Study On Antioxidant Activity And Structure-activity Relationship Of Curcuminoids

Curcumin?CUR?is a natural polyphenol antioxidants which comes from the roots of turmeric,it is the main component of natural curcuminoids that CUR is homologous to food and medicine.In this study,CUR,DMC,BDMC,BIMC,and CURC were found through a series of reactions.The antioxidant activity of curcuminoids was evaluated by in vitro free radical scavenging and anti-lipid peroxidation experiments.Quantum chemistry theory calculated the ionization potential,bonding energy and other parameters of each compound,and explored the structure-activity relationship between the activity of curcuminoids and the structure,position,and number of substituents,and provides basis for optimizing the scientific structure of curcumin.In vitro,free radicals?DPPH·,O₂^-·,·OH,ROO·,and ABTS·⁺?scavenging experiments and FRAP experiment were performed,the results showed that as the concentration of curcuminoids increasing,the free radical scavenging activity and reducing ability were dose-dependency.In the same scavenging model,the antioxidant activity of curcuminoids was different.Based on the structures of curcuminoids,the phenolic hydroxyl group,the enol hydroxyl group,the heptadiene-3,5 diketone long chain structure and the methoxy group play different roles in the antioxidant activity of curcuminoids.By investigated the inhibitory effect of curcuminoids on CCl₄-induced lipid peroxidation of liver homogenate,the results showed that with increasing concentration of curcuminoids,the system T-AOC levels increased,MDA content decreased,and activity of antioxidant enzymes?SOD,CAT,GSH-Px?increased.The results showed that CUR,DMC,BDMC,BIMC,and CURC had protective effects on CCl₄-induced liver injury.Quantitative theoretical calculations were conducted to further explore the anti-oxidation mechanism of curcuminoids and to evaluate the BDE,IP,and?_ELUMO-HOMO.The results showed that the principle of compounds scavenging DPPH·was proton transfer reaction,the mechanism of eliminating ABTS·⁺,ROO·,·OH,and O₂^-·was the reaction of protons with electron transfer,and curcuminoids have antioxidant activity.The above results showed that curcuminoids CUR,DMC,BDMC,BIMC and CURC have good antioxidant activity.This study can provide the scientific basis on antioxidant of curcuminoids in in-depth development and utilization.