An angiotensin-converting enzyme inhibitory peptide LVLPGE exerts an antihypertensive effect and improves endothelial function via eNOS/NO/cGMP pathway

LVLPGE is an angiotensin-converting enzyme (ACE) inhibitory peptide extracted from broccoli protein hydrolysates. The antihypertensive mechanism of LVLPGE was explored in the present study. The results indicated that the IC 50 value of LVLPGE was 19.49 μM, and its binding to ACE occurred via a static fluorescence quenching involving the secondary structure changes of ACE. In addition, LVLPGE competitively bound to the active site of ACE through hydrogen bonding. Furthermore, LVLPGE markedly enhanced the levels of the vasodilator nitric oxide (NO) in the Ang I-induced HUVECs model, suppressed the expression of vasoconstrictor endothelin-1 (ET-1), and increased the phosphorylation of eNOS. Moreover, LVLPGE was found to enhance the production of cyclic guanosine monophosphate (cGMP), which leading to a subsequent decrease in intracellular calcium concentration, ultimately facilitating the relaxation of vascular smooth muscles and lowering the blood pressure. These results demonstrated that LVLPGE achieves the antihypertensive effects by inhibiting ACE activity and activating the eNOS/NO/cGMP signaling pathway. This study provides new insights into the antihypertensive mechanism of LVLPGE and contributes to the high-value utilization of broccoli resources.