Triazole derivatives as corrosion inhibitors for mild steel in hydrochloric acid solution

The title compounds 1-（4,5-dihydro-3-phenyl pyridine-1-yl）-2-（1H-1,2,4-triazole-1-yl） ethyl ketones were studied as a corrosion inhibitor in a mild steel in 1 mol /L hydrochloric acid solution using weight loss measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy （EIS）. Results indicated that these compounds had excellent inhibition properties. Polarization curves indicated that the inhibitor behaved mainly as mixed-type inhibitor. The EIS results showed that the charge transfer controlled the corrosion process in the uninhibited and inhibited solutions. Adsorption of the inhibitor on the mild steel surface followed Langmuir＇s adsorption isotherm with negative value of the free energy of adsorption ΔGads^o. The thermodynamic parameters of adsorption were determined and discussed.

Benevolent behavior of Kleinia grandiflora leaf extract as a green corrosion inhibitor for mild steel in sulfuric acid solution

The ethanolic extract of Kleinia grandiflora leaves was characterized and tested for its potential anticorrosion properties on mild steel in 1 M H2SO4 medium using mass-loss analysis, potentiodynamic polarization measurements, electrochemical impedance spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, UV–visible spectroscopy, and X-ray diffraction analysis. The effect of temperature on the corrosion behavior of mild steel was studied in the range of 308 to 328 K. The inhibition efficiency was observed to increase with increasing concentration of the extract. Polarization curves revealed that the Kleinia grandiflora leaf extract is a mixed inhibitor. Impedance diagrams revealed that an increase of Kleinia grandiflora leaf extract concentration increased the charge transfer resistance and decreased the double-layer capacitance. The adsorption process obeys Langmuir＇s model, with a standard free energy of adsorption（ΔGads） of-18.62 k J/mol. The obtained results indicate that the Kleinia grandiflora leaf extract can serve as an effective inhibitor for the corrosion of mild steel in a sulfuric acid medium.

Efficiency of Chalcone Compounds Inhibitors for Acid Corrosion of Al and Al-3.5Mg Alloy

Corrosion inhibition of Al and Al-3.5Mg alloy by organic compounds, namely chalcones in hydrochloric acid solutions has been investigated by rapid polarization technique and weight loss method. Polarization measurements show that, the inhibitors act cathodically both in case of Al and Al-3.5Mg alloy. It was found from the weight loss measurements that, the inhibition efficiency depends on the substituent in the chalcone compound. The relative inhibitive efficiency of these compounds has been explained on the basis of structure dependent electron donor properties of the inhibitors and the metal inhibitor interaction on the surface. The inhibition efficiency ranges from 16 to 64% for Al and from 30% to 91% for Al-3.5Mg alloy

Effect of nitric oxide synthase inhibitor N^G-nitro-L-arginine on the content of amino acid in ischemic brain tissues of rats

