The Inhibitory Effects Of Polyoxometalates And Two Antioxidants On α-Glucosidase

α-Glucosidase is involved in the digestion and absorption of carbohydrates such as starch and sucrose.By inhibiting the activity of α-glucosidase can effectively reduce or control blood sugar levels.At present,classic α-glucosidase inhibitors include acarbose,miglitol,and voglibose.With the continuous deepening of scientific research,the types of α-glucosidase inhibitors are becoming more and more abundant,but there are various side effects.Therefore,it is very important to continuously search for safe and efficient α-glucosidase inhibitors.Polyoxometalates have biological characteristics such as structural diversity and unique properties.The research achievements of polyoxometalates have been outstanding in biomedicine.Polyoxometalates have the functions of inhibiting enzyme activity,bacteriostasis,antiviral,anti-tumor and so on.Antioxidants are food additives that prevent or delay food oxidation,improve food stability and prolong storage period.This article mainly studies the inhibitory effect and mechanism of polyoxometalates and antioxidants on α-glucosidase,respectively.(1)Synthesis and characterization of transition metal vanadium substituted Keggin series phosphomolybdic acid H3+nPMo12-nVnO40(n=1,2,3,4,5).The molecular docking technology and enzyme kinetics were used to study the inhibitory effect of synthetic compounds onα-glucosidase.The results showed that PMo9V3 had the best inhibitory effect on α-glucosidase,with an IC50 value of 9.639±0.432 μM.This series of Keggin-type phosphomolybdic acid showed reversible mixed inhibition of α-glucosidase.The molecular docking results show that the ligand compound and α-glucosidase are bound by hydrogen bonding and van der Waals non-valence interaction.(2)Phosphomolybdic acid H8[P2Mo18O62]and a series of transition metal-substituted Dawson series phosphomolybdic acids H8PMo17MO61(M=Cr,Cu,Mn,Fe,Co,Ni,Zn)were synthesized,and the structure was characterized by spectrophotometry.Through molecular enzyme dynamics and molecular docking methods,the inhibitory effect of compounds onα-glucosidase,the mechanism of inhibition,the type of inhibition,and the interaction between ligand compounds and enzyme proteins were explored.The results showed that P2Mo17Cr and P2Mo17Fe showed reversible competitive inhibition of α-glucosidase,and other phosphomolybdic acids showed a reversible mixed inhibition.The results of molecular docking show that the ligand compound interacts with α-glucosidase through non-valid bonds such as hydrogen bonds and van der Waals forces.(3)A series of wheel-shaped molybdenum clusters were synthesized and characterized.The inhibitory effect of molybdenum clusters on α-glucosidase was studied by enzymatic method.The results showed that Mo57Fe6 had the best inhibitory effect on α-glucosidase,and its IC50 value reached 0.0259 ±0.000328 mM.Mo57Fe6,Mo57Mn6 and Mo57V6 were reversible mixed-type inhibition of α-glucosidase.However,Mo36 had a reversible competitive inhibition of α-glucosidase.Through molecular docking simulation,it was found that large molecular weight of molybdenum clusters,it was impossible to dock with the constructed α-glucosidase.(4)To study the inhibitory effects of phytic acid and L-ascorbyl palmitate on α-glucosidase,respectively.The results of enzyme kinetics showed that L-ascorbyl palmitate had a better inhibitory effect on α-glucosidase,and its inhibition type was reversible competitive inhibition.The inhibitory type of phytic acid on α-glucosidase is reversible mixed inhibition.The molecular docking results show that the two compounds can interact well with amino acids in the active site of α-glucosidase.