Search

Context: Multifunctional food protein-derived peptides attract a great deal of research interest due to their health-promoting benefits. Particularly, peptides that have both antihypertensive and antioxidant properties are desired, since both effects can be synergistic in prevention of cardiovascular diseases., Aim: The aim of this study was to investigate the angiotensin-I-converting enzyme (ACE) inhibitory and 2,2 ' -diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities of two species of the Nigerian periwinkles: Pachymelania aurita and Tympanotonus fuscatus ., Methods: The ACE inhibitory and 2,2 ' -diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities of simulated gastrointestinal digestion (SGID) hydrolysates and ultrafiltered (UF) fractions of T. fuscatus var. radula and P. aurita were determined. Human SGID of the protein extracts of T. fuscatus and P. aurita was carried out using pepsin, trypsin, and chymotrypsin, and the hydrolysates were fractionated into two by centrifugal ultrafiltration. The ACE inhibitory and DPPH radical scavenging activities of the crude hydrolysates and UF fractions were tested. The UF permeates were observed to have relatively higher activities and was subjected to gel filtration chromatography on Sephadex G-50. The chromatographic fractions showed absorbance at 215, 225, and 280 nm and were assayed for DPPH radical scavenging activity., Results: The inhibitory effect of the fractions on ACE activity was reported as the minimum concentration of extract that caused 50% of the inhibition (IC 50 ), where the IC 50 values of P. aurita UF permeate and P. aurita UF retentate were 65.2 ± 6.4 and 301.9 ± 59.1 μg/ml, respectively, and that of T. fuscatus UF permeate (TFUFP) and T. fuscatus UF retentate were 54.93 ± 2.83 and 291.7 ± 8.6 μg/ml, respectively., Conclusion: This study suggests the potential health benefits of consuming T. fuscatus var. radula and P. aurita in health maintenance., Competing Interests: There are no conflicts of interest., (Copyright: © 2021 International Journal of Applied and Basic Medical Research.)

The multifunctional nature of antioxidant peptides makes them more attractive candidates as dietary ingredients in health maintenance. Therefore, food protein-derived antioxidant peptides are continuously investigated. This study investigated the in vitro antioxidant properties of hydrolysate and ultrafiltered peptide fractions of Pachymelania aurita and Tympanatonus fuscatus var radula-two commonly consumed marine molluscs known as periwinkles in southern Nigeria. Simulated gastrointestinal digestion (SGID) of soluble proteins of T. fuscatus and P. aurita was carried out using pepsin, trypsin and chymotrypsin, and the SGID hydrolysates were fractionated using a 3 kDa membrane filter. The hydrolysates and their fractions were investigated for anti-lipid peroxidation, hydroxyl radical scavenging activity (HRSA), ferric reducing antioxidant property (FRAP) and metal chelation activity, and they demonstrated clear antioxidant properties in all the assay models used. Low molecular weight fractions of the hydrolysates demonstrated more potent antioxidant activity than higher molecular weight fractions. This is profound in the metal chelation assay, where low molecular weight peptide fractions, T ≤ 3 kDa and P ≤ 3 kDa (IC 50 values of 8.10 ± 0.011 and 5.56 ± 0.50 µg/ml respectively) had activity that is similar to that of EDTA (11.84 ± 0.89 µg/ml). Similar activity effects were observed in other assays where there was about 3-fold higher activity in low molecular weight fractions. These results demonstrate the presence of antioxidant peptide(s) in the protein hydrolysates of the periwinkles., Competing Interests: None., (IJBMB Copyright © 2021.)