Research On The Mechanism Of Natural Antioxidants In Inhibiting Nitrogen/Oxygen Free Radical Damage

Free radicals are involved in regulating physiological metabolism,but when human in sub-health state,the abnormal accumulation of free radicals can cause diseases.The peroxynitrite(ONOO~-)has multiple pathways of strong damage,which can lead to a variety of diseases such as rheumatoid arthritis,sepsis,Parkinson's and cancer.There is lack of specific clearance enzyme of peroxynitrite in human body,so it is necessary to develop antioxidants for peroxynitrite.Aurantio obtusin,6-gingerol,allicin,betaine and piperine are common natural antioxidants,the study of the interaction between five natural antioxidants and free radicals and human serum albumin(HSA)is beneficial to the understanding of the transport,metabolism,distribution and antioxidant activity of five kinds natural antioxidants in human body.In this study,the mechanism and medicinal value of natural antioxidants are elucidated.In this study,the inhibitory rates of dimer-tyrosine by 6-gingerol,aurantio obtusin,piperine and allicin were determined by fluorescence spectroscopy.The ability of these natural antioxidants to inhibit 3-nitrotyrosine was determined by using HPLC-PAD to eliminate the interference.The inhibitory rates of superoxide anion was determined by pyrogallol autoxidation method.The binding process of aurantio obtusin,6-gingerol,allicin,piperine,betaine,ONOO~-and HSA were compared by fluorescence spectrometry and synchronous fluorescence spectroscopy,and the inhibition ability of the natural antioxidants on the direct damage of HSA induced by ONOO~-was compared.Among the aurantio obtusin,piperine,allicin,6-gingerol and vitamin C(V_C),the inhibitory effect of aurantio obtusin on superoxide anion was the most obvious,6-ginger and piperine had the most obvious inhibitory effect on oxidative and nitrification injury induced by peroxynitrite.There was no obvious combination of betaine and HSA,The other four natural antioxidants can bind to HSA through hydrophobic interaction and have 1 binding site near tryptophan.The binding process is spontaneous static quenching,binding ability:piperine>aurantio obtusin>6-gingiphenol>allicin.Four natural antioxidants did not affect the conformation of HSA significantly.ONOO~-and HSA can be combined by hydrogen bonding or van Edward force,the binding process is spontaneous static quenching,with 1 binding sites near tryptophan disability.And ONOO~-has caused damage to HSA conformation.Aurantio obtusin,6-gingerol,allicin,piperine and betaine have good ability to inhibit the direct damage of human serum albumin induced by peroxynitrite at low concentrations,and inhibition rates from high to low are allicin>piperine>6-gingiphenol>aurantio obtusin>V_C>betaine.