首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 16 毫秒
1.
Carboxylic acid derivatives of pyridoxal were developed as potent P2X1 and P2X3 receptor antagonists with modifications of a lead compound, pyridoxal-5′-phosphate-6-azophenyl-2′,5′-disulfonate (5b, iso-PPADS). The designing strategies included the modifications of aldehyde, phosphate or sulfonate groups of 5b, which may be interacted with lysine residues of the receptor binding pocket, to weak anionic carboxylic acid groups. The corresponding carboxylic acid analogs of pyridoxal-5′-phosphate (1), 13 and 14, showed parallel antagonistic potencies. Also, most of 6-azophenyl derivatives (24–28) of compound 13 or 14 showed potent antagonistic activities similar to that of 5b at human P2X3 receptors with 100 nM range of IC50 values in two-electrode voltage clamp (TEVC) assay system on the Xenopus oocyte. The results indicated that aldehyde and phosphoric or sulfonic acids in 5b could be changed to a carboxylic acid without affecting antagonistic potency at mouse P2X1 and human P2X3 receptors.  相似文献   

2.
《Developmental biology》1987,119(1):210-216
Recently, it has been demonstrated that mouse sperm contain a protein with properties similar to the inhibitory guanine nucleotide-binding regulatory protein, Gi (Kopf, G. S., Woolkalis, M. J., and Gerton, G. L. 1986. J. Biol. Chem., 261, 7327–7331). Since sperm-zona pellucida interaction represents a specialized form of intercellular communication and signal transduction we examined the role of the mouse sperm Gi-like protein in the zona pellucida-induced acrosome reaction using mechanically isolated, structurally intact zonae pellucidae. Sperm capacitated for 90 min in the presence of increasing concentrations of islet-activating protein (IAP) bind to the zona pellucida to a similar extent as control sperm incubated in the absence of this toxin. The zona pellucida-induced acrosome reaction, however, is inhibited in a concentration dependent manner by IAP, with half-maximal effects at 0.1-1.0 ng/ml IAP. IAP does not affect the ability of the sperm to become capacitated, but inhibits the cells from progressing into an intermediate stage prior to the completion of the acrosome reaction. When sperm are capacitated in the presence of 100 μM guanosine-5′-O-(3-thiotriphosphate) for 60 min prior to the addition of IAP during the final 30 min, the IAP-induced inhibition of the zona pellucida-induced acrosome reaction is abolished; capacitation in the presence of 100 μM guanosine-5′-O-(2-thiodiphosphate) does not abolish the inhibitory effects of IAP. The target of the IAP effect on intact sperm appears to be at the level of the Gi-like protein since IAP-catalyzed 32P-ADP-ribosylation of the Mr = 41,000 substrate in detergent extracts of sperm is reduced when intact sperm are preincubated with IAP during capacitation. These data suggest that the mouse sperm Gi-like protein plays an intermediary role in the zona pellucida-induced acrosome reaction.  相似文献   

3.
A new meroterpenoid, austalide H acid ethyl ester (1), 5-(2′,4′-dihydroxy-6′-methylphenyl)-3-methylfuran-2-carboxylic acid (2), 5-(2′-hydroxy-6′-methylphenyl)-3-methylfuran-2-carboxylic acid (3) and 5-((6′-methyl-4′-oxo-3′,4′-dihydro-2H-pyran-2′-yl)methyl)-3-methylfuran-2-carboxylic acid (4), along with six known compounds, austalides H, J, K, and P (58), questin (9) and sulochrin (10) were isolated from the lipophilic extract of the alga-derived fungi Penicillium thomii KMM 4645 and Penicillium lividum KMM 4663. The structures of the isolated compounds were determined based on spectroscopic methods. The austalides showed significant inhibitory activity against endo-1,3-β-d-Glucanase from a crystalline stalk of the marine mollusk Pseudocardium sachalinensis.  相似文献   

