A rapid, novel spectrofluorimetric method to determine epristeride （EP） in biological fluids and a pharmaceutical formulation was developed, based on the fact that fluorescence intensity of L-tryptophan could be que...A rapid, novel spectrofluorimetric method to determine epristeride （EP） in biological fluids and a pharmaceutical formulation was developed, based on the fact that fluorescence intensity of L-tryptophan could be quenched by EP in the medium of pH=9.0. The various factors influencing fluorescence quenching were discussed. The quenching mechanism was investigated with the quenching type, synchronous fluorescence spectra and quantum efficiency. Under the optimized conditions, fluorescence quenching value （AF^---FL_tryptophan--FEP_L_tryptophan） showed a good linear relationship with the EP concentration ranging from 0.4 to 12.0 lag/mL. The linearity, recovery and limit of detection demonstrated that the proposed method was suitable for EP determination in biological fluids and EP tablets. The method was successfully applied to the analysis of EP in real samples and the obtained results were in good agreement with the results of the official method.展开更多
In this paper, we describe a simple and efficient synthesis of gold nanoparticles(GNPs) of various shapes(spherical, rod-like, hexagonal, truncated triangular, and triangular) using Au(Ⅲ) reduction in aqueous solutio...In this paper, we describe a simple and efficient synthesis of gold nanoparticles(GNPs) of various shapes(spherical, rod-like, hexagonal, truncated triangular, and triangular) using Au(Ⅲ) reduction in aqueous solutions by L-tryptophan. We evaluated the influences of reaction temperature, foreign metal ions Ag(Ⅰ), and surfactants of nonionic(polyethylene glycol, PEG), anionic(sodium dodecyl sulfate, SDS), and cationic(cetyltrimethyl ammonium bromide, CTAB) on GNPs synthesis. We characterized the resultant GNPs using UV–visible adsorption spectroscopy, transmission electron microscopy/high-resolution transmission electron microscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, selected-area electron diffraction, and Fourier-transform infrared spectroscopy. We fabricated the variously sized GNPs by controlling the rate of the reduction of gold ions in aqueous solution by varying the reaction temperature: the higher the temperature, the smaller the gold nanospheres. We found the existence of Ag(Ⅰ) to reinforce the reduction of Au(Ⅲ) and to correspond with the appearance of some amorphous bimetallic Au/Ag nanoparticles. Additionally, we found the presence of surfactants to greatly influence the shape of the formed GNPs, especially the presence of CTAB, which results in the anisotropic growth of gold nanocrystals into hexagonal, truncated triangular, and triangular nanoplates. In addition, with the increase in CTAB concentration, we found the amount of gold nanoplates to first increase and then decrease. Finally, we performed preliminary explorations of the reduction process and morphological evolution to propose possible corresponding reduction and morphological evolution pathways.展开更多
5,11,17,23-Tetra-tert-butyl-25, 27-bis（7＇-methoxycoumarin-3＇-methyloxy）-26, 28-dihydroxycalix[4]arene was synthesized and characterized. The derivative could recognize L-tryptophan with a 1：1 complexing ratio and...5,11,17,23-Tetra-tert-butyl-25, 27-bis（7＇-methoxycoumarin-3＇-methyloxy）-26, 28-dihydroxycalix[4]arene was synthesized and characterized. The derivative could recognize L-tryptophan with a 1：1 complexing ratio and an apparent equilibrium constant of 111 L mol^-1 in DMF acetonitrile as solvent by UV-visible and fluorescent spectrophotometry.展开更多
This study focuses on shape-controlled synthesis of gold nanoparticles, using the green reducing agent L-Tryptophan(L-Trp), which is non-toxic and eco-friendly. This specific agent was investigated to realize certain ...This study focuses on shape-controlled synthesis of gold nanoparticles, using the green reducing agent L-Tryptophan(L-Trp), which is non-toxic and eco-friendly. This specific agent was investigated to realize certain morphology controlling effects by changing the relative growth rates among various crystal planes. Experimental samples were characterized by transmission electron microscope, UV-Vis spectrophotometer and X-ray diffraction(XRD) for size and morphological information. The effects of the specific additives of PVP((C_6 H_9 NO)_n), CTAB(C_(16)H_(33)(CH_3)_3 NBr), and KBr were examined for their morphological control individually and synergistically in this system. Hexagonal gold nanoparticles were successfully obtained via the PVP/CTAB and PVP/KBr systems. Particular amounts of PVP/KBr produced various polyhedron structures, such as cubes, and others with triangular and rhombic straight-side cross sections.展开更多
