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排序方式: 共有350条查询结果,搜索用时 609 毫秒
31.
Raju Dash Mir Muhammad Nasir Uddin S.M. Zahid Hosen Zahed Bin Rahim Abu Mansur Dinar Mohammad Shah Hafez Kabir Ramiz Ahmed Sultan Ashekul Islam Md Kamrul Hossain 《Bioinformation》2015,11(12):543-549
Cyclooxygenase-2 (COX-2) catalyzed synthesis of prostaglandin E2 and it associates with tumor growth, infiltration, and metastasis
in preclinical experiments. Known inhibitors against COX-2 exhibit toxicity. Therefore, it is of interest to screen natural compounds
like flavanoids against COX-2. Molecular docking using 12 known flavanoids against COX-2 by FlexX and of ArgusLab were
performed. All compounds showed a favourable binding energy of >-10 KJ/mol in FlexX and > -8 kcal/mol in ArgusLab.
However, this data requires in vitro and in vivo verification for further consideration. 相似文献
32.
The neurotransmitter dopamine is oxidized to its quinone (DA-Q), which at neutral pH undergoes intramolecular cyclization by 1,4-Michael addition, followed by oxidation to form leukochrome, then aminochrome, and finally neuromelanin. At lower pH, the amino group of DA is partially protonated, allowing the competitive intermolecular 1,4-Michael addition with nucleophiles in DNA to form the depurinating adducts, DA-6-N3Ade and DA-6-N7Gua. Catechol estrogen-3,4-quinones react by 1,4-Michael addition to form the depurinating 4-hydroxyestrone(estradiol)-1-N3Ade [4-OHE1(E2)-1-N3Ade] and 4-OHE1(E2)-1-N7Gua adducts, which are implicated in the initiation of breast and other human cancers. The effect of pH was studied by reacting tyrosinase-activated DA with DNA and measuring the formation of depurinating adducts. The most adducts were formed at pH 4, 5, and 6, and their level was nominal at pH 7 and 8. The N3Ade adduct depurinated instantaneously, but N7Gua had a half-life of 3 H. The slow loss of the N7Gua adduct is analogous to that observed in previous studies of natural and synthetic estrogens. The antioxidants N-acetylcysteine and resveratrol efficiently blocked formation of the DA-DNA adducts. Thus, slightly acidic conditions render competitive the reaction of DA-Q with DNA to form depurinating adducts. We hypothesize that formation of these adducts could lead to mutations that initiate Parkinson's disease. If so, use of N-acetylcysteine and resveratrol as dietary supplements may prevent initiation of this disease. 相似文献
33.
Lupberger J Zeisel MB Xiao F Thumann C Fofana I Zona L Davis C Mee CJ Turek M Gorke S Royer C Fischer B Zahid MN Lavillette D Fresquet J Cosset FL Rothenberg SM Pietschmann T Patel AH Pessaux P Doffoël M Raffelsberger W Poch O McKeating JA Brino L Baumert TF 《Nature medicine》2011,17(5):589-595
Hepatitis C virus (HCV) is a major cause of liver disease, but therapeutic options are limited and there are no prevention strategies. Viral entry is the first step of infection and requires the cooperative interaction of several host cell factors. Using a functional RNAi kinase screen, we identified epidermal growth factor receptor and ephrin receptor A2 as host cofactors for HCV entry. Blocking receptor kinase activity by approved inhibitors broadly impaired infection by all major HCV genotypes and viral escape variants in cell culture and in a human liver chimeric mouse model in vivo. The identified receptor tyrosine kinases (RTKs) mediate HCV entry by regulating CD81-claudin-1 co-receptor associations and viral glycoprotein-dependent membrane fusion. These results identify RTKs as previously unknown HCV entry cofactors and show that tyrosine kinase inhibitors have substantial antiviral activity. Inhibition of RTK function may constitute a new approach for prevention and treatment of HCV infection. 相似文献
34.
35.
Islam MS Rahman MZ Khan SI Mahmud ZH Ramamurthy T Nair GB Sack RB Sack DA 《Microbiology and immunology》2005,49(8):779-784
The organization of the CTX prophage in environmental strains of Vibrio mimicus was investigated. Sixteen hundred non-sucrose fermenting vibrios were examined for ctx gene by hybridization. Out of 1,600 isolates, 6 V. mimicus isolates contained ctxA gene. The organization of CTX prophage was determined by RFLP using ctxA probe. The CTX prophage integrated at a single site in V. mimicus genome which was present as a single copy flanked by at least a single RS element. Ribotype pattern revealed that a particular clone of V. mimicus acquired the CTXPhi in the aquatic environment. This study demonstrated that V. mimicus could act as a reservoir of CTXPhi in the aquatic environment. 相似文献
36.
