Study On The Extraction And Purification Process Of Angiotensin I-Convert Enzyme Inhibitor From Agrocybe Aegirit

Hypertension is one kind of the clinical syndrome taking that arterial systolic pressure or diastolic pressure rises as characteristic,it frequently accompanies heart,blood vessels, kidney and brain diseases.A number of peptides which can depress blood pressure have been isolated and characterized from foods.The peptide which also named ACE-inhibitory peptide (ACEI)by inhibiting the activity of Angiotensin-converting enzyme(ACE)to depress the blood pressure.Taking Agrocybe aegirit as the raw materals,the effect of solvent on extraction of ACEI and its inhibition for ACE was tasted.The water extracts showed the extraction rate(D)and the inhibitory activity(IP)at 85.78%and 48.43%;the ethanol(50%)extracts showed the D and IP at 41.48%and 49.16%.Therefore,distill water was selected as extraction solvent. Meanwhile,the optimal extraction conditions of ACEI from Agrocybe aegirit was investtigated. The result showed that the optimal extraction conditions as following:extraction time was 9 hour,extraction temperature 30℃,and then the D and IP were 88.3%and 49.3%.Activated carbon was adopted in decolour water extracts solution by single factor experiment. The factors including quantity of activated carbon,temperat- ure,pH,and adsorption time were investigated in terms of decolouring efficiency(D_c)and bioactivity loss(L_p).The results showed that optimum decoloration effect was obtained from the following conditions: quantity of activated carbon 0.5%,temperature 40℃,pH value 3.5,and adsorption time 40 minutes.Then decolouring efficiency and bioactivity loss were 78.86%and 15.68%,and inhibitory activity(IP)was 41.57%.Water extracts solution which was decoloured with the activated carbon was separated with ultrafiltrate membrane which molecular weight is 10 kDa.Further purification of the active fraction was carried out by gel-filtration with Sephadex Gel-25 and Sephadex Gel-15. The filter solution was isolated three peaks with the Gel-15 when eluted with water at a flow rate of 1.0 mL·min^-1and initial volume at 3 mL,the peptide total yield(R_p)was 91.1%.The third peak has the strongest inhibitory to ACE,the inhibitory activity(IP)was 41.57%,and the peptide yield(R_p)was 25.6%.The third peak's sample was purified by RP-HPLC,it can be separated into four components.The highest active component which namedâ…¢-d(1)was identified by RP-HPLC, its purity can reach 95%,and IC₅₀was 0.0109 mg·mL^-1.