis of fluorescence spectra suggests that TF1 causes the obvious fluorescence quenching of XO, which is mainly driven by hydrophobic interactions and hydrogen bonds. Docking studies demonstrate that TF1 interacts with dozens of amino acid residues surrounded in the active cavity of XO, including Glu-879, Pro-1012, Thr-1010, Val-1011, Lys-771, Glu-802, Pro-1076, Leu-873, Leu-1014, Asn-768, Leu-648 and Phe-649. The inhibitory mechanism may be the insertion of TF1 into the active site of XO, which hinders the substrate xanthine to enter into the site. Furthermore, the results from animal experiments demonstrate that TF1 is effective in reducing serum uric acid in mice. These findings suggest that TF1 may be a potential drug candidate for the treatment of hyperuricaemia.  相似文献   

6.
The design and synthesis of a series of thirty-two halogenated 1-tetralone or 6-amino-1-tetralone chalcone derivatives was achieved by the Claisen-Schmidt condensation reaction and were evaluated for their inhibitory effects against ROS production in LPS-stimulated RAW 264.7 macrophages. It was observed that the introduction of amino moiety into 1-tetralone skeleton greatly increased the inhibitory potency compared to corresponding 1-tetralone chalcones. Among the synthesized compounds, compound 18 which consists of 6-amino-1-tetralone skeleton together with o-fluorobenzylidene showed the most potent ROS inhibitory effect with IC50 value of 0.25 ± 0.13 µM. SAR analysis revealed that amino moiety at the 6th position of 1-tetralone chalcones have an important role for exerting the greater ROS inhibitory potency in LPS-stimulated RAW 264.7 macrophages than those exhibited by 1-tetralone chalcones alone.  相似文献   

7.
Targeting EGFR has proven to be beneficial in the treatment of several types of solid tumours. So, a series of novel 2-(4-oxo-3-(4-sulfamoylphenyl)-3,4-dihydrobenzo[g]quinazolin-2-ylthio)-N-substituted acetamide 519 were synthesised from the starting material 4-(2-mercapto-4-oxobenzo[g]quinazolin-3(4H)-yl) benzenesulfonamide 4, to be evaluated as dual EGFR/HER2 inhibitors. The target compounds 519, were screened for their cytotoxic activity against A549 lung cancer cell line. The percentage inhibition of EGFR enzyme was measured and compared with erlotinib as the reference drug. Compounds 6, 8, 10, and 16 showed excellent EGFR inhibitory activity and were further selected for screening as dual EGFR/HER2 inhibitors. The four selected compounds showed IC50 ranging from 0.009 to 0.026?µM for EGFR and 0.021 to 0.069?µM for the HER2 enzyme. Compound 8 was found to be the most potent in this study with IC50 0.009 and 0.021?µM for EGFR and HER2, respectively.  相似文献   

8.
A novel series of biscoumarin-1,2,3-triazole hybrids 6a-n was prepared and evaluated for α-glucosidase inhibitory potential. All fourteen derivatives exhibited excellent α-glucosidase inhibitory activity with IC50 values ranging between 13.0 ± 1.5 and 75.5 ± 7.0 µM when compared with the acarbose as standard inhibitor (IC50 = 750.0 ± 12.0 µM). Among the synthesized compounds, compounds 6c (IC50 = 13.0 ± 1.5 µM) and 6g (IC50 = 16.4 ± 1.7 µM) exhibited the highest inhibitory activity against α-glucosidase and were non-cytotoxic towards normal fibroblast cells. Kinetic study revealed that compound 6c inhibits the α-glucosidase in a competitive mode. Furthermore, molecular docking investigation was performed to find interaction modes of the biscoumarin-1,2,3-triazole derivatives.  相似文献   

9.
A series of hydroxychalcone derivatives have been designed, synthesized and evaluated for human xanthine oxidase (XO) inhibitory activity. Most of the tested compounds acted moderate XO inhibition with IC50 values in the micromolar rang. Molecular docking and kinetic studies have been performed to explain the binding modes of XO with the selected compounds. In addition, in vitro antioxidant screening results indicated that some of the hydroxychalcones possessed good anti-free radical activities. Furthermore, the preferred compounds 16 and 18 were able to significantly inhibit hepatic xanthine oxidase activity and reduced serum uric acid level of hyperuricemic mice in vivo. In summary, compounds 16 and 18 with balanced activities of antioxidant, XO inhibition and serum uric acid reduction, which are promising candidates for the treatment of hyperuricemia and gout.  相似文献   