BACKGROUND： Nitric oxide synthase （NOS） inhibrtors have been widely used to investigate the role of NO on cerebral ischemic injury, but the results are controversial. Moreover, it has been considered to aggravate the ischemic neuronal damage with the release of excessively excitatory amino acids （EAA） during cerebral ischemia. On the other hand, some inhibitory amino acid is suggested to be important for the neuronal protection against ischemic brain damage. Our study has recently showed that treatment with the NOS inhibitor NG-nitro-L-arginine （L-NA） reduced focal cerebral ischemic damage. The effect of L-NA on the contents of excitatory and inhibitory amino acid in the rat brain following cerebral ischemia is still unclear. OBJECTIVE： By evaluating the effect of NOS inhibitor, L-NA on the contents of aspartate, glutamate, glycine and γ-aminobutyric acid （GABA） in striatum, hippocampus and cortex in the rat brain following cerebral ischemia respectively, to investigate the beneficial effect of L-NA on cerebral ischemic injury and the possible mechanism. DESIGN： A randomized and controlled experiment SETTING ： Department of Pharmacology, Hebei Academy of Medical Sciences MATERIALS： A total of 42 male healthy SD rats （grade Ⅱ, weighting 250-300 g） were provided by the Experimental Animal Center of Hebei Province （Certification： 04036）. Aspartate, glutamate, glycine, GABA, L-NA and 2,3,5-triphenyltetrazolium chloride （TTC） were obtained from Sigma Chemicals Co, St Louis, MO, USA. HPLC-ultraviolet detector system consisted of Agilent 1100 HPLC. METHODS： The experiment was carried out in Department of Pharmrcology, Hebei Academy of Medical Sciences from June 2005 to June 2006. Rats were randomly divided into three groups： sham-operated group （n = 6）, ischemic group （n = 18）, L-NA group （n = 18）. The model of focal cerebral ischemia in rat was prepared with intraluminal line occlusion methods. In sham-operated rats, the external carotid artery was surgically prepared, but the filament was not inserted. Each group was further divided into 3 subgroups （n = 6 for each）： drugs were administrated at 2, 6 and 12 hours after the middle cerebral artery occlusion （MCAO） respectively. L-NA （20 mg/kg, ip） was administrated, twice a day, for 3 consecutive days. Same volume of normal saline was administrated in ischemic and sham operation groups. The changes of infarcted volume and the contents of amino acids were respectively assayed. Image analysis software was used for the measurement of the infarcted area. The results were expressed as a percentage of the infarcted volume of cerebral/volume of whole brain （IV%） in order to control for edema formation. The contents of aspartate, glutamate, glycine and GABA in striatum, hippocampus and cortex in the rat brain following cerebral ischemia were respectively measured by HPLC method. All data were analyzed with one-way ANOVA and Dunnett＇s test. MAIN OUTCOME MEASURES： （1） The volume of cerebral infarction; （2） The contents of aspartate, glutamate glycine and GABA in brain tissue after cerebral ischemia. RESULTS ： All 42 rats were involved in the final analysis. （1） Infarcted volume： Volume was 0 in sham-operated group. When L-NA was administrated at 2 and 6 hours after MCAO, the infarcted volume was （20.13±3.59）% and （23.12±5.84）% in L-NA group, which was not similar to that in ischemic group [（22.10±3.98）%, （25.38± 5.37）%, P〉 0.05]. However, the infarcted volume was markedly decreased compared with that of ischemic group when L-NA was administrated at 12 hours after MCAO [（26.11±3.55）% and （37.15±3.58）%, P 〈 0.01]. Changes of amino acid content： At 2 and 6 hours after ischemia, the contents of aspartate, glutamate, glycine and GABA in striatum, hippocampus and cortex in ischemic group were significantly increased compared with those in sham-operated group （ P〈 0.05-0.01）. However, contents in L-NA group were similar to those in ischemic group （P 〉 0.05）. At 12 hours after ischemia, the contents of aspartate [（0.21 ±0.06）, （0.36±0.05）, （0.29±0.12） mg/g] and glutamate [（0.55±0.06）, （0.78±0.10）, （0.52±0.10） mg/g] in striatum, hippocampus and cortex in L-NA group were significantly decreased compared with those in ischemic group [（0.49±0.17）, （0.63± 0.03）, （0.51±0.15） mg/g; （0.98±0.30）, （1.15±0.15）, （0.93±0.15） mg/g, P〈 0.05-0.01]. Glycine in hippocampus was （0.40±0.07） mg/g, which was higher than that in ischemic group [（0.21±0.07） mg/g, P 〈 0.05]. GABA in striatum, hippocampus and cortex was （0.93±0.10）, （0.62±0.12） and （0.81 ±0.10） mg/g, respectively, which was higher than that in ischemic group [（0.60±0.08）, （0.37±0.17）, （0.59±0.10） mg/g, P 〈 0.05-0.01]. CONCLUSION ： It may be concluded that L-NA have beneficial effect on ischemic cerebral injury in ischemic later stage in rats. The possible mechanism is that L-NA can decrease the contents of aspartate and glutamate, increase the contents of glycine and GABA.

