Electrochemical Recognition Of Rutin And Its Effect On Spectral Properties Of Glycosylated Serum Albumin

The quantitative analysis of drugs is particularly important,whether it is the detection of drug content in vitro or the study of pharmacokinetics in vivo.Here,a new electrochemical sensor system was constructed for the high-sensitivity detection of rutin（Ru）,combining the excellent conductivity of multi-walled carbon nanotubes（MWCNTs）and Fe₃O₄nanoparticles（Fe₃O₄）and the film-forming property ofβ-cyclodextrin（CD）,on a glassy carbon electrode（GCE）.From the results of transmission electron microscope,MWCNTs,Fe₃O₄ and CD formed a functional composite film,and CD played a certain role in the film formation of MWCNTs and Fe₃O₄.The structure of Ru was studied by UV spectrophotometer,and two absorption peaks obtained were benzoyl and cinnamoyl structures of Ru,respectively.The electrochemical properties of MWCNTs-CD-Fe₃O₄/GCE were studied by cyclic voltammetry and electrochemical impedance spectroscopy.TheΔE was 62 m V and the ratio of|Ipa/Ipc|was 0.95,indicating that the redox reaction of Ru on the electrode was quasi-reversible,and the electrode reaction of Ru redox was the two electrons accompanied by two protons process.At the same time,Ru was oxidized to quinones on the electrode.The MWCNTs-CD-Fe₃O₄/GCE responded to Ru was studied by differential pulse voltammetry.The detection range was 0.02-10μM and the detection limit was 16.4 n M.Compared with the results of ultra-high performance liquid chromatography,this method had good accuracy.The study also found that the prepared sensor not only had good anti-interference ability and storage stability,but also had a certain response to the similar structures of flavanols,such as quercetin（Qu）.It will have a certain potential value for the simultaneous determination of flavanols similar materials and the study of pharmacokinetics in the future.In addition,the inhibition and structural protection of Ru on the non-enzymatic glycosylation of bovine serum albumin（BSA）were studied in vitro,from the aspects of the formation of advanced glycation end products（AGEs）and fructosamine,the hydrophobicity,aggregation state and secondary structure of protein by a variety of technical means such as fluorescence spectrophotometer,ultraviolet（UV）spectrophotometer and circular dichroism spectrometer.A glycosylated bovine serum albumin model was constructed to evaluate the anti-glycosylation ability of Ru in vitro.The study on inhibition of AGEs by Ru showed that the inhibition rates of 50,100 and250μM Ru were 26.5%,36.4%,41.3%,respectively.The study on the inhibition of fructosamine by Ru showed that the inhibition rates of 50,100,250μM Ru were 18.6%,24.4%,21.9%,respectively.The above two results showed that the presence of Ru could effectively inhibit the non-enzymatic glycosylation of BSA.The 8-Anilino-1-naphthalenesulfonic acid ammonium salt（ANS）and nile red（NR）fluorescent dyes were used to study the changes of protein hydrophobicity,and the results showed that Ru could weaken the ANS and NR fluorescence intensity of glycosylated BSA,and improve the exposure of protein hydrophobic region.Thioflavin T（Th T）fluorescent dye method was used to study protein aggregation.The results showed that the Th T fluorescence intensity of glycosylated BSA could be reduced in the presence of Ru,indicating that Ru could effectively prevent the formation of amyloid.The results of circular dichroism spectrum showed that in the presence of high glucose,the content ofα-helix structure of BSA was reduced to 45.8%,while in the presence of Ru the content ofα-helix structure was increased.The contents ofα-helix structure of BSA in the presence of 50,100 and 250μM Ru changed to 52.2%,51.4%,48.2%,respectively.The results showed that Ru can act as effective anti-aggregation agents to resist the secondary structural changes of BSA induced by glucose.Molecular docking method was used to simulate the action sites of Ru and BSA.The results of molecular docking showed that the main action sites of BSA-Ru were PRO415,GLN416,THR495,TYR496,VAL497,LYS533.In conclusion,Ru electrochemical sensor may be used in blood drug concentration monitoring.Ru have the function of inhibiting protein non-enzymatic glycation and protecting protein structure in vitro,which may be used to improve diabetes and its complications.