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1.
Antispasmodic agents are used for modulating gastrointestinal motility. Several compounds isolated from terrestrial plants have antispasmodic properties. This study aimed to explore the inhibitory effect of the pyrrolidine derivative, asperidine B, isolated from the soil-derived fungus Aspergillus sclerotiorum PSU-RSPG178, on spasmodic activity. Isolated rat ileum was set up in an organ bath. The contractile responses of asperidine B (0.3 to 30 µM) on potassium chloride and acetylcholine-induced contractions were recorded. To investigate its antispasmodic mechanism, CaCl2, acetylcholine, Nω-nitro-l-arginine methyl ester (l-NAME), nifedipine, methylene blue and tetraethylammonium chloride (TEA) were tested in the absence or in the presence of asperidine B. Cumulative concentrations of asperidine B reduced the ileal contraction by ~37%. The calcium chloride and acetylcholine-induced ileal contraction was suppressed by asperidine B. The effects of asperidine B combined with nifedipine, atropine or TEA were similar to those treated with nifedipine, atropine or TEA, respectively. In contrast, in the presence of l-NAME and methylene blue, the antispasmodic effect of asperidine B was unaltered. These results suggest that the antispasmodic property of asperidine B is probably due to the blockage of the L-type Ca2+ channel and is associated with K+ channels and muscarinic receptor, possibly by affecting non-selective cation channels and/or releasing intracellular calcium.  相似文献   

2.
Thirteen novel bis-1,2,3-triazole derivatives were synthesized under copper (I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition of N,N′-(hexane-1,6-diyl)bis(4-methyl-N-(prop-2-yn-1-yl)benzenesulfonamide) with different aryl azides and evaluated their biological activity. All the newly synthesized compounds were confirmed by 1H-NMR, infrared, and elemental analysis and mass spectral studies. The synthesized bis-1,2,3-triazoles were evaluated for their antioxidant activity, and some of them were found to exhibit good to excellent antioxidant activity (IC50: 11.13 ± 1.5 to 98.98 ± 1.7 μM) in comparison with standard references, Trolox (11.73 ± 1.5 μM) and ascorbic acid (3.34 ± 1.8 μM). The bistriazoles also exhibited excellent-to-moderate anti-bacterial activity (MIC: 2.253 to 75 µg mL?1 against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa when compared with streptomycin. N,N′-(hexane-1,6-diyl)bis(N-((1-(3,5-dimethylphenyl)-1H-1,2,3-triazol-4-yl)methyl)-4-methyl benzenesulfonamide) has completely cleaved the DNA at a concentration of 100 mg mL?1, and the remaining compounds have partially cleaved the DNA.  相似文献   

3.
A novel series of Zn(II) complexes [LnZnCl2] (Ln = LA ? LF) based on N,N′,N-bis((1H-pyrazol-1-yl)methyl)amine bidentate ligands, N,N-bis((1H-pyrazol-1-yl)methyl)-3,5-dimethylaniline [LA], N,N-bis((1H-pyrazol-1-yl)methyl)-2,6-dimethylaniline [LB], N,N-bis((1H-pyrazol-1-yl)methyl)-2,6-diethylaniline [LC], N,N-bis((1H-pyrazol-1-yl)methyl)-2,6-diisopropylaniline [LD], N,N-bis((1H-pyrazol-1-yl)methyl)-4-bromoaniline [LE] and N,N-bis((1H-pyrazol-1-yl)methyl)benzhydrylamine [LF], has been synthesized and characterized. X-ray structures of these Zn(II) complexes showed a distorted tetrahedral geometry. No interaction exists between the Namine and the Zn(II) center in the [LnZnCl2] (Ln = LA ? LF) complexes, resulting in formation of an eight-membered chelate ring. [LFZnCl2] exhibited the highest catalytic activity (3.95 × 104 g PMMA/mol·Zn·h) for the polymerization of methyl methacrylate (MMA) in the presence of modified methylaluminoxane (MMAO) at 60 °C and yielded high molecular weight (Mw) (11.0 × 105 g/mol) of poly(methylmethacrylate) (PMMA). All the complexes resulted in syndiotactic enriched PMMA with high Tg (125–131 °C). The steric bulk of ligand architecture plays an influential role in controlling the catalytic activity and stereoregularity of the resultant PMMA. Further, alkyl derivatives [LnZnMe2] (Ln = LA ? LF) of synthesized Zn(II) complexes, generated in situ, showed moderate to high activities toward ring opening polymerization (ROP) of rac-lactide (rac-LA) and yielded heterotactic polylactide (PLA) with Pr up to 0.95 at ?50 °C. The activity and stereoselectivity toward ROP of rac-LA by these dimethyl Zn(II) complexes should be considered as a combined effect of steric hindrance and electronic density around the metal center.  相似文献   