The interactions between L-tryptophan（L-Trp） and water-soluble p-sulfonatocalix[4]- arene （SCX4） were investigated by spectrofluorometry. The effect of pH was discussed. The interaction process was estimated from ...The interactions between L-tryptophan（L-Trp） and water-soluble p-sulfonatocalix[4]- arene （SCX4） were investigated by spectrofluorometry. The effect of pH was discussed. The interaction process was estimated from the thermodynamic viewpoint. The SCX4 was found to be able to adjust its conformation to fit the size of L-Trp, and the benzene of L-Trp penetrated into the hydrophobic cavity of SCX4. Meanwhile, the binding mechanism was further elucidated by IHNMR and molecular mechanics calculations.展开更多
Two new L-tryptophan derivatives,（S）-2-（4-acetoxybenzamido）-3-（1 H-indol-3-yl）propanoic acid（I） and（S）-2-（3-acetoxybenzamido）-3-（1H-indol-3-yl）propanoic acid（II）, were synthesized and characterized by ...Two new L-tryptophan derivatives,（S）-2-（4-acetoxybenzamido）-3-（1 H-indol-3-yl）propanoic acid（I） and（S）-2-（3-acetoxybenzamido）-3-（1H-indol-3-yl）propanoic acid（II）, were synthesized and characterized by FT-IR, NMR and MS. The single crystals were cultivated and determined with X-ray diffraction. It was determined that the two compounds crystallized in monoclinic space group P21. Compound I（C（21）H（20）N2O5, Mr = 380.39） with a = 8.5227（6）, b = 7.8310（6）, c = 15.2527（11） A°, Z = 2, V = 1017.81（13） A°^3, μ = 0.090 mm^-1, Dc = 1.241 g/cm^3, F（000） = 400, the final R = 0.0412 and w R = 0.1170 for all data. Compound II（C（21）H（20）N2O5, Mr = 380.39） with a = 9.5112（5）, b = 9.2197（4）, c = 10.9115（5） A°, Z = 2, V = 952.13（8） A°^3, μ = 0.096 mm^-1, Dc = 1.327 g/cm^3, F（000） = 400, the final R = 0.0377 and w R = 0.1009 for all data. The anticoagulant activities of L-tryptophan derivatives were evaluated by plasma re-calcification time（PRT） and blood concretion four items（APTT, PT, TT and FIB）. The results exhibited that L-tryptophan derivatives showed anticoagulant activity in normal coagulation pathway.展开更多
The aim of this study was to determine the effect of pharmacological doses of melatonin (MEL) and L-tryptophan (L-TRP) on depression-like behavior in female rats submitted to the forced swimming test (FST) after 2, 4,...The aim of this study was to determine the effect of pharmacological doses of melatonin (MEL) and L-tryptophan (L-TRP) on depression-like behavior in female rats submitted to the forced swimming test (FST) after 2, 4, 6 or 8 weeks of treatment. This will allow exploring the different mechanisms of L-TRP actions particularly that due to its conversion into MEL. For this purpose, four groups of 24 rats each were constituted;(Group 1: Control): received saline solution NaCl (0.9%), (Group 2: MEL4): received 4 mg/Kg of MEL, (Group 3: L-TRP4): received 4 mg/Kg of L-TRP and (Group 4: L-TRP20): received 20 mg/Kg of L-TRP. Animals of each group were distributed on 4 subgroups of 6 rats submitted to different time treatments. The duration of immobility (TIM) and struggling period (TST) of rats in FST were measured after 2, 4, 6 and 8 weeks of drug treatment and the effects of MEL and L-TRP were compared. Chronical administration of different doses of MEL or L-TRP failed to induce any anti-depressant activity in rats subjected to FST after 2 weeks of treatment. However, after 4 weeks, daily administration of MEL at 4 mg/Kg significantly reduced the immobility period and enhanced struggling time. After 6 weeks, MEL at 4 mg/Kg and L-TRP at 20 mg/Kg were both effective in reducing immobility and increasing struggling movement, their effects being statistically comparable. All treatments were able to significantly reduce immobility time and increase struggling duration after 8 weeks, but L-TRP at 4 mg/Kg was less potent than MEL and L-TRP at 20 g/Kg. The antidepressant-like activity of L-TRP was dose and time dependent, and that of MEL was time dependent. In conclusion, the study showed that at pharmacological doses, MEL and L-TRP have anti-depressant action, and such effect is dependent on time treatment;MEL?is more effective than L-TRP. In conclusion, L-TRP, through MEL, 5-HT or by itself could modulate aminergic neurotransmission in the different brain areas to ensure its behavioral effects.展开更多