4.
A library of cathepsin S inhibitors of the dipeptide nitrile chemotype, bearing a bioisosteric sulfonamide moiety, was synthesized. Kinetic investigations were performed at four human cysteine proteases, i.e. cathepsins S, B, K and L. Compound 12 with a terminal 3-biphenyl sulfonamide substituent was the most potent (Ki = 4.02 nM; selectivity ratio cathepsin S/K = 5.8; S/L = 67) and 24 with a 4′-fluoro-4-biphenyl sulfonamide substituent the most selective cathepsin S inhibitor (Ki = 35.5 nM; selectivity ratio cathepsin S/K = 57; S/L = 31). In silico design and biochemical evaluation emphasized the impact of the sulfonamide linkage on selectivity and a possible switch of P2 and P3 substituents with respect to the occupation of the corresponding binding sites of cathepsin S.  相似文献   

5.
Novel pro-apoptotic, homodimeric and heterodimeric Smac mimetics/IAPs inhibitors connected through head–head (8), tail–tail (9) or head–tail linkers (10), were biologically and structurally characterized. In vitro characterization (binding to BIR3 and linker-BIR2–BIR3 domains from XIAP and cIAP1, cytotoxicity assays) identified early leads from each dimer family. Computational models and structural studies (crystallography, NMR, gel filtration) partially rationalized the observed properties for each dimer class. Tail–tail dimer 9a was shown to be active in a breast and in an ovary tumor model, highlighting the potential of dimeric Smac mimetics/IAP inhibitors based on the N-AVPI-like 4-substituted 1-aza-2-oxobicyclo[5.3.0]decane scaffold as potential antineoplastic agents.  相似文献   

6.
《Carbohydrate research》1987,162(2):209-215
The reaction of 2,3,4,3′,4′-penta-O-acetylsucrose (1) with 3.3 mol. equiv. of tert-butyldiphenylsilyl chloride in pyridine in the presence of 4-dimethylamino-pyridine gave the 6,1′,6′-tris(tert-butyldiphenylsilyl) derivative 2 (27%) and the 6,6′-bis(tert-butyldiphenylsilyl) derivative (67%). Oxidation of the HO-1′ in 3 with methyl sulphoxide and trifluoroacetic anhydride gave the 1′-aldehydo derivative 5, which reacted with the stabilised Wittig reagent (Ph3PCHCO2Et) to give the 1′-ethoxycarbonylmethylene derivative 6. Deacetylation of the hepta-acetate 7 of 6 with methanolic sodium methoxide was accompanied by a Michael addition reaction to give 2,1′-anhydro-1′-methoxycarbonylmethylsucrose.  相似文献   

7.
Two 2-amino-1,3,4-thiadiazoles containing phenolic hydroxyl groups were combined with different carboxylic acid chlorides giving sixteen amide derivatives with good antioxidant and antiproliferative potential. The compound 3′c with an adamantane ring displayed excellent DPPH radical scavenging activity and good cytotoxic activity against human acute promyelocytic leukemia HL-60 cells, while 1,3,4-thiadiazole 3′h with 4-chlorophenyl moiety was found to be the most effective in inhibition of survival of lung carcinoma A549 cells. All examined thiadiazoles except 3a and 3′a exerted higher cytotoxic activities on A549 and HL-60 cancer cells when compared with normal fibroblasts MRC-5, pointing to selectivity in their antiproliferative action. Some of the most active novel compounds 3c, 3′c, 3′g and 3′h induced significant increase in the percentage of HL-60 cells in the subG1 cell cycle phase in comparison with the control cells. The induction of cell death in HL-60 cells by these compounds was at least partially dependent on activation of caspase-3 and caspase-8. The compounds 3c and 3′c exerted strong antiangiogenic activity. Furthermore, compounds 3c, 3′c, 3′g and 3′h showed the ability to down-regulate the MMP2 and VEGFA expression levels in the treated HL-60 cells when compared with the control cell samples.  相似文献   