Mechanical properties of hepatocellular carcinoma cells

AIM: To study the viscoelastic properties of human hepatocytes and hepatocellular carcinoma (HCC) cells under cytoskeletal perturbation, and to further to study the viscoelastic properties and the adhesive properties of mouse hepatoma cells (HTC) in different cell cycle. METHODS: Micropipette aspiration technique was adopted to measure viscoelastic coefficients and adhesion force to collagen coated surface of the cells. Three kinds of cytoskeleton perturbing agents, colchicines (Col), cytochalasin D (CD) and vinblastine (VBL), were used to treat HCC cells and hepatocytes and the effects of these treatment on cell viscoelastic coefficients were investigated. The experimental results were analyzed with a three-element standard linear solid. Further, the viscoelastic properties of HTC cells and the adhesion force of different cycle HTC cells were also investigated. The synchronous G(1) and S phase cells were achieved through thymine-2-desoryriboside and colchicines sequential blockage method and thymine-2-desoryriboside blockage method respectively. RESULTS: The elastic coefficients, but not viscous coefficient of HCC cells (K(1)=103.6+/-12.6N.m(-2), K(2)=42.5 +/ 10.4N.m(-2), mu=4.5 +/- 1.9Pa.s), were significantly higher than the corresponding value for hepatocytes (K(1)=87.5 +/- 12.1N.m(-2), K(2)=33.3+/-10.3N.m(-2), mu=5.9+/-3.0Pa.s, P【0.01). Upon treatment with CD, the viscoelastic coefficients of both hepatocytes and HCC cells decreased consistently, with magnitudes for the decrease in elastic coefficients of HCC cells (K(1): 68.7 N.m(-2) to 81.7N.m(-2), 66.3% to 78.9%; K(2): 34.5N.m(-2) to 37.1N.m(-2), 81.2% to 87.3%, P【0.001) larger than those for normal hepatocytes (K(1): 42.6N.m(-2) to 49.8N.m(-2), 48.7% to 56.9%; K(2): 17.2N.m(-2) to 20.4N.m(-2), 51.7% to 61.3%, P【0.001). There was a little decrease in the viscous coefficient of HCC cells (2.0 to 3.4Pa.s, 44.4 to 75.6%, P【0.001) than that for hepatocytes (3.0 to 3.9Pa.s, 50.8 to 66.1% P【0.001). Upon treatment with Col and VBL, the elastic coefficients of hepatocytes generally increased or tended to increase while those of HCC cells decreased. HTC cells with 72.1% of G(1) phase and 98.9% of S phase were achieved and high K(1), K(2) value and low mu value were the general characteristics of HTC cells. G(1) phase cells had higher K(1) value and lower mu value than S phase cells had, and G(1) phase HTC cells had stronger adhesive forces ((275.9 +/- 232.8) x 10(-10)N) than S phase cells ((161.2 +/- 120.4) x 10(-10)N, P【0.001). CONCLUSION: The difference in both the pattern and the magnitude of the effect of cytoskeletal perturbing agent on the viscoelastic properties between HCC cells and hepatocytes may reflect differences in the state of the cytoskeleton structure and function and in the sensitivity to perturbing agent treatment between these two types of cells. Change in the viscoelastic properties of cancer cells may affect significantly tumor cell invasion and metastasis as well as interactions between tumor cells and their micro-mechanical environments.

Regulation of fatty acid synthase on tumor and progress in the development of related therapies

Fatty acid synthase(FASN)is an essential molecule in lipid metabolic pathways,which are crucial for cancer-related studies.Recent studies have focused on a comprehensive understanding of the novel and important regulatory effects of FASN on malignant biological behavior and immune-cell infiltration,which are closely related to tumor occurrence and development,immune escape,and immune response.FASN-targeting antitumor treatment strategies are being developed.Therefore,in this review,we focused on the effects of FASN on tumor and immune-cell infiltration and reviewed the progress of related antitumor therapy development.

Synthesis and biological evaluation of echinocystic acid derivatives as HCV entry inhibitors

A series of echinocystic acid （EA） 28-COOH derivatives was synthesized, and their anti-HCV entry activity was evaluated by HCVpp and VSVpp entry assay. It was found that some of them showed moderate anti-HCV entry activity, especially compound 12, and these modifications also removed the undesired hemolytic effect.

Design,synthesis,and screen of cathepsin K inhibitors

We synthesized a series of epoxysuccinic acid derivatives and evaluated their in vitro cathepsin K inhibitory activity The screening results show that the potency of compounds 9e,9d,9p,9j and 9k （IC_（50）≤0.005μmol/L） were equal to or greater than that of the lead compound 9a.Less hydrophobic compounds showed weaker potency,which can be explained by the hydrophobic nature of the cathepsin K binding pockets.

Metal complexes of anthranilic acid derivatives: A new class of noncompetitive α-glucosidase inhibitors

Metal complexes of anthranilic acid derivatives that constitute a novel class of non-sugar-type α- glucosidase inhibitors were synthesized and assessed in vitro for inhibitory activity. All of the AgO） complexes （9-16） inhibited α-glucosidase at the nanomolar scale, while 3,5-dichloroanthranilic acid silver（1） （9） was the most potent （ICso = 3.21 nmol/L）. Analysis of the kinetics of enzyme inhibition indicated that the mechanism of the newly prepared silver complexes was noncompetitive. The structure-activity relationships were also analyzed, and thev are discussed in this report.

The amino acid sequence of a double-headed trypsin inhibitor from the seeds of Momordica charantia Linn.Cucurbitaceae

A double-headed trypsin inhibitor(MCI-1)was isolated and purified from the seeds of Momordica charantia Linn.Cucurbitaceae,by using the trypsin-sepharose-4B affinity chroma- tography and CM-Sephadex-C50 ion exchange chromatography.It is composed of 77 amino acid residues:Asp_8 Thr_1 Ser_4 Glu_8 Pro_2 Gly_6 Ala_4 Cys_(14) Val_2 Met_4 Ile_8 Leu_1 Phe_1 His_3 Lys_ Arg_7. The amino acid sequence of MCI-1 was determined by sequencing the cyanogen bromide,tryptic and staphylococcus aureus V8 proteolytic peptides,then aligned by overlapped sequences.The result shows that MCI-1 contains 7 pairs of disulfide bonds,its sequence showed the high homology with those of “Bowman-Birk”inhibitors.About 50% trypsin inhibitory activity still remained after MCI-1 was cleavaged with cyanogen bromide.