Pacific Dulse Protein: A Promising Source of Bioactive Peptides

Abstract

Abstract Objectives Pacific dulse (Devaleraea mollis) is a protein-rich seaweed in the Pacific Northwest and increasingly being cultivated as food resource. Our previous work showed that dietary supplementation of dulse exerted beneficial metabolic effects to the high-fat fed mouse model. This study aims to evaluate the potential of the seaweed protein from dulse as a precursor for bioactive peptide (BAP) generation. Methods The potential of Pacific dulse protein as BAP precursor was assessed using in vitro and in silico approaches. Hydrolysates were prepared from the hydrated freeze-dried protein isolates which were digested using commercial proteases. These were used for the in vitro screening for antioxidant and anti-inflammatory activities as well as the inhibition of Angiotensin-converting enzyme 1 (ACE-1), Renin, and Dipeptidyl peptidase IV (DPPIV). Peptides in the hydrolysates that exhibit the highest activities were identified using de novo sequencing. Identified peptides were shortlisted based on their potential to be bioactive using Peptide Ranker and specific bioactivity scores were obtained using in silico platforms such as iDPPIV-SCM and PreAIP. To determine whether the consumption of the seaweed protein may help give rise to some bioactive peptides, annotated protein sequences of the seaweed material were obtained from UniProtKB and were subjected to in silico digestion using pepsin, chymotrypsin, and trypsin through BIOPEP. Bioactivity indices of the generated peptide fragments were recorded as predictive values. Results In silico digestion showed that dulse proteins can give rise to ACE-1, DPP-IV, and renin inhibitors, as well as antioxidant peptides. Hydrolysates exerted inhibitory effects on human ACE-1, DPPIV, and renin in vitro. ABTS radical scavenging assay and cellular antioxidant activity assay in human hepatocytes indicated the strong antioxidant potential of dulse BAP. Peptides identified through de novo sequencing had high predictive scores for DDPIV inhibition and anti-inflammatory potential. Conclusions Pacific dulse proteins is a promising precursor for the generation of BAPs that may exert beneficial health activities and support metabolic health improvement. Funding Sources Oregon State University Agricultural Research Foundation.