8.
A new coumarin, (?)-cis-(3′R,4′R)-4′-O-angeloylkhellactone-3′-O-β-d-glucopyranoside (1) and two new chalcones, 3′-[(2E)-5-carboxy-3-methyl-2-pentenyl]-4,2′,4′-trihydroxychalcone (4) and (±)-4,2′,4′-trihydroxy-3′-{2-hydroxy-2-[tetrahydro-2-methyl-5-(1-methylethenyl)-2-furanyl]ethyl}chalcone (5) were isolated from the aerial parts of Angelica keiskei (Umbelliferae), together with six known compounds: (R)-O-isobutyroyllomatin (2), 3′-O-methylvaginol (3), (?)-jejuchalcone F (6), isoliquiritigenin (7), davidigenin (8), and (±)-liquiritigenin (9). The structures of the new compounds were determined by interpretation of their spectroscopic data including 1D and 2D NMR data. All known compounds (2, 3, and 69) were isolated as constituents of A. keiskei for the first time. To identify novel hepatocyte proliferation inducer for liver regeneration, 19 were evaluated for their cell proliferative effects using a Hep3B human hepatoma cell line. All isolates exhibited cell proliferative effects compared to untreated control (DMSO). Cytoprotective effects against oxidative stress induced by glucose oxidase were also examined on Hep3B cells and mouse fibroblast NIH3T3 cells and all compounds showed significant dose-dependent protection against oxidative stress.  相似文献   

9.
A synthetic route to (1S,2S,3R,5S)-3-(6-amino-9H-purin-9-yl)-5-fluorocyclopentane-1,2-diol (that is, the 4′-fluoro derivative of 4′-deoxy-5′-noraristeromycin, 3) is described via a fluorinated cyclopentanol, which is in contrast to existing schemes where fluorination occurred once the purine ring was present. Compound 3 was assayed versus a number of viruses. A favorable response was observed towards measles (IC50 of 1.2 μg/mL in the neutral red assay and 14 μg/mL by the visual assay) but this was accompanied by cytotoxicity in the CV-1 host cells (21–36 μg/mL). Among the viruses unaffected by 3 were human cytomegalovirus and the poxviruses (vaccinia and cowpox), which are three viruses that were inhibited by the 4′,4′-difluoro analog of 3 (that is, 2).  相似文献   

10.
Two series of novel 4-chlorophenyl N-alkyl phosphoramidates of 3′-O-(t-butoxycarbonyl)-5-fluoro-2′-deoxyuridine (3′-BOC-FdU) (9a9j) and 5-fluoro-2′-deoxyuridine (FdU) (10a10j) were synthesized by means of phosphorylation of 3′-BOC-FdU (4) with 4-chlorophenyl phosphoroditriazolide (7), followed by a reaction with the appropriate amine. Phosphoramidates 9a9j were converted to the corresponding 10a10j by removal of the 3′-t-butoxycarbonyl protecting group (BOC) under acidic conditions. The synthesized phosphoramidates 9a9j and 10a10j were evaluated for their cytotoxic activity in five human cancer cell lines: cervical (HeLa), nasopharyngeal (KB), breast (MCF-7), liver (HepG2), osteosarcoma (143B) and normal human dermal fibroblast cell line (HDF) using the sulforhodamine B (SRB) assay. Two phosphoramidates 9b and 9j with the N-ethyl and N-(methoxy-(S)-alaninyl) substituents, respectively, displayed remarkable activity in all the investigated cancer cells, and the activity was considerably higher than that of the parent nucleoside 4 and FdU. Among phosphoramidates 10a10j compound 10c with the N-(2,2,2-trifluoroethyl) substituent showed the highest activity. Phosphoramidate 10c was more active than the FdU in all the cancer cell lines tested.  相似文献   

