The Research On Bioactive Peptides Derived From Marine Microalgae

Microalgae is an important marine microorganisms.It is focus on activity of carbonhyrate,terpenoids and polyphenols that much research work have developed about marine microalgae at present,but so less focus on the study of protein and polypeptide.This research was based on activities of anti-inflammatory and antibacterial to hydrolysates of Schizochytrium algal meal by enzyme,and explored the preliminarily mechanism of anti-inflammatory.Firstly,the conditions of optimum enzymatic hydrolysis were established about Schizohytrium algal meal.The content of protein in the hydrolysate was analyzed by LC-MS mass spectrometry and UV spectrophotometry.The results show that the recovery could obtain the highest up to 47.95%when Schizohytrium algal meal were hydrolyzed by 3%of pepsin and 3%of trypsin together within 6 h.The enzyme extracts of hydrolysates were analyzed by LC-MS mass spectrometry and UV spectrop ho to metric method to determine the products of extracts to be peptide mixture with molecular weight no more than 3000 Da.Secondly,anti-inflammatory activity of the peptide mixture was determined on mice and its mechanism was explored.The mice model on inflammatory was established using xylene.The levels of mice inflammatory swelling of auricle induced by xylene were tested by enzyme extracts with different doses about high dose group(1000 mg/kg),medium dose group(500 mg/kg)and low dose(250 mg/kg).The results show that the mice auricle swelling rate was the lowat the enzymatic hydrolysis peptides concentration of 500 mg/kg mice auricle swelling rate is the lowest only to be 49.85%at the concentration of the peptide mixture of 500 mg/kg.At the same situation,the superoxide dismutase(SOD)activity,content of inflammatory tissue exudate malondialdehhyde(MDA),content of protein and prostaglandin E2(PGE2)were evalucated separately by the method of mouse right foot toe injection of 1%carrageenan,using peptide mixture with concentration of high,medium and low dose groups.The results show that it was the medium dose group(500 mg/kg)to have the highest activity of the SOD to be up to 109.79-U/mg,but the protein concentration was the lowest,only to be 0.598 g/L,The inflammatory tissueexudate of MDA and PGE2 in the medium dose were the lowest,to be 1.142 nmol/mgprot and at 278 nm absorbance of PGE2 the lowest,only to be 0.141.Therefore,peptide mixture have an effect on therapeutic inflammatory.Finally,the activities of antibacterial were determined on the basis of Escherichia coli,Staphylococcus aureus and Salmonella using the peptide mixture under the concentration gradients(120 mg/ml,100 mg/ml,80 mg/ml,60 mg/ml 40 mg/ml,20 mg/ml,0 mg/ml).The results showed that the peptide mixture had a certain extent antibacterial effect against E.coli,Staphylococcus aureus,and Salmonella.Its antibacterial effect against Escherichia coli and Staphylococcus aureus was almost 100%with the concentration of peptide mixture of 100 mg/ml.However,the effect on Salmonella was weak to be 58%under the concentration of peptide mixture at 100 mg/ml for 12 h.Furthermore,comparison with the test group which the meal was not hydrolyzed by enzyme,it was peptide mixture to inhibit activity of bacterial.In summary,there were bioactive peptides in the peptide mixture to have effect not only on anti-inflammation and inhibit the growth of microorganisms,but also on certain treatment of inflammation.It was verified that the main active substances to be peptides with the molecular weight no more than 3000 Da.