基金the financial support from the National Natural Science Foundation of China(20875082and 21155001)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Foundation of the Excellence Science and Technology Invention Team in Yangzhou University
文摘A rapid, novel spectrofluorimetric method to determine epristeride （EP） in biological fluids and a pharmaceutical formulation was developed, based on the fact that fluorescence intensity of L-tryptophan could be quenched by EP in the medium of pH=9.0. The various factors influencing fluorescence quenching were discussed. The quenching mechanism was investigated with the quenching type, synchronous fluorescence spectra and quantum efficiency. Under the optimized conditions, fluorescence quenching value （AF^---FL_tryptophan--FEP_L_tryptophan） showed a good linear relationship with the EP concentration ranging from 0.4 to 12.0 lag/mL. The linearity, recovery and limit of detection demonstrated that the proposed method was suitable for EP determination in biological fluids and EP tablets. The method was successfully applied to the analysis of EP in real samples and the obtained results were in good agreement with the results of the official method.
基金supported by the Independent Innovation Foundation of Tianjin University (No. 2016XZC-0028)
文摘In this paper, we describe a simple and efficient synthesis of gold nanoparticles(GNPs) of various shapes(spherical, rod-like, hexagonal, truncated triangular, and triangular) using Au(Ⅲ) reduction in aqueous solutions by L-tryptophan. We evaluated the influences of reaction temperature, foreign metal ions Ag(Ⅰ), and surfactants of nonionic(polyethylene glycol, PEG), anionic(sodium dodecyl sulfate, SDS), and cationic(cetyltrimethyl ammonium bromide, CTAB) on GNPs synthesis. We characterized the resultant GNPs using UV–visible adsorption spectroscopy, transmission electron microscopy/high-resolution transmission electron microscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, selected-area electron diffraction, and Fourier-transform infrared spectroscopy. We fabricated the variously sized GNPs by controlling the rate of the reduction of gold ions in aqueous solution by varying the reaction temperature: the higher the temperature, the smaller the gold nanospheres. We found the existence of Ag(Ⅰ) to reinforce the reduction of Au(Ⅲ) and to correspond with the appearance of some amorphous bimetallic Au/Ag nanoparticles. Additionally, we found the presence of surfactants to greatly influence the shape of the formed GNPs, especially the presence of CTAB, which results in the anisotropic growth of gold nanocrystals into hexagonal, truncated triangular, and triangular nanoplates. In addition, with the increase in CTAB concentration, we found the amount of gold nanoplates to first increase and then decrease. Finally, we performed preliminary explorations of the reduction process and morphological evolution to propose possible corresponding reduction and morphological evolution pathways.
基金financial supported by the Science Foundation of the Education Department of Hubei Province(Project Z200522002)the 0pen Foundation of Hubei Key Laboratory of Biotechnology in Traditional Chinese Medicine(Project 20040201).
文摘5,11,17,23-Tetra-tert-butyl-25, 27-bis（7＇-methoxycoumarin-3＇-methyloxy）-26, 28-dihydroxycalix[4]arene was synthesized and characterized. The derivative could recognize L-tryptophan with a 1：1 complexing ratio and an apparent equilibrium constant of 111 L mol^-1 in DMF acetonitrile as solvent by UV-visible and fluorescent spectrophotometry.
基金supported by the Independent Innovation Foundation of Tianjin University (No.2016XZC-0028)
文摘This study focuses on shape-controlled synthesis of gold nanoparticles, using the green reducing agent L-Tryptophan(L-Trp), which is non-toxic and eco-friendly. This specific agent was investigated to realize certain morphology controlling effects by changing the relative growth rates among various crystal planes. Experimental samples were characterized by transmission electron microscope, UV-Vis spectrophotometer and X-ray diffraction(XRD) for size and morphological information. The effects of the specific additives of PVP((C_6 H_9 NO)_n), CTAB(C_(16)H_(33)(CH_3)_3 NBr), and KBr were examined for their morphological control individually and synergistically in this system. Hexagonal gold nanoparticles were successfully obtained via the PVP/CTAB and PVP/KBr systems. Particular amounts of PVP/KBr produced various polyhedron structures, such as cubes, and others with triangular and rhombic straight-side cross sections.