11.
We designed and synthesized human telomere alkylating N-methylpyrrole-N-methylimidazole (PI) polyamide conjugates (16). The C-type conjugates 13 possessed a chlorambucil moiety at the C terminus, whereas the N-type conjugates 46 had one of these moieties at the N terminus. The DNA alkylating activity of these conjugates was evaluated by high-resolution denaturing polyacrylamide gel electrophoresis using a 220 bp DNA fragment containing the human telomere repeat sequence 5′-(GGGTTA)4-3′/5′-(TAACCC)4-3′. C-type conjugates are designed to alkylate the G-rich-strand-containing 5′-GGGTTA-3′ and N-type conjugates were designed to alkylate the complementary C-rich strand-containing 5′-TAACCC-3′ sequence. The difference between conjugates 13 and 46 lies in the linker region between the polyamide moiety and chlorambucil. Conjugates 1 and 4 efficiently alkylated the 5′-GGTTAGGGTTA-3′ and 5′-CCCTAACCCTAA-3′ sequences, respectively, by recognizing 11 bp in the presence of distamycin A (Dist), in a heterotrimeric manner: one long alkylating polyamide conjugate (16) and two short partners (Dist).  相似文献   

12.
As a result of biotransformation of flavanone (1) by the strain Aspergillus niger MB (being the UV mutant) and by the wild strain Penicillium chermesinum 113 the products of hydroxylation at C-6 (2) and C-4′ (5) were obtained. Additionally, three dihydrochalcones with hydroxyl groups at C-2′ (4), C-2′ and C-5′ (3) and C-2′ and C-4 (6) were formed.  相似文献   

13.
The biotransformation of xanthohumol (1), a prenylated chalcone isolated from hops by selected fungi, was investigated. Microbial regioselective glycosylation at the C-4′ position led to xanthohumol 4′-O-β-d-glucopyranoside (2) and xanthohumol 4′-O-β-d-(4′′′-O-methyl)-glucopyranoside (3). The subsequent cyclization of 2 resulted in isoxanthohumol 7-O-β-glucopyranoside (4). The structures of the products were identified based on spectroscopic methods. The biological activity of isolated metabolites has been evaluated. Compared to xanthohumol (1), metabolite 2 is a better 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical scavenger, while 2 and 3 have stronger antiproliferative activity against the human HT-29 colon cancer cell line.  相似文献   

14.
A detailed 1H 220-MHz n.m.r. study of 9-(β-d-xylofuranosyl)adenine 3′,5′-cyclic monophosphate (3′,5′-xylo-cAMP, 1) and 9-(?-d-arabinofuranosyl)adenine 2′,5′-cyclic monophosphate (2′,5′-ara-cAMP, 2) in D2O solution is described. The sugar-ring conformations in 1 and 2 are shown to be 3E and 2E, respectively, and the phosphate rings are in a chair form. An unusual 4JP,H coupling of 2.4 Hz is observed between H-4′ and phosphorus in 1 and a vicinal JP,H of 30.8 Hz between H-5′ and phosphorus in 2. This latter coupling verifies a similar value found previously in the ara-cytidine analog of 2. A comparison of the conformational properties of cyclic nucleotides having fused phosphate and sugar rings has been made, together with an assessment of the use of the Karplus constants in such ring-systems.  相似文献   

15.
The resurgence of mycobacterial infections and the emergence of drug-resistant strains urgently require a new class of agents that are distinct than current therapies. A group of 5-ethynyl (610), 5-(2-propynyloxy) (16, 18, 20, 22, 24), 5-(2-propynyloxy)-3-N-(2-propynyl) (17, 19, 21, 23, 25) and 5-hydroxymethyl-3-N-(2-propynyl) (3033) derivatives of pyrimidine nucleosides were synthesized and evaluated against mycobacteria [Mycobacterium tuberculosis (Mtb), Mycobacterium bovis (BCG) and Mycobacterium avium], gram-positive bacteria (Staphylococcus aureus and Enterococcus faecalis) and gram-negative bacteria (Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa) alone and in combination with existing drugs in in vitro assays. Although several compounds exhibited marked inhibitory activity at a higher concentration against Mtb, M. bovis, S. aureus and E. faecalis, they displayed unexpected synergistic and additive interactions at their lower concentrations with antitubercular drugs isoniazid and rifampicin, and antibacterial drug gentamicin. The active analogues were also found to inhibit intracellular Mtb in a human monocytic cell line infected with H37Ra. Oral administration of 5-hydroxymethyl-3-N-(2-propynyl)-3′-azido-2′,3′-dideoxyuridine (32) and 5-hydroxymethyl-3-N-(2-propynyl)-2′,3′-dideoxyuridine (33) at a dose of 100 mg/kg for two weeks showed promising in vivo effects in mice infected with Mtb (H37Ra). No in vitro cytotoxicity of the test compounds was observed up to the highest concentration tested (CC50 > 300 μg/mL).  相似文献   