4.
5.
The Bigenelli acid catalyzed condensation of 2‐trifluoromethylbenzaldehyde ( 1 ), urea ( 2 ) and an alkyl acetoacetate ( 3 ) afforded the respective alkyl (Me, Et, i‐Pr, i‐Bu) 6‐methyl‐4‐(2‐trifluoromethylphenyl)‐1,2,3,4‐tetrahydro‐2H‐pyrimidine‐2‐one‐5‐carboxylate ( 4‐7 ). Subsequent N3‐nitration of the alkyl esters ( 4‐7 ) using Cu(NO3)2 3H2O and Ac2O furnished the target alkyl 6‐methyl‐3‐nitro‐4‐(2‐trifluoromethylphenyl)‐1,2,3,4‐tetrahydro‐2H‐pyrimidine‐2‐one‐5‐carboxylates ( 8‐11 ). The N3‐nitro compounds ( 8‐11 ) were less potent calcium channel antagonists (IC50 values in the 1.9 × 10?7 to 3.9 × 10?6 M range) on guinea pig ileal longitudinal smooth muscle than the reference drug nifedipine (Adalat®, IC50 = 1.4 × 10?8 M). In vitro calcium channel modulation studies on guinea pig left atrium (GPLA) showed that the methyl and ethyl esters ( 8‐9 ) induced a weak‐to‐modest positive inotropic (agonist) effect, and that the inactive isopropyl ( 10 ) and isobutyl ( 11 ) esters did not alter the cardiac contractile force of GPLA.  相似文献   

6.
Mononuclear cobalt(II), nickel(II), and copper(II) complexes of cetirizine·2HCl (CTZ = 2-[2-[4-[(4-chlorophenyl)phenyl methyl]piperazine-1-yl]-ethoxy]acetic acid) in the presence of alanine (Ala) as a representative example of amino acids were synthesized and elucidated by different physical techniques. All complexes have been characterized with the help of elemental analyses, molecular weights, molar conductance values, magnetic moments, and spectroscopic data. The measured molar conductance values in DMSO indicate that the complexes are nonelectrolytes. Quantum chemical calculations were performed with semi-empirical method to find the optimum geometry of complexes. The metal–oxygen bond length in the synthesized complexes obeys the order M–OH2 > M–OCTZ > M–OAla. Formation equilibria of the ternary complexes have been investigated. Ternary complexes are formed by a simultaneous mechanism. Stoichiometry and stability constants for the complexes formed are reported. The concentration distributions of various species formed in solution were also evaluated as a function of pH. CTZ and its metal chelates have been screened for their antimicrobial activities against some selected types of gram-positive (G+) and gram-negative (G?) bacteria. They were more active against (G+) than (G?) bacteria.  相似文献   

7.
Gao  Fang  Ding  Li  Ma  Pengcheng  Wu  Fei 《Chromatographia》2010,71(11):1007-1014

Zofenoprilat is an active metabolite of zofenopril, which is very unstable in plasma because of oxidative degradation of its thiol group. In this method, p-bromophenacyl bromide was used as derivatization reagent, immediately after plasma separation, to react with the free thiol group of zofenoprilat and form the derivative zofenoprilat-p-BPB. After acidification with 50% acetic acid, the derivatized plasma samples were extracted with methyl tert-butyl ether and separated on a C18 column with 40:60 (v/v) 10 mM ammonium acetate buffer solution containing 0.1% formic acid–acetonitrile as mobile phase. Calibration plots were linear over the concentration range 1–500 ng mL−1 for zofenopril and 2–1,800 ng mL−1 for zofenoprilat. The method was successfully used to study the bioavailability of zofenopril calcium capsules relative to that of zofenopril calcium tablets in healthy Chinese volunteers.

