Antihypertensive and antioxidant effects of food‐derived bioactive peptides in spontaneously hypertensive rats

Hypertension significantly impacts the survival and quality of life of animals, often leading to chronic kidney failure. Current clinical drugs used to manage hypertension carry the risk of causing adverse reactions. In contrast, certain natural peptides have demonstrated the ability to safely reduce blood pressure by inhibiting the production of angiotensin. We administered four biologically active peptide solutions to spontaneously hypertensive rats: derived from corn, wheat, egg white, and soybean. The efficacy of these peptides in reducing blood pressure was assessed through regular measurements of systolic pressure. Additionally, we analyzed levels of angiotensin-converting enzyme and angiotensin 2 using immunohistochemistry and ELISA in vivo. The indicators of oxidative stress and inflammation in hypertensive rats were evaluated using qRT-PCR and ELISA, respectively. Both wheat (from 182.5 ± 12.26 mmHg at day 0 to 168.86 ± 5.86 mmHg at day 20, <i>p</i> = .0435) and soybean (from 189 ± 2.19 mmHg at day 0 to 178.25 ± 5.14 mmHg at day 20, <i>p</i> = .0017) notably lowered systolic blood pressure compared to their starting systolic blood pressures in spontaneously hypertensive rats. Both wheat and soybean peptides significantly reduced plasma ANG II levels, akin to captopril's effect. Wheat peptides additionally exhibited antioxidant properties. Only the corn peptide showed a significant increase in transcript levels of the proinflammatory factors IL-6 and TNF-α. At the protein level, all four kinds of peptides significantly elevated IL-6 levels while inhibiting TNF-α secretion. This study demonstrates that wheat peptides and soybean peptides administered as dietary supplements exhibit significant hypotensive and antioxidant effects.