16.
We recently reported the discovery of octahydropyrrolo[1,2-a]pyrazine A as a lead compound for an inhibitor of apoptosis proteins (IAP) antagonist. To develop IAP antagonists with favorable PK profiles, we designed novel tri-cyclic compounds, octahydro-1H-cyclopropa[4,5]pyrrolo[1,2-a]pyrazines 1 and 2 based on co-crystal structural analysis of A with cellular IAP-1 (cIAP-1). The additional cyclopropane moiety was used to block the predicted metabolic site of compound A without detriment to the binding affinity for cIAP. Compounds 1 and 2 were stereoselectively synthesized via intermediates 4a and 5b′, which were obtained by Simmons?Smith cyclopropanation of ethylester 3a and silyl ether 3b′. Compounds 1 and 2 showed strong growth inhibition in MDA-MB-231 breast cancer cells and improved metabolic stability in comparison to A. Compound 2 exhibited significant in vivo PD effects to increase tumor necrosis factor-alpha mRNA in a dose dependent manner.  相似文献   

17.
Addition of 5-bromo-2′,3′-O-isopropylidene-5′-O-trityluridine (2) in pyridine to an excess of 2-lithio-1,3-dithiane (3) in oxolane at 78° gave (6R)-5,6-dihydro-(1,3-dithian-2-yl)-2′,3′-O-isopropylidene -5′-O-trityluridine (4), (5S,6S)-5-bromo-5,6-dihydro-(1,3-dithian-2-yl)-2′,3′-O-isopropylidene-5′-O-trityluridine (5), and its (5R) isomer 6 in yields of 37, 35, and 10%, respectively. The structure of 4 was proved by Raney nickel desulphurization to (6S)-5,6-dihydro-2′,3′-O-isopropylidene-6-methyl-5′-O-trityluridine (7) and by acid hydrolysis to give D-ribose and (6R)-5,6-dihydro-6-(1,3-dithian-2-yl)uracil (9). Treatment of 4 with methyl iodide in aqueous acetone gave a 30&%; yield of (R,S)-5,6-dihydro-6-formyl-2′,3′-O-isopropylidene-5′-O-trityl-uridine (10), characterized as its semicarbazone 11. Both 5 and 6 gave 4 upon brief treatment with Raney nickel. Both 5 and 6 also gave 6-formyl-2′,3′-O-isopropylidene-5′- O-trityluridine (12) in ~41%; yield when treated with methyl iodide in aqueous acetone containin- 10%; dimethyl sulfoxide. A by-product, identified as the N-methyl derivative (13) of 12 was also formed in yields which varied with the amount of dimethyl sulfoxide used. Reduction of 12 with sodium borohydride, followed by deprotection, afforded 6-(hydroxymethyl)uridine (17), characterized by hydrolysis to the known 6-(hydroxymethyl)uracil (18). Knoevenagel condensation of a mixture of the aldehydes 12 and 13 with ethyl cyanoacetate yielded 38%; of E- (or Z-)6-[(2-cyano-2-ethoxycarbonyl)ethylidene]-2′,3′-O-isopropylidene-5′-O-trityluridine (19) and 10%; of its N-methyl derivative 20. Hydrogenation of 19 over platinum oxide in acetic anhydride followed by deprotection gave R (or S)-6-(3-amino-2-carboxypropyl)uridine (23).  相似文献   

