目的建立卡西酮、甲卡西酮、4-甲基甲卡西酮的LC-MS/MS定性定量分析方法。方法采用Agilent6460三重串联四极杆液质联用仪(LC/QQQ),样品用甲醇直接提取,采用Agilent Zorbax○R Eclipse Plus C18色谱柱(100mm×2.1mm,1.8μm),流动相为...目的建立卡西酮、甲卡西酮、4-甲基甲卡西酮的LC-MS/MS定性定量分析方法。方法采用Agilent6460三重串联四极杆液质联用仪(LC/QQQ),样品用甲醇直接提取,采用Agilent Zorbax○R Eclipse Plus C18色谱柱(100mm×2.1mm,1.8μm),流动相为0.1%甲酸和乙腈,梯度洗脱,流速为0.3mL/min,进样体积为3μL。质谱应用ESI源、正离子模式、多反应监测(MRM)方式检测卡西酮、甲卡西酮、4-甲基甲卡西酮。结果卡西酮的线性范围为1ng/mL^25000ng/mL,甲卡西酮的线性范围为0.1ng/mL^10000ng/mL,4-甲基甲卡西酮的线性范围为1ng/mL^10000ng/mL。结论该方法简单、准确,灵敏度高,可以满足案件鉴定工作的需要。展开更多
Interaction of amphetamine,cathine and cathinone with the enzyme dihydrofolate reductase was studied by molecular docking using AutoDock 4.2 as the docking software application.AutoDock 4.2 software serves as a valid ...Interaction of amphetamine,cathine and cathinone with the enzyme dihydrofolate reductase was studied by molecular docking using AutoDock 4.2 as the docking software application.AutoDock 4.2 software serves as a valid and acceptable docking application to study the interactions of small compounds with proteins.Interactions of amphetamine,cathine and cathinone with dihydrofolate reductase were compared to those of methotrexate,a known inhibitor of the enzyme.The calculated free energy of binding(ΔG binding)shows that the three ligands(ΔG=-6.87 to-7.21 kcal/mol;Ki=9.15 to 5.18μM)bind with affinity slightly lower than methotrexate(ΔG=-8.78 kcal/mol;Ki=363 nM).Binding interactions of the three ligands with active site residues of the enzyme are also predicted.All the ligands appear to bind in a similar conformation making extensive VDW contacts in the active site of the enzyme.Hydrogen bonding and pi-pi interaction with key active site residues is also observed.Thus,a probable inhibition of dihydrofolate reductase by khat alkaloids can be explained on the basis of this in silico binding and khat alkaloids can be considered as potential lead compounds in the development of new inhibitors of dihydrofolate reductase which is a potential target of anti-cancer drugs.The results of these studies can serve as a starting point for further computational and experimental studies.展开更多
文摘目的建立卡西酮、甲卡西酮、4-甲基甲卡西酮的LC-MS/MS定性定量分析方法。方法采用Agilent6460三重串联四极杆液质联用仪(LC/QQQ),样品用甲醇直接提取,采用Agilent Zorbax○R Eclipse Plus C18色谱柱(100mm×2.1mm,1.8μm),流动相为0.1%甲酸和乙腈,梯度洗脱,流速为0.3mL/min,进样体积为3μL。质谱应用ESI源、正离子模式、多反应监测(MRM)方式检测卡西酮、甲卡西酮、4-甲基甲卡西酮。结果卡西酮的线性范围为1ng/mL^25000ng/mL,甲卡西酮的线性范围为0.1ng/mL^10000ng/mL,4-甲基甲卡西酮的线性范围为1ng/mL^10000ng/mL。结论该方法简单、准确,灵敏度高,可以满足案件鉴定工作的需要。
文摘Interaction of amphetamine,cathine and cathinone with the enzyme dihydrofolate reductase was studied by molecular docking using AutoDock 4.2 as the docking software application.AutoDock 4.2 software serves as a valid and acceptable docking application to study the interactions of small compounds with proteins.Interactions of amphetamine,cathine and cathinone with dihydrofolate reductase were compared to those of methotrexate,a known inhibitor of the enzyme.The calculated free energy of binding(ΔG binding)shows that the three ligands(ΔG=-6.87 to-7.21 kcal/mol;Ki=9.15 to 5.18μM)bind with affinity slightly lower than methotrexate(ΔG=-8.78 kcal/mol;Ki=363 nM).Binding interactions of the three ligands with active site residues of the enzyme are also predicted.All the ligands appear to bind in a similar conformation making extensive VDW contacts in the active site of the enzyme.Hydrogen bonding and pi-pi interaction with key active site residues is also observed.Thus,a probable inhibition of dihydrofolate reductase by khat alkaloids can be explained on the basis of this in silico binding and khat alkaloids can be considered as potential lead compounds in the development of new inhibitors of dihydrofolate reductase which is a potential target of anti-cancer drugs.The results of these studies can serve as a starting point for further computational and experimental studies.