Ali MS Khan SR Ojima H Guzman IY Whitmire KH Siddik ZH Khokhar AR 《Journal of inorganic biochemistry》2005,99(3):795-804
A series of platinum(II) and (IV) monoadducts of the type [Pt(II)(DACH)LCl]NO3 and [Pt(IV)(DACH)trans-(X)2LCl]NO3 (where DACH=trans-1R,2R-diaminocyclohexane, L=adenine, guanine, hypoxanthine, cytosine, adenosine, guanosine, inosine, cytidine, 9-ethylguanine (9-EtGua), or 1-methylcytosine and X=hydroxo or acetato ligand) have been synthesized and characterized by elemental analysis and by 1H and 195Pt nuclear magnetic resonance (NMR) spectroscopy. The crystal structure of the model nucleobase complex [Pt(IV)(trans-1R,2R-diaminocyclohexane)trans-(acetate)2(9-EtGua)Cl]NO3.H2O was determined using a single crystal X-ray diffraction method. The compound crystallized in the monoclinic space group P2(1), with a=10.446(2) A, b=22.906(5) A, c=10.978(2) A, Z=4, and R=0.0718, based upon the total of 11,724 collected reflections. In this complex, platinum had a slightly distorted octahedron geometry owing to the presence of a geometrically strained five-member ring. The two adjacent corners of the platinum plane were occupied by the two amino nitrogen of DACH, whereas, the other two equatorial positions occupied by chloride ion and 9-ethylguanine. The remaining two axial positions were occupied by the oxygen atoms of acetato ligands. The DACH ring was in a chair configuration. An intricate network of intermolecular hydrogen bonds held the crystal lattice together. Some of these synthesized models of DACH-Pt-DNA adducts have good in vitro cytotoxic activity against the cisplatin-sensitive human cancer ovarian A2780 cell line (IC50=1-8 microM). Interestingly, a substituted nucleobase (9-ethylguanine) adduct was over 6-fold more potent than regular adducts. The cross-resistance factor against the 44-fold cisplatin-resistant 2780CP/clone 16 cells was about 3-9; thus, the cytotoxicity of adducts was indicative of low potency, but the resistance factors were also substantially low. These results suggest that DNA adducts of DACH-Pt are cytotoxic with low cross-resistance. 相似文献
37.
Chohan ZH Supuran CT Scozzafava A 《Journal of enzyme inhibition and medicinal chemistry》2005,20(3):303-307
Four novel cobalt(II), copper(II), nickel(II) and zinc(II) complexes of the fluoroquinolone antibiotic ciprofloxacin have been prepared. The compounds were characterized by IR, UV-Visible, molar conductivity and elemental analyses. In all of the complexes, the drug ligand, ciprofloxacin (CFL) was coordinated through two carbonyl oxygen atoms. Octahedral and square-planar geometries have been proposed for the cobalt(II), nickel(II) and zinc(II), and copper(II) complexes, respectively. In vitro tests of susceptibility to these metal complexes showed stronger activity than that of ciprofloxacin against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Bacillus dysenteriae. 相似文献
38.
Chohan ZH Pervez H Rauf A Khan KM Supuran CT 《Journal of enzyme inhibition and medicinal chemistry》2006,21(2):193-201
A series of Co (II), Cu (II), Ni (II) and Zn (II) complexes of mercaptothiadiazole-derived furanyl, thienyl, pyrrorlyl, salicylyl and pyridinyl Schiff bases were synthesized, characterized and screened for their in vitro antibacterial activity against four Gram-negative, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi and Shigella fexneri, and two Gram-positive; Bacillus subtilis and Staphylococcus aureous bacterial strains. The results of these studies show the metal complexes to be more antibacterial as compared to the prepared un-complexed Schiff bases. 相似文献
39.
Chohan ZH Arif M Shafiq Z Yaqub M Supuran CT 《Journal of enzyme inhibition and medicinal chemistry》2006,21(1):95-103
Isonicotinoylhydrazide Schiff's bases formed by the reaction of substituted and unsubstituted furyl-2-carboxaldehyde and thiophene-2-carboxaldehyde with isoniazid and, their Co (II), Cu (II), Ni (II) and Zn (II) complexes have been synthesized, characterized and screened for their in vitro antibacterial activity against Mycobacterium tuberculosis, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella typhi, Shigella dysenteriae, Bacillus cereus, Corynebacterium diphtheriae, Staphylococcus aureus and Streptococcus pyogenes bacterial strains and for in vitro antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glabrata. The results of these studies show the metal complexes to be more antibacterial and antifungal against one or more bacterial/fungal strains as compared to the uncomplexed compounds. The brine shrimp bioassay indicated Schiff's bases, L3 and L6 and, their Cu (II) and Ni (II) metal complexes to be cytotoxic against Artemia salina, while all other compounds were inactive (LD50 > 1000). 相似文献
40.
Chohan ZH Rauf A Naseer MM Somra MA Supuran CT 《Journal of enzyme inhibition and medicinal chemistry》2006,21(2):173-177
A series of antibacterial and antifungal sulfonamide (sulfanilamide, sulfaguanidine, sulfamethaxozole, 4-aminoethylbenzene-sulfonamide and 4-amino-6-trifluoromethyl-benzene-1,3-disulfonamide) derived chromones, previously reported as inhibitors of carbonic anhydrase, have been screened for in-vitro antibacterial activity against four Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi and Shigella flexener) and two Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacterial strains, and for in-vitro antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani, Candida glaberata. All compounds (1)-(5) showed significant antibacterial activity against all four Gram-negative species and both Gram-positive species. However, three of them, (1), (4) and (5), were found to be comparatively much more active compared to (2) and (3). Of these, (5) was found to be the most active one. For antifungal activity, generally compounds (1) and (2) showed significant activity against more than three strains whereas (3)-(5) also showed significant activity against varied fungal strains. In the brine shrimp bioassay for in-vitro cytotoxic properties, only two compounds, (4) and (5) displayed potent cytotoxic activity, LD50 = 2.732 x 10(-4)M) and LD50 = 2.290 x 10(-4)M) respectively, against Artemia salina. 相似文献