18.
A sensitive and selective assay for the determination of N-{1(R)-[(1,2-dihydro-1-methylsulfonylspiro[3H-indole-3,4′-piperidin]-1′-yl)carbonyl]-2-(phenylmethoxy)-ethyl}-2-hydroxyamino-2-methylpropanamide (I), a hydroxyl amine metabolite of a novel growth hormone secretagouge (II) has been developed utilizing high-performance liquid chromatography with ion spray tandem mass spectrometric detection (HPLC–MS–MS). The analyte and an internal standard (III) were isolated from the basified biological matrix using a liquid–liquid extraction with methyl tert.-butyl ether (MTBE). The organic extract was evaporated to dryness at room temperature. The residue was reconstituted in the mobile phase and injected into the HPLC–MS–MS system. Multiple reaction monitoring using the precursor→product ion combinations of m/z 545→267 and 543 →267 was used to quantify I and III, respectively, after chromatographic separation under isocratic conditions. The assay was validated in the concentration range of 0.5 to 500 ng/0.1 ml in both human and dog plasma. The precision of the assay, expressed as relative standard deviation, was less than 10% over the entire concentration range with the exception of the low concentration of 0.5 ng/0.1 ml which was 14.0% for human plasma. The HPLC–MS–MS method provided sufficient sensitivity to completely map the pharmacokinetic time course of I following a single 5 mg dose of II to human subjects and a 0.5 mg/kg dose to beagle dogs.  相似文献   

19.
Di(nucleosid-5′-yl) polyphosphates (NPnN) are involved in various biological processes, and constitute signaling molecules in the intermolecular purinergic systems. They exert tumor suppression function and are substrates for specific hydrolases (e.g., HIT proteins). Their structural analogs may serve as molecular probes and potential therapeutic agents. Three P1,P3-bis-thio-analogs of symmetrical di(nucleosid-5′-yl) triphosphates (NP3N) bearing adenosine, guanosine or ribavirin residues (6, 7 and 8, respectively), were obtained by direct condensation of corresponding base-protected nucleoside-5′-O-(2-thio-1,3,2-oxathiaphospholane) with anhydrous phosphoric acid in the presence of DBU. Deprotected products 6 and 8 were separated into individual P-diastereoisomers, whereas 7 was partially separated to yield diastereomerically enriched fractions. The absolute configuration at P-stereogenic centers in the separated diastereoisomers was assigned by RP-HPLC analysis of the products of enzymatic digestion with snake venom phosphodiesterase. The Fhit-assisted hydrolysis rates for 6 and 7 are by 2–3 orders of magnitude lower than that for the reference AP3A, and depend on the configuration of the stereogenic phosphorus atoms, while 8 occurred to be resistant to this cleavage.  相似文献   

20.
Phytochemical investigation of the rhizomes of Smilax trinervula led to isolation and structure elucidation of eight lignan glycosides, including five new lignans, namely, (7S, 8R, 8′R)-4, 4′, 9-trihydroxy-3, 3′, 5, 5′-tetramethoxy-7, 9′-epoxylignan-7′-one 4′-O-β-d-glucopyranoside (1), (7S, 8R, 8′R)-4, 4′, 9-trihydroxy-3, 3′, 5, 5′-tetramethoxy-7, 9′-epoxylignan-7′-one 4-O-β-d- glucopyranoside (2) (7S, 8R)-4, 9, 9′-trihydroxy-3, 3′, 5-trimethoxy-4′, 7-epoxy-8, 5′-neolignan 9′-O-β-d-glucopyranoside (3), (7R, 8R)-4, 9, 9′-trihydroxy-3, 5-dimethoxy-7.O.4′, 8.O.3′- neolignan 9′-O-β-d-glucopyranoside (4), and (7S, 8R)-4, 9, 9′-trihydroxy-3, 3′, 5-trimethoxy-8, 4′-oxy-neolignan 4-O-β-d-glucopyranoside (5), along with three known compounds (6-8). Their structures were established mainly on the basis of 1D and 2D NMR spectral data, ESI–MS and comparison with the literature. Compounds 1-8 were tested in vitro for their cytotoxic activity against four human tumor cell lines (SH-SY5Y, SGC-7901, HCT-116, Lovo). Compounds 3 and 5 exhibited cytotoxic activity against Lovo cells, with IC50 value of 10.4 μM and 8.5 μM, respectively.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号