  相似文献   

8.
The new analogues of nifedipine, in which 2-nitrophenyl group at position 4 is replaced by phenylisoxazolyl substituent, were synthesized. The symmetrical dialkyl 1,4-dihydro-2,6-dimethyl-4-(5-phenylisoxazol-3-yl)pyridine-3,5-dicarboxylates were prepared by classical Hantzsch condensation, and the asymmetrical analogues were synthesized using a procedure reported by Dagnino that involved the condensation of alkyl acetoacetate with alkyl 3-aminocrotonate and 5-phenylisoxazole-3-carboxaldehyde. The structure of all compounds was confirmed by IR, 1H NMR and Mass spectra. In vitro calcium channel antagonist activities were evaluated as calcium channel antagonists using the high K+ concentration of guinea-pig ileum longitudinal smooth muscle (GPILSM) assay. These compounds exhibited moderate calcium antagonist activity (IC50 = 10?7 to 10? 5 M range) relative to the reference drug nifedipine (IC50 = 1.10 ± 0.40 × 10?8 M).  相似文献   

9.
Two new Schiff base silver(I) complexes, {[Ag(L1)][H2O]} (1) and {[Ag(L2)][H2O]} (2), where L1 = 4-((2-diethylaminoethylimino)methyl)phenecarboxylate and L2 = 4-([3-(morpholin-4-yl)propyl]iminomethyl)phenecarboxylate, have been synthesized and characterized. X-ray crystallographic analysis reveals that silver ions in 1 are bridged by L1 to form a one-dimensional zigzag chain, while three silver ions in 2 are linked by L2 to produce a two-dimensional coordination polymer. Guest water molecules in 1 generate a one-dimensional hydrogen-bonded chain. Both 1 and 2 offer high antibacterial activity against Gram-positive bacteria Staphylococcus aureus with MIC values of 0.26 and 0.24 mM and to exhibit good inhibitory activity against urease with the respective IC50 values of 3.5 ± 0.1 and 3.8 ± 0.2 μM.  相似文献   

10.
The Bigenelli acid catalyzed condensation of 2‐pyridylcarboxaldehyde ( 1 ), urea ( 2 ) and an alkyl acetoacetate ( 3 ) afforded the respective alkyl (Me, Et, i‐Pr, i‐Bu, t‐Bu) 6‐methyl‐4‐(2‐pyridyl)‐1,2,3,4‐tetrahydro‐2H‐pyrimidine‐2‐one‐5‐carboxylates ( 4a‐e ). The most potent calcium channel antagonist ethyl 6‐methyl‐4‐(2‐pyridyl)‐1,2,3,4‐tetrahydro‐2H‐pyrimidine‐2‐one‐5‐carboxylate ( 4b , IC50 = 1.67 × 10?5 M) wasa much weaker calcium channel antagonist than the reference drug nifedipine (Adalat®, IC50 = 1.40 × 10?8 M) on guinea pig ileal longitudinal smooth muscle (GPILSM). The alkyl 6‐methyl‐4‐(2‐pyridyl)‐1,2,3,4‐tetrahydro‐2H‐pyrimidine‐2‐one‐5‐carboxylates did not show any inotropic effect on heart since no increase, or decrease, in the contractile force of guinea pig left atrium was observed. These structure activity studies show that the alkyl 6‐methyl‐4‐(2‐pyridyl)‐1,2,3,4‐tetrahydro‐2H‐pyrimidine‐2‐one‐5‐carboxylates ( 4a‐e ) are partial bioisosteres of nifedipine with respect to calcium channel antagonist activity on guinea pig ileal longitudinal smooth muscle (GPILSM).  相似文献   

11.
Abstract

4‐(3′,4′‐Dimethoxycinnamoyl)phenyl acrylate (DMCPA) containing pendant chalcone moiety was copolymerized with methyl methacrylate (MMA) by radical polymerization in ethyl methyl ketone at 70°C under a nitrogen atmosphere using benzoyl peroxide (BPO) as a free radical initiator. The prepared polymer was characterized by UV, FT‐IR, 1H‐NMR, and 13C‐NMR spectra. The composition of the copolymer was determined using 1H‐NMR analysis. The monomer reactivity ratios of copolymerization were determined using conventional linearization methods such as Fineman–Ross (r 1 = 0.26 and r 2 = 0.61), Kelen–Tudos (r 1 = 0.26 and r 2 = 0.61), and Ext. Kelen–Tudos (r 1 = 0.23 and r 2 = 0.59), and a non‐linear error‐in‐variables model (EVM) method using the computer program RREVM (r 1 = 0.2541 and r 2 = 0.6094). The molecular weights (M w and M n) of the copolymers were determined by gel permeation chromatography. Thermogravimetric analysis of the polymers in air reveals that the stability of the copolymers decreases with an increase in the mole fraction of MMA in the copolymers. The solubility of the polymers was tested in various polar and non‐polar solvents. The glass transition temperature of the copolymers was determined as a function of copolymer composition. The copolymers were sensitive to UV light and became crosslinked after irradiation with 254 nm light.  相似文献   

