Purification and Characterization of Novel Antihypertensive and Antioxidative Peptides From Whey Protein Fermentate: In Vitro, In Silico, and Molecular Interactions Studies.

OBJECTIVE: The goal of this research was to purify and characterize the novel angiotensin-converting enzyme (ACE)-inhibitory and antioxidant peptides from fermented whey protein concentrate produced by Lactobacillus paracasei and Saccharomyces cerevisiae in a co-fermentation system. METHOD: Whey protein fermented with lactic acid bacteria and yeast culture was analyzed for antioxidative, ACE inhibition, as well as anti-inflammatory activity followed by SDS-PAGE, isoelectric focusing, and 2-dimensional (2D) analysis. Anti-inflammatory activity of whey protein fermentate was also studied on the RAW 264.7 cell line. The bioactive peptides were separated from the whey protein fermentate using reverse-phase high-performance liquid chromatography (RP-HPLC) and reverse-phase liquid chromatography mass spectrometry (RPLC/MS), and thus identification and characterization of purified bioactive peptide was performed. RESULTS: Whey protein fermentate samples' bioactivity was analyzed at specific time intervals at 12, 24, 36, and 48 hours at 37 °C for M11 and at 25 °C for WBS2A. The development settings (incubation time [12, 24, 36, and 48 hours) and inoculation rates [1.5%, 2.0%, and 2.5%]) were optimized for peptide synthesis via the o-phthaldialdehyde (OPA) method (proteolytic activity). Maximum proteolytic activity was observed at 37 °C for M11 (6.50 mg/mL) and at 25 °C for WBS2A (8.59 mg/mL) for 48 hours of incubation. Protein profiling was carried out using SDS-PAGE and 2D gel electrophoresis, in which Sodium dodecyl-sulfate (SDS) exhibited protein bands in the 10- to 55-kDa range, while 2D showed protein bands varying from 10 to 70 kDa. Every spot from 2D was digested by trypsin and identified by RPLC/MS. Protein fractionations (3- and 10-kDa permeates) were carried out employing RP-HPLC. Whey protein fermentate has anti-inflammatory action in RAW 264.7 macrophages that have been exposed to lipopolysaccharide. A molecular docking system was also used to investigate the interactions of peptides (AFLDSRTR, ILGAFIQIITFR) with human myeloperoxidase enzyme. CONCLUSIONS: The antihypertensive and antioxidative peptides discovered from whey protein fermentate may be helpful in the design of pharmacologically active healthy ingredients in the upcoming years.

Current Trends and Applications of Food-derived Antihypertensive Peptides for the Management of Cardiovascular Disease.

Food-derived antihypertensive peptides are considered a natural supplement for controlling hypertension. Food protein serves as a macronutrient and acts as a raw material for the biosynthesis of physiologically active peptides. Food sources, like milk and milk products, animal proteins such as meat, chicken, fish, eggs, and plant-derived proteins from food products like soy, rice, wheat, mushroom, and pumpkins contain higher quantities of antihypertensive peptides. The food-derived antihypertensive peptides can suppress the action of renin and the angiotensinconverting enzyme (ACE), which are mainly involved in the regulation of blood pressure by RAS. ACE inhibitory peptides enhance endothelial nitric oxide's biosynthesis, which increases nitric oxide production in vascular walls and encourages vasodilation. The peptides also inhibit the interaction between angiotensin II and its receptor, which helps reduce hypertension. This review explores the novel sources and applications of food-derived peptides for the management of hypertension.