Antioxidative and ACE- inhibitory activity of enzymatic hydrolysates of jellyfish Rhopilema esculentum Kishinouye gonad

To obtain antioxidant peptides and antihypertensive peptides from Jellyfish Rhopilema esculentum Kishinouye gonad protein hydrolysate( JGPH),Trypsin,Papain,Alcalase and Neutrase were employed for enzymatic hydrolysis. Then degree of hydrolysis,antioxidant activities and antihypertensive activities of their hydrolysates were investigated using both 1,1- diphenyl-2- picrylhydrazyl( DPPH) radical scavenging assay and angiotensin- I- converting enzyme( ACE) inhibition assay. JGPH was ultrafiltrated using ultrafiltration membranes( molecular weight cut-offs of 1000 and 3000 u) to obtain three components JGPH-P1-3 which molecular weight distributions were > 3000 u,1000 ~3000 u and < 1000 u,then antioxidant activities and antihypertensive activities of three components were investigated. The results revealed that degree of hydrolysis,DPPH radical scavenging activity and ACE- inhibitory activity of JGPH prepared by Neutrase were the highest,and Neutrase was selected as the tool enzyme.JGPH- P3 had the highest DPPH radical scavenging activity and ACE- inhibitory activity( IC50=1.06 mg / m L). And its DPPH radical scavenging activity( IC50= 0.38 mg / m L),hydroxyl radical scavenging activity( IC50= 0.63 mg / m L) and superoxide anion radical scavenging activity( IC50= 0.59 mg / m L) were investigated by using electron spin resonance measurement( ESR).Thus,molecular weight less than 1000 u of of JGPH prepared by Neutrase exhibited high antioxidant activities and antihypertensive activities.