12.
Schiff base pyridin-2-ylimino methyl naphthanol (HL) was synthesized and characterized by spectroscopic (FTIR, ESIMS, and NMR) techniques. The ligand was reacted with perchlorate salts of Mn+2, Co+2, and Ni+2. ESIMS mass spectra indicate the formation of mononuclear complex ML2 for all three complexes. CoL2 crystallizes in P21/n space group, adopting a distorted tetrahedral geometry where Co is in a N2O2 donor environment. Structure of the Co complex was optimized by DFT calculation. Solution-phase complexation between the ligand and the three metals ions: Mn+2, Co+2, and Ni+2 (pH 7.2 in tris buffer), in CH3CN–H2O was performed spectrophotometrically by UV–vis spectral study. Job’s plot from each titration suggests a 1 : 2 metal to ligand combination. The association constants for the formation of ML2 are as follows: Mn (19.80 × 103 M?1), Co (14.54 × 103 M?1) and Ni (19.04 × 103 M?1).  相似文献   

13.
Grafting of methyl methacrylate (MMA) onto delignified Grewia optiva fiber using ascorbic acid/H2O2 as an initiator was carried out under microwave irradiation. The effects of varying the microwave power, exposure time, and concentration of initiator and monomer of graft polymerization were studied to obtain maximum grafting percentage (26.54%). The experimental results showed that the optimal conditions for grafting were: exposure time, 10min; microwave power, 110 W; ascorbic acid concentration, 3.74mol/L × 10?2; H2O2 concentration, 0.97mol/L × 10?1; monomer concentration, 1.87mol/L × 10?1. The graft copolymers were characterized by Fourier transform-infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA).  相似文献   

14.
Novel poly(methyl methacrylate-co-methacrylic acid) (PMMAMA) and polyamide 6 (PA-6) blend was reinforced with graphene oxide (GO) and montmorillonite-modified GO (GO-MMT). In this way, two series of composites were prepared with varying GO and GO-MMT content. PA-6 was in situ polymerized and the effect of filler addition on molecular weight was studied using GPC. In the case of GO-MMT system, the lowering in molecular weight was more pronounced (Mn ~ 15 × 103 gmol?1). The thermal stability of PMMAMA/PA-6/GO-MMT 0.5–5 system was found higher than PMMAMA/PA-6/GO 0.5–5. PHHR of PMMAMA/PA-6/GO-MMT was decreased from 317 to 214 kW/m2 with 0.5–5 wt% loading.  相似文献   

15.
Coordination compounds having formulae [M(MA)3] n and M(MA)(Me2Tp)2 (M = Y, Eu, Tb; MA = conjugate base of malonaldehyde; Me2Tp = tris(3,5-dimethyl-pyrazol-1-yl)borate) were synthesized and characterized. The photoluminescence features of the europium and terbium derivatives were investigated. By comparing the herein reported photoluminescence data with those relative to analogous nitro- and bromomalonaldehyde derivatives, it appears that the conjugate base of malonaldehyde is a more efficient antenna-ligand for the sensitization of Tb(III) luminescence. The experimental data were rationalized on the basis of DFT calculations. Tb(MA)(Me2Tp)2 was used as dopant for the preparation of luminescent plastic materials based on poly(methyl methacrylate).  相似文献   

16.
Reactions of cobalt(II) nitrate or zinc(II) nitrate, tetrasodium p-sulfonatothiacalix[4]arene (Na4H4TCAS), and methylviologen dihexafluorophosphate (MV(PF6)2) afforded two isomorphous complexes, {[M(H2O)6]2 + [MV]2 + [(MV)2M2(H2O)4(H2TCAS)2]4 ? }·14H2O (M = Co, 1; Zn, 2). In these two complexes, each two thiacalixarenes form a dimer with C i symmetry through the coordination of sulfonate groups, and the above dimers further extend their structures through second-sphere coordination and π…π stacking interactions into three-dimension nets.  相似文献   

