Synthesis,crystallographic and spectroscopic characterization and magnetic properties of dimer and monomer ternary copper(II) complexes with sulfonamide derivatives and 1,10-phenanthroline. Nuclease activity by the oxidative mechanism

Three dinuclear and one mononuclear copper(II)-1,10-phenanthroline ternary complexes, [Cu(L1)(phen)(OH)]₂ (1), [Cu(L2)(phen)(OH)]₂·3H₂O (2), [Cu(L3)(phen)(OH)]₂ (3) and [Cu(L4)₂(phen)(H₂O)] (4), with thiadiazole sulfonamide derivative ligands: HL1 (N-(5-ethyl-1,3,4-thiadiazol-2-yl)naphthalene-1-sulfonamide), HL2 (N-(5-ethylthio)-1,3,4-thiadiazol-2-yl)-4-methylbenzenesulfonamide), HL3 (N-(5-ethyl-1,3,4-thiadiazol-2-yl)benzenesulfonamide) and HL4 (N-(5-ethyl-1,3,4-thiadiazol-2-yl)-4-methylbenzenesulfonamide) have been synthesized and characterized. In the four complexes each copper atom is five-coordinated. The structure of complexes 1, 2 and 3 consists of a dimeric unit with a C2 symmetry axis, where both coppers are bridged by two hydroxo anions. Magnetic measurements show that the dimer complexes are ferromagnetic according to the Cu–O–Cu angles. Cleavage experiments using pUC18 plasmid DNA in the presence of H₂O₂/ascorbic acid as an activating agent show that the title complexes are potent artificial chemical nucleases, the order of efficiency being 3 > 2 ∼ 1 > 4. Control cleavage experiments indicated that the dimer complexes are stronger artificial nucleases than the [Cu(phen)₂]²⁺ complex under the same experimental conditions, while the monomer 4 has a lower nuclease activity than the [Cu(phen)₂]²⁺ complex. The inhibition of the cleavage process in the presence of reactive oxygen intermediate scavengers suggests that the hydroxyl radical and the superoxide anion are reactive species for the breakage of the DNA strands.     

超高效液相色谱-串联质谱法检测鸡粪中16种残留抗生素

建立了固相萃取-超高效液相色谱-串联质谱(UPLC-MS/MS)同时检测畜禽粪便中四环素类、磺胺类、氟喹诺酮类和大环内酯类16种抗生素的分析方法.针对目标物化学性质和样品杂质情况,对质谱条件、提取液种类、超声功率等参数进行了优化.最终以50%乙腈(V/V)的磷酸盐缓冲溶液(pH=4)提取3次,经过超声、离心、旋蒸、稀释后,SAX-HLB串联小柱净化富集,用10 mL甲醇-丙酮混合液(80∶20,V/V)洗脱,35℃氮吹近干后,用含0.1%甲酸-甲醇(1∶1, V/V)定容,在UPLC-MS/MS多反应检测模式下进行定性及定量分析.结果表明,粪便中四环素类、磺胺类、氟喹诺酮类和大环内酯类抗生素的平均加标回收率为56.4%~94.6%,相对标准偏差(RSD)在2.6%~19.8%之间,方法检出限(LOD, S/N=3)和定量限(LOQ, S/N=10)分别为0.01~2.50 μg/ kg和0.05~7.90 μg/kg.本方法简便、稳定性好、灵敏度高、重现性好,适用于畜禽粪便中多种抗生素的同时检测.     

新型青蒿砜-哌嗪-磺酰胺类衍生物的合成及抗癌活性

以双氢青蒿素为起始原料,经胺化、氧化、烷基化、胺化和酰化反应,快速、高效地合成了青蒿砜及其衍生物,并对所有化合物进行了结构确定.采用四甲基偶氮唑盐比色法(MTT法)研究了该类化合物对人肝癌细胞株SMMC-7721的细胞毒活性,初步研究结果表明,该类化合物具有明显的抑制人肝癌细胞增殖、诱导其凋亡的细胞活性,给药72h,半抑制浓度IC50最优值为0.09μmol/mL.     

Synthesis of cinchonidinium salts containing sulfonamide functionalities and their catalytic activity in asymmetric alkylation reactions

Various kinds of 4-(bromomethyl)benzenesulfonamides were prepared as quaternization reagent of cinchonidine. Cinchonidinium salts obtained from the quaternization of cinchonidine with 4-(bromomethyl)benzenesulfonamide showed highly enantioselective catalytic activity in the asymmetric benzylation of N-(diphenylmethylene)glycine tert-butyl ester. The corresponding phenylalanine derivative was obtained in high yield with a high level of enantioselectivity, up to 98% ee.     

A novel method for preparation of 8-hydroxyquinoline functionalized mesoporous silica: Aluminum complexes and photoluminescence studies

8-Hydroxyquinoline (8-HQ) was attached to mesoporous silica by sulfonamide bond formation between 8-hydroxyquinoline-5-sulfonyl chloride (8-HQ-SO₂Cl) and aminopropyl functionalized SBA-15 (designated as SBA-SPS-Q) and then aluminum complexes of 8-HQ was covalently bonded to SBA-SPS-Q using coordinating ability of grafted 8-HQ.The prepared materials were characterized by powder X-ray diffraction (XRD), nitrogen adsorption-desorption, Fourier transform infrared (FT-IR), thermal analysis (TGA-DTA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), elemental analysis and fluorescence spectra. The environmental effects on the emission spectra of grafted 8-HQ and its complexes were studied and discussed in details.     

