Protein Hydrolysates from Brewing By-Products as Natural Alternatives to ACE-Inhibitory Drugs for Hypertension Management

The treatment of hypertension is of major importance to reduce the risk of cardiovascular disease, the leading cause of death worldwide. Angiotensin-converting enzyme (ACE) inhibitors are anti-hypertensive drugs associated with several side effects. Natural products, namely bioactive peptides from brewing by-products, brewers' spent grain (BSG), and yeast (BSY), are promising alternatives since they can inhibit ACE in vitro. However, the oral intake of these peptides may modify their expected inhibitory effect owing to possible changes in active peptides' bioavailability, which have not been assessed so far. The goal of this study was to simulate oral administration to evaluate BSG/BSY peptides' effectiveness by submitting protein hydrolysates sequentially to simulated gastrointestinal digestion, intestinal absorption (Caco-2 cells), and liver metabolism (HepG2 cells). MTT assay was used to assess BSG/BSY protein hydrolysates safeness. The ACE-inhibitory potential of initial and final protein hydrolysates (BSY, BSG, and a new product, MIX) were tested using a fluorometric assay and compared with captopril (1 µM, an ACE-inhibitory drug). Simulation of oral administration greatly increased BSY and MIX protein hydrolysates' ACE-inhibitory capacity, though final MIX and BSG revealed greater ACE-inhibitory potential than captopril. Notwithstanding, all final protein hydrolysates presented ACE-inhibitory capacity, thus being promising compounds to manage hypertension.