10.
3,4-Dimethoxybenzohydrazide derivatives (1–25) have been synthesized and evaluated for their urease inhibitory potential. Among the series, compounds 2, 3, 4 and 5 with IC50 values 12.61 ± 0.07, 18.24 ± 0.14, 19.22 ± 0.21, and 8.40 ± 0.05 µM, respectively, showed excellent urease inhibitory potentials when compared with standard thiourea (IC50 value 21.40 ± 0.21 µM). Compounds 1, 6, 8, 18, 19 and 20 also showed good to moderate inhibition, while the remaining compounds were found to be completely inactive. The structures of compounds 6 and 25 were confirmed through X-ray crystallography while the structures of remaining compounds were confirmed through ESI-MS and 1H NMR. Molecular docking studies were performed understand the binding interactions with enzyme active site. The synthesized compounds were evaluated for cytotoxicity and found to be nontoxic.  相似文献   

11.
Inhibitory activity of Fe-ion-catalyzed radical oxidation products from 22 types of phenolic compounds toward xanthine oxidase (XO) was investigated. Phenols are readily oxidizable compounds in nature and, thus, showed potent antioxidant activities. Among the phenols screened in this study, noticeable activity was observed in the oxidation product of caffeic acid, whereas almost no XO-inhibitory activity of caffeic acid was observed. Assay-guided purification of the oxidation product of caffeic acid afforded a highly potent XO inhibitor, with an IC50 value that was calculated to be 60 nmol L−1, which indicated XO-inhibitory activity much stronger than that of allopurinol (IC50 = 1 μmol L−1), a potent XO inhibitor and excellent medicine for the treatment of gout. The chemical structure of this new XO inhibitor was investigated by one- and two-dimensional NMR and HR–ESI–MS analyses, and the unique tetracyclic structure was confirmed by synthesis starting from commercially available 1,2,4-trimethoxybenzene and 3,4-dimethoxylbenzoyl chloride.  相似文献   

12.
Arginase performs the first enzymatic step in polyamine biosynthesis in Leishmania and represents a promising target for drug development. Polyamines in Leishmania are involved in trypanothione synthesis, which neutralize the oxidative burst of reactive oxygen species (ROS) and nitric oxide (NO) that are produced by host macrophages to kill the parasite. In an attempt to synthesize arginase inhibitors, six 1-phenyl-1H-pyrazolo[3,4-d]pyrimidine derivatives with different substituents at the 4-position of the phenyl group were synthesized. All compounds were initially tested at 100 µM concentration against Leishmania amazonensis ARG (LaARG), showing inhibitory activity ranging from 36 to 74%. Two compounds, 1 (R=H) and 6 (R=CF3), showed arginase inhibition >70% and IC50 values of 12 µM and 47 µM, respectively. Thus, the kinetics of LaARG inhibition were analyzed for compounds 1 and 6 and revealed that these compounds inhibit the enzyme by an uncompetitive mechanism, showing Kis values, and dissociation constants for ternary complex enzyme-substrate-inhibitor, of 8.5 ± 0.9 µM and 29 ± 5 µM, respectively. Additionally, the molecular docking studies proposed that these two uncompetitive inhibitors interact with different LaARG binding sites, where compound 1 forms more H-bond interactions with the enzyme than compound 6. These compounds showed low activity against L. amazonensis free amastigotes obtained from mice lesions when assayed with as much as 30 µM. The maximum growth inhibition reached was between 20 and 30% after 48 h of incubation. These results suggest that this system can be promising for the design of potential antileishmanial compounds.  相似文献   

13.
The antioxidant potential, antiglycation, and total phenolic content of essential oils (EOs) extracted from 19 medicinal plants were assessed. The variation in yield of the EOs with respect to altitude and season was also studied. The antioxidant potential of Pimenta dioica (L.) Merr., Psiadia terebinthina A.J. Scott, Laurus nobilis L., Piper betle L., and Citrus hystrix DC. showed IC50 values less/equivalent to the positive controls. Weak correlations were observed between the 1,1-diphenyl-2-picryl hydrazyl (DPPH) and xanthine oxidase (XO) assays as well as between the DPPH and nitric oxide radical scavenging (NO) assay and between the XO and 2,2 azinobis (3-ethylbenzothiazoline-6 sulphonic acid (ABTS) assay. Cupressus macrocarpa Hartw., L. nobilis, Cinnamomum zeylanicum Nees, and Psidium guajava L. successfully inhibited in vitro glycated end-products (IC50: 451.53 ± 3.00, 387.04 ± 1.53, 348.59 ± 3.34 and 401.48 ± 2.86 µg/mL respectively) compared to aminoguanidine (IC50: 546.69 ± 3.57 µg/mL). Some of the EOs had a high content of phenolic compounds. EOs such as P. dioica, P. terebinthina, L. nobilis, P. guajava, and C. hystrix were found to be rich in eugenol and other phenolic compounds. The EOs evaluated in the present study may have applications in the nutraceutical and pharmaceutical industries.  相似文献   