Multi-biofunctional complexes combining antiseptic copper(II) with antibiotic sulfonamide ligands: Structural, redox and antibacterial study

Copper(II) and nickel(II) complexes of sulfadimethoxine, sulfadiazine, sulfamerazine and sulfamethazine were synthesized with a good yield according to an original procedure. These complexes were first characterized by single-crystal X-ray diffraction and electrochemistry. Structural inspections showed that the antibacterial entity of ligands remains non-coordinated to metal ions in the complex high-lighting the fact that in each cluster, antiseptic activity of the metal has been associated to the antibiotic activity of the ligand. In order to confirm this possibility, antibacterial activities of the complexes were studied on several bacteria. The antibacterial activity of the complex is as important as the ligands one with the addition of antiseptic activity via the incorporation of copper ions.     

Determination of sulfonamide antibiotics in fish and shrimp samples based on magnetic carbon nanotube dummy molecularly imprinted polymer extraction followed by UPLC-MS/MS

In this study, a novel purification method using magnetic solid-phase extraction (MSPE) based on magnetic carbon nanotube dummy molecularly imprinted polymer (MCNTMIP) nanocomposite was investigated for separation and enrichment of sulfonamide antibiotics (SAs) in fish and shrimp samples. The MCNTMIP nanocomposite was successfully synthesized by applying carbon nanotubes as supporting template, methacrylic acid as functional monomer, sulfabenzamide as the dummy template for SAs, and ethylene glycol dimethacrylate as crosslinking agent, then was characterized by Fourier-transform infrared spectrometry and vibrating sample magnetometry. The adsorption performance of MCNTMIP was evaluated by binding experiments, including static adsorption, kinetic adsorption, and selectivity recognition study. The results confirmed that an imprinted polymer layer was successfully constructed on the surface of the MCNTMIP and this sorbent has advantages of simple magnetic separation, specific molecular recognition, and high adsorption capacity. Combined with ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS), we developed a rapid, sensitive, efficient MSPE method for detecting SAs analytes. Under the optimal conditions, the limits of detection were low to 0.1 μg/kg, and the recoveries of SAs analytes were ranged between 90.2 and 99.9%. In addition, the precision values were ranged between 0.5 and 9.1%. This method was successfully applied to analyze SAs in fish and shrimp samples with satisfactory recoveries.     

Affinity biosensors based on disposable screen-printed electrodes modified with DNA

Simple and sensitive DNA sensors have been developed on a base on graphite screen-printed electrodes modified with DNA and enzymes. Cholinesterase and peroxidase immobilized by treatment with glutaraldehyde were used for the detection of human DNA antibodies of systemic lupus erythematosus and bronchial asthma patients. The amperometric signal was measured at +680 mV versus Ag/AgCl for DNA-cholinesterase sensor and −150 mV for DNA-peroxidase sensor 5 min after the injection of acethylthiocholine and hydroquinone, respectively. The addition of serum samples results in the sharp decrease of the signal due to the formation of DNA-antibody adducts followed by the suppression of the access of substrate to the enzyme active site. Sulfonamide medicines suppress the DNA-antibody interaction due to the competitive binding along DNA minor grooves. DNA sensor labeled with peroxidase showed the linear calibration range of 5×10⁻⁹ to 7×10⁻⁵ mol l⁻¹ of sulfamethoxazole and of 5×10⁻⁸ to 1×10⁻⁴ mol l⁻¹ of sulfathiazole.     

Synthesis and pharmacological effects of novel benzenesulfonamides carrying benzamide moiety as carbonic anhydrase and acetylcholinesterase inhibitors

N -(1-(4-Methoxyphenyl)-3-oxo-3-((4-( N -(substituted)sulfamoyl)phenyl)amino)prop-1-en-1-yl)benzamides 3a – g were designed since sulfonamide and benzamide pharmacophores draw great attention in novel drug design due to their wide range of bioactivities including acetylcholinesterase (AChE) and human carbonic anhydrase I and II (hCA I and hCA II) inhibitory potencies. Structure elucidation of the compounds was carried out by 1H NMR, 13C NMR, and HRMS spectra. In vitro enzyme assays showed that the compounds had significant inhibitory potential against hCA I, hCA II, and AChE enzymes at nanomolar levels. Ki values were in the range of 4.07 ± 0.38 – 29.70 ± 3.18 nM for hCA I and 10.68 ± 0.98 – 37.16 ± 7.55 nM for hCA II while Ki values for AChE were in the range of 8.91 ± 1.65 – 34.02 ± 5.90 nM. The most potent inhibitors 3g (Ki = 4.07 ± 0.38 nM, hCA I), 3c (Ki = 10.68 ± 0.98 nM, hCA II ) , and 3f (Ki = 8.91 ± 1.65 nM, AChE) can be considered as lead compounds of this study with their promising bioactivity results. Secondary sulfonamides showed promising enzyme inhibitory effects on AChE while primary sulfonamide derivative was generally effective on hCA I and hCA II isoenzymes.