title: Antihypertensive and free radical scavenging properties of enzymatic rapeseed protein hydrolysates.
abstract: In this study, rapeseed protein isolate (RPI) was digested with various proteases to produce rapeseed protein hydrolysates (RPHs), which were then separated into different peptide fractions (<1, 1-3, 3-5, and 5-10kDa) by membrane ultrafiltration. Membrane fractionation showed that peptides with sizes <3 kDa had significantly (p<0.05) reduced surface hydrophobicity when compared to the RPHs and peptide fractions with sizes >3 kDa. In contrast, the <3 kDa peptides showed significantly (p<0.05) higher oxygen radical scavenging ability when compared to the >3 kDa peptides and RPHs. In vitro inhibition of angiotensin I-converting enzyme (ACE) was significantly (p<0.05) higher for the Thermolysin, Proteinase K and Alcalase RPHs when compared to the pepsin+pancreatin (PP) and Flavourzyme RPHs. The Alcalase RPH had significantly (p<0.05) higher renin inhibition among the RPHs, while with the exception of Thermolysin, the 5-10 kDa peptide fraction had the least renin-inhibitory ability when compared to the <5 kDa peptide fractions. Oral administration (100mg/kg body weight) of the RPHs and RPI to spontaneously hypertensive rats (SHR) showed the Alcalase RPH to be the most effective in blood pressure (BP) reduction (∼24 mm Hg) while Proteinase K RPH was the least effective (∼5 mm Hg) after 8h. However, the PP RPH had the most prolonged effect with BP reduction of ∼20 mm Hg after 24h of oral administration. We conclude that the strong BP-lowering ability of Alcalase and PP RPHs could be due to high resistance of the peptides to structural degradation coupled with high absorption rate within the gastrointestinal tract.
authors.affiliation: College of Food Science, Jiangnan University, Wuxi 214122, People's Republic of China. ronghe.nufe@hotmail.com
authors.forename: Rong
authors.initials: R
authors.lastname: He
authors.forename: Adeola
authors.initials: A
authors.lastname: Alashi
authors.forename: Sunday A
authors.initials: SA
authors.lastname: Malomo
authors.forename: Abraham T
authors.initials: AT
authors.lastname: Girgih
authors.forename: Dongfang
authors.initials: D
authors.lastname: Chao
authors.forename: Xingrong
authors.initials: X
authors.lastname: Ju
authors.forename: Rotimi E
authors.initials: RE
authors.lastname: Aluko
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage* / Q000737:chemistry; D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage* / Q000737:chemistry; D001794:Blood Pressure / Q000187:drug effects; D029741:Brassica rapa / Q000737:chemistry*; D005260:Female; D016166:Free Radical Scavengers / Q000008:administration & dosage* / Q000737:chemistry; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D010447:Peptide Hydrolases / Q000737:chemistry; D010940:Plant Proteins / Q000008:administration & dosage / Q000737:chemistry; D011492:Protein Hydrolysates / Q000008:administration & dosage* / Q000737:chemistry; D051381:Rats; D011918:Rats, Inbred SHR
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D016166:Free Radical Scavengers; D010940:Plant Proteins; D011492:Protein Hydrolysates; D010447:Peptide Hydrolases