14.
Excessive uric acid production, which causes gout and hyperuricemia, can be blocked by inhibiting xanthine oxidase (XO). However, some agents to block on XO often cause side effects, thereby necessitating the identification of new inhibitors. During the screening of XO inhibitors from various mushroom extracts, we found that a methanolic extract of the fruiting bodies of Tyromyces fissilis, an inedible and non-toxic fungus, showed inhibitory activity. Both n-hexane and ethyl acetate layers, obtained by partitioning this extract exhibited XO inhibitory activity. Subsequently, using an activity-guided separation method, eight active compounds (1–8) were isolated. The structures of five of the new compounds, 24, 6, and 7, were elucidated by spectral analysis and chemical derivatization. All compounds had a salicylic acid moiety with an aliphatic group at the C-6 position. Notably, 2-hydroxy-6-pentadecylbenzoic acid (1) showed the highest level of XO noncompetitive inhibition (58.9 ± 2.2% at 25 µM).  相似文献   

15.
Phytochemical investigations were performed on the EtOAc-soluble fraction of the whole plant of the sky flower (Duranta repens) which led to the isolation of the iridoid glycosides 16. Their structures were elucidated by both 1D and 2D NMR spectroscopic analysis. All the compounds showed potent antioxidative scavenging activity in four different tests, with half maximal inhibitory concentration (IC50) values in the range 0.481–0.719?mM against DPPH radicals, 4.07–17.21 µM for the hydroxyl radical (?OH) inhibitory activity test, 43.3–97.37 µM in the total reactive oxygen species (ROS) inhibitory activity test, and 3.39–18.94 µM in the peroxynitrite (ONOO?) scavenging activity test. Duranterectoside A (1) displayed the strongest scavenging potential with IC50 values of (0.481?±?0.06?mM, 4.07?±?0.03, 43.30?±?0.05, 3.39?±?0.02?µM) for the DPPH radicals, ?OH inhibitory activity test, total ROS inhibitory activity test and the ONOO? scavenging activity test, respectively.  相似文献   

16.
Xanthine oxidase (XO) is a key enzyme which can catalyze xanthine to uric acid causing hyperuricemia in humans. By using the fractionation technique and inhibitory activity assay, an active compound that prevents XO from reacting with xanthine was isolated from wheat leaf. It was identified by the Mass and NMR as 6-aminopurine (adenine). A structure-activity study based on 6-aminopurine was conducted. The inhibition of XO activity by 6-aminopurine (IC(50)=10.89+/-0.13 microM) and its analogues was compared with that by allopurinol (IC(50)=7.82+/-0.12 microM). Among these analogues, 2-chloro-6(methylamino)purine (IC(50)=10.19+/-0.10 microM) and 4-aminopyrazolo[3,4-d] pyrimidine (IC(50)=30.26+/-0.23 microM) were found to be potent inhibitors of XO. Kinetics study showed that 2-chloro-6(methylamino)purine is non-competitive, while 4-aminopyrazolo[3,4-d]pyrimidine is competitive against XO.  相似文献   

17.
The M2 isoform of pyruvate kinase (PKM2) is a potential antitumor therapeutic target. In this study, we designed and synthesised a series of 2, 3-didithiocarbamate substituted naphthoquinones as PKM2 inhibitors based on the lead compound 3k that we previously reported. Among them, compound 3f (IC50?=?1.05?±?0.17 µM) and 3h (IC50?=?0.96?±?0.18 µM) exhibited potent inhibition of PKM2, and their inhibitory activities are superior to compound 3k (IC50?=?2.95?±?0.53 µM) and the known PKM2 inhibitor shikonin (IC50?=?8.82?±?2.62 µM). In addition, we evaluated in vitro antiproliferative effects of target compounds using MTS assay. Most target compounds exhibited dose-dependent cytotoxicity with IC50 values in nanomolar concentrations against HCT116, MCF7, Hela, H1299 and B16 cells. These small molecule PKM2 inhibitors not only provide candidate compounds for cancer therapy, but also offer a tool to probe the biological effects of PKM2 inhibition on cancer cells.  相似文献   

