Study On Protective Effect Of Cod Skin Collagen Peptides Against Skin Photoaging And Its Action Mechanism

With the improvement of living standards,people's pursuit of beauty is getting higher and higher,and the problem of skin photoaging is also getting more and more attention.Collagen peptides are widely recognized as having the effect of improving skin photoaging,but currently mainly focused on the evaluation of collagen proteolytic activity and the isolation and identification of collagen peptides,but there are few studies on the efficient screening and targeted preparation of collagen peptide.Therefore,this subject uses deep-sea cod skin as raw material,and uses light-damaged fibroblasts as a model to investigate the difference in anti-skin photoaging activity of collagen peptides prepared by enzymatic hydrolysis under different conditions,combined with analysis of peptidomics and peptide ranker.The software quickly screened collagen peptides with potential anti-photoaging activity,on the basis of which the mechanism of protecting fibroblasts from light damage was explored,and finally the enzymatic hydrolysis of cod skin collagen peptides with high content of active peptides was determined.Craftsmanship.The main results and conclusions of this topic are as follows:?1?Using acidic,neutral and alkaline proteases to prepare different hydrolysis degrees of cod skin hydrolysates,comparative analysis of their protein recovery rate,degree of hydrolysis and repair activity of photodamaged fibroblasts,the results found that alkaline protease The enzymolysis of cod skin hydrolysate under the enzymatic hydrolysis for 5 h has the best hydrolysis efficiency,and the recovery rate and degree of hydrolysis reach 85.6%and20.55%;the collagenase inhibitory activity and the cell survival rate of photodamaged fibroblasts are also the highest,66.99%,73.56%,and the enzymolysis efficiency and anti-photoaging activity of the enzymolysis solution prepared by the three proteases increased with the increase of enzymatic hydrolysis time.Comprehensive analysis of their molecular weight distribution,amino acid composition,and peptide composition revealed that there was a significant difference in peptide composition and content between the cod skin alkaline protease hydrolysate and the other two enzymes,and further combined with mass spectrometry and PCA analysis methods to screen Seven collagen peptide sequences with potential anti-photoaging activity were generated,which were GPA,GPL,GX?X represents hydroxyproline?,GL,GPPGPTGA,AGPAGPR and GY.?2?The photodamaged fibroblast model was used to evaluate the anti-skin photoaging activity of 6 collagen peptides including GPA,GPL,GX,GL,GPPGPTGA and GY,and proceeded from oxidative stress,ECM loss,and apoptosis The protective mechanism of these collagen peptides on photodamaged fibroblast cells was studied.It was found that these 6peptides can significantly improve the survival rate of photodamaged fibroblasts?p<0.5?,of which GPPGPTGA activity is the best,followed by GX,then GPA,then GY,then GPL,and finally GL.In addition,these six collagen peptides can inhibit ROS production,increase SOD activity,inhibit collagenase production,reduce collagen content,inhibit Ca²⁺ion influx and improve mitochondrial membrane potential?MMP?loss to varying degrees.Among them,GPPGPTGA has the best effect in these six aspects,which may be the reason for its best anti-photoaging activity.?3?Using protein hydrolysis degree and recovery rate as indicators,combined with the relative content of target peptide and the repair activity of photodamaged fibroblasts,the directional enzymolysis process of cod skin was optimized.The results showed that among the six selected proteases,cod skin collagen peptides prepared by pancreatin had the highest protein recovery and hydrolysis degree,the highest content of small molecule peptides,and the highest relative content of anti-photoaging target peptides GPPGPTGA and GX;The optimal process condition is that the amount of enzyme added is 0.4%?w/w relative to fish skin?,the p H is 9,and the enzyme is hydrolyzed for 5 h.The protein recovery and hydrolysis degree of the cod skin collagen peptide prepared under these conditions were 87.89%and 27.11%,respectively;relative to the commercial collagen peptide,the relative content of GPPGPTGA was 478.23%,and the relative content of GX was 1167.84%,The relative content of GPA is527.47%;the peptide component of less than 3 k Da reaches 98.78%,and the anti-photoaging effect is obvious from the results of cell morphology observation experiment and cell survival rate experiment.