基金supported by the National Natural Science Foundation of China(No.20575038).
文摘The interactions between L-tryptophan（L-Trp） and water-soluble p-sulfonatocalix[4]- arene （SCX4） were investigated by spectrofluorometry. The effect of pH was discussed. The interaction process was estimated from the thermodynamic viewpoint. The SCX4 was found to be able to adjust its conformation to fit the size of L-Trp, and the benzene of L-Trp penetrated into the hydrophobic cavity of SCX4. Meanwhile, the binding mechanism was further elucidated by IHNMR and molecular mechanics calculations.
基金supported by the National Natural Science Foundation of China(No.21362001)High Level Innovation Team and Outstanding Scholar Project of Guangxi High School(2014.No.49)
文摘Two new L-tryptophan derivatives,（S）-2-（4-acetoxybenzamido）-3-（1 H-indol-3-yl）propanoic acid（I） and（S）-2-（3-acetoxybenzamido）-3-（1H-indol-3-yl）propanoic acid（II）, were synthesized and characterized by FT-IR, NMR and MS. The single crystals were cultivated and determined with X-ray diffraction. It was determined that the two compounds crystallized in monoclinic space group P21. Compound I（C（21）H（20）N2O5, Mr = 380.39） with a = 8.5227（6）, b = 7.8310（6）, c = 15.2527（11） A°, Z = 2, V = 1017.81（13） A°^3, μ = 0.090 mm^-1, Dc = 1.241 g/cm^3, F（000） = 400, the final R = 0.0412 and w R = 0.1170 for all data. Compound II（C（21）H（20）N2O5, Mr = 380.39） with a = 9.5112（5）, b = 9.2197（4）, c = 10.9115（5） A°, Z = 2, V = 952.13（8） A°^3, μ = 0.096 mm^-1, Dc = 1.327 g/cm^3, F（000） = 400, the final R = 0.0377 and w R = 0.1009 for all data. The anticoagulant activities of L-tryptophan derivatives were evaluated by plasma re-calcification time（PRT） and blood concretion four items（APTT, PT, TT and FIB）. The results exhibited that L-tryptophan derivatives showed anticoagulant activity in normal coagulation pathway.
文摘The aim of this study was to determine the effect of pharmacological doses of melatonin (MEL) and L-tryptophan (L-TRP) on depression-like behavior in female rats submitted to the forced swimming test (FST) after 2, 4, 6 or 8 weeks of treatment. This will allow exploring the different mechanisms of L-TRP actions particularly that due to its conversion into MEL. For this purpose, four groups of 24 rats each were constituted;(Group 1: Control): received saline solution NaCl (0.9%), (Group 2: MEL4): received 4 mg/Kg of MEL, (Group 3: L-TRP4): received 4 mg/Kg of L-TRP and (Group 4: L-TRP20): received 20 mg/Kg of L-TRP. Animals of each group were distributed on 4 subgroups of 6 rats submitted to different time treatments. The duration of immobility (TIM) and struggling period (TST) of rats in FST were measured after 2, 4, 6 and 8 weeks of drug treatment and the effects of MEL and L-TRP were compared. Chronical administration of different doses of MEL or L-TRP failed to induce any anti-depressant activity in rats subjected to FST after 2 weeks of treatment. However, after 4 weeks, daily administration of MEL at 4 mg/Kg significantly reduced the immobility period and enhanced struggling time. After 6 weeks, MEL at 4 mg/Kg and L-TRP at 20 mg/Kg were both effective in reducing immobility and increasing struggling movement, their effects being statistically comparable. All treatments were able to significantly reduce immobility time and increase struggling duration after 8 weeks, but L-TRP at 4 mg/Kg was less potent than MEL and L-TRP at 20 g/Kg. The antidepressant-like activity of L-TRP was dose and time dependent, and that of MEL was time dependent. In conclusion, the study showed that at pharmacological doses, MEL and L-TRP have anti-depressant action, and such effect is dependent on time treatment;MEL?is more effective than L-TRP. In conclusion, L-TRP, through MEL, 5-HT or by itself could modulate aminergic neurotransmission in the different brain areas to ensure its behavioral effects.