18.
A series of 5-substitutedbenzylideneamino-2-butylbenzofuran-3-yl-4-methoxyphenyl methanones is synthesized and evaluated for antileishmanial and antioxidant activities. Compounds 4f (IC50?=?52.0?±?0.09?µg/ml), 4h (IC50?=?56.0?±?0.71?µg/ml) and 4l (IC50?=?59.3?±?0.55?µg/ml) were shown significant antileishmanial when compared with standard sodium stibogluconate (IC50?=?490.0?±?1.5?µg/ml). Antioxidant study revealed that compounds 4i (IC50?=?2.44?±?0.47?µg/ml) and 4l (IC50?=?3.69?±?0.44?µg/ml) have shown potent comparable activity when compared with standard ascorbic acid (IC50?=?3.31?±?0.34?µg/ml). Molecular docking study was carried out which replicating results of biological activity in case of initial hits 4f and 4h suggesting that these compounds have a potential to become lead molecules in drug discovery process. In silico ADME study was performed for predicting pharmacokinetic profile of the synthesised antileishmanial agents and expressed good oral drug like behaviour.  相似文献   

19.
A new series of pyrazolo[3,4-d]pyrimidine-6-one derivatives (2a–2j) were prepared by using the Biginelli multicomponent cyclocondensation of 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one (1a), different aromatic aldehydes, and urea with a catalytic amount of HCl at reflux temperature. These compounds were characterized by IR, 1H NMR, 13C NMR, and Mass spectral data. In vitro antiamoebic activity was performed against HM1:IMSS strain of Entamoeba histolytica. The results showed that the compounds 2b, 2i, and 2j with IC50 values of 0.37 µM, 0.04 µM, and 0.06 µM, respectively, exhibited better antiamoebic activity than the standard drug metronidazole (IC50?=?1.33 µM). The toxicological studies of these compounds on human breast cancer MCF-7 cell line showed that the compounds 2b, 2i, and 2j exhibited >80% viability at the concentration range of 1.56–50 µM.  相似文献   

20.
Propolis is rich in diverse bioactive compounds. Propolis samples were collected from three localities of Cameroon and used in the study. Column chromatography separation of propolis MeOH:DCM (50:50) extracts yielded a new isoflavonol, 2-hydroxy-8-prenylbiochanin A (1) alongside 2′,3′-dihydroxypropyltetraeicosanoate (2) and triacontyl p-coumarate (3) isolated from propolis for first time together with seven compounds: β-amyrine (4), oleanolic acid (5), β-amyrine acetate (6), lupeol (7), betulinic acid (8), lupeol acetate (9) and lupenone (10). These compounds were tested for their inhibitory effect on oxidative burst where intracellular reactive oxygen species (ROS) were produced from zymosan stimulated human whole blood phagocytes and on production of nitric oxide (NO) from lipopolysaccharide (LPS) stimulated J774.2 mouse macrophages. The cytotoxicity of these compounds was evaluated on NIH-3 T3 normal mouse fibroblast cells, antiradical potential on 2,2-diphenyl-1-picrylhydrazylhydrazyl (DPPH·) as well as their anti-yeast potential on four selected candida species. Compound 1 showed higher NO inhibition (IC50 = 23.3 ± 0.3 µg/mL) than standard compound L-NMMA (IC50 = 24.2 ± 0.8 µg/mL). Higher ROS inhibition was shown by compounds 6 (IC50 = 4.3 ± 0.3 µg/mL) and 9 (IC50 = 1.1 ± 0.1 µg/mL) than Ibuprofen (IC50 = 11.2 ± 1.9 µg/mL). Furthermore, compound 1 displayed moderate level of cytotoxicity on NIH-3 T3 cells, with IC50 = 5.8 ± 0.3 µg/mL compared to the cyclohexamide IC50 = 0.13 ± 0.02 µg/mL. Compound 3 showed lower antifungal activity on Candida krusei and Candida glabrata, MIC of 125 μg/mL on each strain compared to 50 μg/mL for fuconazole. The extracts showed low antifungal activities ranging from 250 to 500 μg/mL on C. albicans, C. krusei and C. glabrata and the values of MIC on Candida parapsilosis were 500 μg/mL and above. DPPH* scavenging activity was exhibited by compounds 1 (IC50 = 15.653 ± 0.335 μg/mL) and 3 (IC50 = 89.077 ± 24.875 μg/mL) compared to Vitamin C (IC50 = 3.343 ± 0.271 μg/mL) while extracts showed moderate antiradical activities with IC50 values ranging from 309.31 ± 2.465 to 635.52 ± 11.05 µg/mL. These results indicate that compounds 1, 6 and 9 are potent anti-inflammatory drug candidates while 1 and 3 could be potent antioxidant drugs.  相似文献   

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