17.
Abstract

Acid-base equilibrium of the “one-face”-hindered sulfonated porphyrin, α5,15-[2,2′(dodecamethyleneoxy),(5-sulfonato)diphenyl]-10,20-bis(2-hydroxy,5-sulfonatophenyl)porphyrinato iron(III), has been studied by paramagnetic 1H NMR. The isotropically shifted signals change in a fast exchange regime on the NMR time-scale. 1H longitudinal relaxation times and temperature dependence of the chemical shifts were measured and analyzed. The electronic structure of hydroxo specie is characteristic of a six- or five-coordinate high-spin iron(III) porphyrin with an S = 5/2 ground state. The 1H NMR titration allowed determination of the acidity constant, pKa 6.2 (0.1 M KNO3, 25 °C). In addition, we also report the interaction between the monohydroxo iron(III) porphyrin and the bovine serum albumin protein. From a 1H NMR titration, we have determined the affinity apparent constant, log Kap 3.2 (pH 7, KNO3 0.1 M, 25 °C). The formation of superstructured iron porphyrin-albumin protein adduct was confirmed by electronic absorption spectroscopy and electron paramagnetic resonance.  相似文献   

18.
Lippia thymoides (‘alecrim-do-mato’ or ‘alecrim-do-campo’) is used in Brazilian folk medicine to treat various illnesses, including diarrhea. This work aimed to evaluate in vitro spasmolytic and in vivo antidiarrheal activities of the L. thymoides essential oil (OOS) and to correlate with the traditional use of this plant. In isolated guinea-pig ileum, OOS presented a concentration-dependent spasmolytic activity in preparations pre-contracted with KCl 40 mM [EC50 = 16.89 (11.56–24.66) μg/mL], and antagonized phasic contractions induced by 1 μM carbachol [IC50 = 42.71 (37.35–48.83) μg/mL] or histamine [IC50 = 32.38 (27.44–38.20) μg/mL]. In mice, OOS at 400 mg/kg reduced intestinal transit, at 200 and 400 mg/kg reduced total stool mass and at 400 mg/kg reduced intestinal fluid accumulation. It was shown that the antidiarrheal effect of OOS is related to the inhibition of smooth muscle contraction and may be due to the presence of major compound β-caryophyllene in this essential oil.  相似文献   

19.
《Analytical letters》2012,45(5):818-830
A facile strategy to construct an amperometric biosensor was described for the determination of hydrogen peroxide (H2O2). This biosensor relied on an electrospinning gold nanoparticle-chitosan-poly(vinyl alcohol) composite nanofibers modified ITO electrode, followed by immobilization of hemoglobin (Hb) on the surface. The introduction of nanofibers and gold nanoparticles in the modification of electrode surface not only enhanced the surface area of the modified electrode for enzyme immobilization but also facilitated the electron transfer rate. Under optimum conditions, the sensor was characterized in terms of its morphology by scanning electron microscopy and its electroactivity by cyclic voltammetry and chronoamperometry. Scanning electron microscopy revealed that the obtained nanofibers were uniform. The chronoamperometric behavior of the modified electrode indicated that the immobilized Hb retained electrochemical activity inside the electrospinning fibrous membranes. The electrode responded linearly to H2O2 in a wider concentration range of 5.6 × 10?7 M to 5.2 × 10?2 M with a low detection limit (S/N = 3) of 1.98 × 10?7 M and a short response time of ~4 s, suggesting a much better performance than that of other sensors. Moreover, the biosensor achieved bulk production and exhibited superior properties for the sensitive determination of H2O2, studied namely, long-term stability, good reproducibility, and high selectivity.  相似文献   

20.
Abstract

In this study, graft polymerization of 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS) on poly(ethylene terephthalate) (PET) films using cerium ammonium nitrate (CeAN) as an initiator was investigated. Before the polymerization reaction was carried out, films were swelled in dimethyl sulfoxide (DMSO) at 140°C for 1 h. The effect of polymerization temperature, time, initiator, and monomer concentrations on the graft yield were investigated. It was observed that the graft yield was initially increased with increasing temperature, monomer, and initiator concentrations; and then decreased. Graft yield was found to increase with increasing polymerization time up to 5 h, then remain constant. The effects of monomer and initiator inclusions on the grafting yield were also examined. Optimum conditions for grafting were found to be [AMPS] = 1.0 M, [Ce4+] = 1.5 × 10?2 M, T = 85°C and t = 5 h. The rate of grafting was found to be proportional to the 0.1 and 0.4 powers of monomer and initiator concentrations, respectively. The overall activation energy for the grafting was calculated to be 11.4 kcal mol?1. The effect of grafting on PET film properties such as intrinsic viscosity and water absorption capacity were determined. The grafted PET films were characterized with FTIR spectroscopy and scanning electron microscopy (SEM).  相似文献   

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