Antihypertensive effect of protein hydrolysate from azufrado beans in spontaneously hypertensive rats

The objective of this study was to evaluate the antihypertensive potential of common bean protein hydrolysate. Protein concentrates were obtained, followed by Alcalase enzymatic hydrolysis, and then ultrafiltrated (3,000 molecular weight cutoff); the lyophilized product was named BP3. The angiotensin converting enzyme (ACE) inhibitory activity was determined as IC50 (3.68 ± 0.07 μg/mL). The antihypertensive effect was evaluated in spontaneously hypertensive rats (SHR) by two assays; Captopril ACE inhibitor was used as a reference compound and water as a control. A short-term assay showed a maximum decrease in mean arterial pressure of -41 ± 5 mmHg in SHR, 3 h after oral administration of 500 mg of BP3/kg of body weight (bw). In a long-term assay, a significant decrease in systolic blood pressure of -24 ± 5 mmHg was observed in SHR, after 45 days of oral administration of 500 mg of BP3/kg of bw/12 h. In both assays, BP3 treatment showed antihypertensive effect over SHR, similar to Captopril treatment. The sequences of the most abundant peptides present in BP3, determined by mass spectrometry, were identified as KFPWVK, GADFRKK, and PQSPCKRVNRHS. These peptides are reported for the first time in Azufrado Higuera common beans, and they are most likely responsible for the antihypertensive effect of BP3.