The interaction of baicalein with bovine serum albumin（BSA） was investigated with the help of spectroscopic and molecular docking studies.The binding affinity of baicalein towards BSA was estimated to be in order of...The interaction of baicalein with bovine serum albumin（BSA） was investigated with the help of spectroscopic and molecular docking studies.The binding affinity of baicalein towards BSA was estimated to be in order of 10~5 M^（-1） from fluorescence quenching studies.Negative ΔH°（-5.66 ＋ 0.14 kJ/mol） and positive（ΔS°）（＋ 79.96 ＋ 0.65J/mol K） indicate the presence of electrostatic interactions along with the hydrophobic forces that result in a positive ΔS°.The hydrophobic association of baicalein with BSA diminishes in the presence of sodium dodecyl sulfate（SDS） due to probable hydrophobic association of baicalein with SDS,resulting in a negative ΔS°（-40.65 ＋ 0.87 J/mol K）.Matrix-assisted laser desorption ionization/time of flight（MALDI-TOF） experiments indicate a 1：1 complexation between baicalein and BSA.The unfolding and refolding phenomena of BSA were investigated in the absence and presence of baicalein using steady-state and fluorescence lifetime measurements.It was observed that the presence of urea ruptured the non-covalent interaction between baicalein and BSA.The presence of metal ions（Ag~＋,Mg^（2＋）,Ni^（2＋）,Mn^（2＋）,Co^（2＋） and Zn^（2＋）） increased the binding affinity of ligand towards BSA.The changes in conformational aspects of BSA after ligand binding were also investigated using circular dichroism（CD） and Fourier transform infrared（FT-IR） spectroscopic techniques.Site selectivity studies following molecular docking analyses indicated the binding of baicalein to site 1（subdomain MA） of BSA.展开更多
Three new acylhydrazones containing pyrazine ring(C12H11N5O2·CH3COOH,1;C13H13N5O·2CH3COOH,2;C13H13N5O3·C13H13N5O3,3)were synthesized and fully characterized.The single-crystal XRD indicated that both 1 ...Three new acylhydrazones containing pyrazine ring(C12H11N5O2·CH3COOH,1;C13H13N5O·2CH3COOH,2;C13H13N5O3·C13H13N5O3,3)were synthesized and fully characterized.The single-crystal XRD indicated that both 1 and 2 crystallized in monoclinic,P21/c space group but 3 belonged to monoclinic,C2/c space group.The temperature of the maximum thermal decomposition peaks measured by thermogravimetry for 1~3 is 284,289 and 276℃respectively,all showing better thermal stabilities.The interactions of 1~3 with calf thymus DNA(CT-DNA)and bovine serum albumin(BSA)were studied by UV-Vis absorption spectroscopy and fluorescence spectroscopy,respectively,presenting that 1~3 could bind to CT-DNA via groove binding mode and quench the fluorescence of BSA through static process.Moreover,molecular docking studies of the interactions between 1~3 with DNA/BSA were in good agreement with experimental results.From antimicrobial activities of 1~3 and gentamycin sulfate against Staphylococcus aureus,Escherichia coli and Salmonella typhimurium,it was inferred that 3 had generally stronger antibacterial activity than 1 and 2 and is more active against Staphylococcus aureus than gentamycin sulfate.The cytotoxic tests of 1~3 and etoposide on human lung cancer cells(A549)were carried out by using the MTT method.展开更多
基金Department of Science and Technology(DST,Project no.SR/SO/BB-54/2007),Government of India for financial support
文摘The interaction of baicalein with bovine serum albumin（BSA） was investigated with the help of spectroscopic and molecular docking studies.The binding affinity of baicalein towards BSA was estimated to be in order of 10~5 M^（-1） from fluorescence quenching studies.Negative ΔH°（-5.66 ＋ 0.14 kJ/mol） and positive（ΔS°）（＋ 79.96 ＋ 0.65J/mol K） indicate the presence of electrostatic interactions along with the hydrophobic forces that result in a positive ΔS°.The hydrophobic association of baicalein with BSA diminishes in the presence of sodium dodecyl sulfate（SDS） due to probable hydrophobic association of baicalein with SDS,resulting in a negative ΔS°（-40.65 ＋ 0.87 J/mol K）.Matrix-assisted laser desorption ionization/time of flight（MALDI-TOF） experiments indicate a 1：1 complexation between baicalein and BSA.The unfolding and refolding phenomena of BSA were investigated in the absence and presence of baicalein using steady-state and fluorescence lifetime measurements.It was observed that the presence of urea ruptured the non-covalent interaction between baicalein and BSA.The presence of metal ions（Ag~＋,Mg^（2＋）,Ni^（2＋）,Mn^（2＋）,Co^（2＋） and Zn^（2＋）） increased the binding affinity of ligand towards BSA.The changes in conformational aspects of BSA after ligand binding were also investigated using circular dichroism（CD） and Fourier transform infrared（FT-IR） spectroscopic techniques.Site selectivity studies following molecular docking analyses indicated the binding of baicalein to site 1（subdomain MA） of BSA.
基金supported by the National Natural Science Foundation of China(Nos.U1903033,21073139 and 21373158)Science and Technology on Combustion and Explosion Laboratory Foundation of Shaanxi(No.6142603010301)。
文摘Three new acylhydrazones containing pyrazine ring(C12H11N5O2·CH3COOH,1;C13H13N5O·2CH3COOH,2;C13H13N5O3·C13H13N5O3,3)were synthesized and fully characterized.The single-crystal XRD indicated that both 1 and 2 crystallized in monoclinic,P21/c space group but 3 belonged to monoclinic,C2/c space group.The temperature of the maximum thermal decomposition peaks measured by thermogravimetry for 1~3 is 284,289 and 276℃respectively,all showing better thermal stabilities.The interactions of 1~3 with calf thymus DNA(CT-DNA)and bovine serum albumin(BSA)were studied by UV-Vis absorption spectroscopy and fluorescence spectroscopy,respectively,presenting that 1~3 could bind to CT-DNA via groove binding mode and quench the fluorescence of BSA through static process.Moreover,molecular docking studies of the interactions between 1~3 with DNA/BSA were in good agreement with experimental results.From antimicrobial activities of 1~3 and gentamycin sulfate against Staphylococcus aureus,Escherichia coli and Salmonella typhimurium,it was inferred that 3 had generally stronger antibacterial activity than 1 and 2 and is more active against Staphylococcus aureus than gentamycin sulfate.The cytotoxic tests of 1~3 and etoposide on human lung cancer cells(A549)were carried out by using the MTT method.
