Study On Enhancing Antioxidant Activity Of Bioactive Peptides From Colla Corii Asini(ejiao)

Colla corii asini(E'jiao)curative function has been widely recognized and has been hailed as China's intangible cultural heritage.Many studies show the efficacy of many products is closely related to their antioxidant activity.Thus,it is very meaningful to improve the antioxidant activity of E'jiao peptides.Different methods for improving the antioxidant activity of E'jiao peptides were systematically studied.And we will provide the theoretical basis and experimental data for the development and utilization of E'jiao peptides.The main research content is as follows:Firstly,the effects the antioxidant activity of different proteases on the hydrolysis of E'jiao were investigated,and the influence of hydrolysis products on DPPH,ABTS,and OH radical scavenging capacity was revealed.The results showed that the alkaline protease hydrolyzate had the strongest antioxidant activity.The optimal preparation conditions of E'jiao peptides were obtained by response surface experimental design:temperature 40?,pH 8.2 and enzyme dosage 5199 U/g.Secondly,the effect of the ultrafiltration technique on the antioxidant activity of E'jiao peptides was investigated.The results showed that compared with the pre-separation product,the antioxidant activity of SACCH-?(<3 kDa)component was significantly improved.Through amino acid composition analysis and circular dichroism test,it was found that the content of hydrophobic amino acids and the secondary structure of amino acids in SACCH-II are closely related to its higher antioxidant activity.Thirdly,the compound of Ginkgo biloba extract(EGb)and E'jiao peptides was designed and prepared to effectively improve the antioxidant properties of E'jiao peptides.The effects of the mass ratio of EGb and ACCH on its antioxidant activity were studied.The results showed that there is antioxidant synergy between ACCH and EGb.Furthermore,the inhibition of breast cancer cells MCF-7 and MDA-MB-231 proliferation increased when these cell lines were treated with a combination of ACCH and EGb for 72 h,with IC50 of 4.32±0.12 mg/ml and 0.39±0.01 mg/mL,respectively.In addition,the mixtures were cell selective and destroyed only tumor cells and not normal cells.This has led to the development of new methods for the application of E'jiao peptides.