Antihypertensive Effect of Angiotensin-Converting Enzyme Inhibitory Peptide Obtained from Hen Ovotransferrin

Isolation and characterization of peptides with antihypertensive activity in foodstuffs

Hypertension is one of the main causes of cardiovascular diseases. Synthetic drugs inhibiting ACE activity present high effectiveness in the treatment of hypertension but cause undesirable side effects. Unlike these synthetic drugs, antihypertensive peptides do not show any adverse effect. These peptides are naturally present in some foods and since hypertension is closely related to modern diet habits, the interest for this kind of foods is increasing. Different methods for the purification, isolation, and characterization of antihypertensive peptides in foods have been developed. Nevertheless, there is no revision work summarizing and comparing these strategies. In this review, in vivo and in vitro pathways to obtain antihypertensive peptides have been summarized. The ACE mechanism and the methodologies developed to assay the ACE inhibitory activity have also been described. Moreover, a comprehensive overview on the isolation, purification, and identification techniques focusing on the discovery of new antihypertensive peptides with high activity has been included. Finally, it is worthy to highlight that the quantitation of antihypertensive peptides in foods is a new trend since genotype and processing conditions could affect their presence. Analytical methodologies using mass spectrometry constitute an interesting option for this purpose.

Naturally occurring angiotensin I-converting enzyme inhibitory peptide from a fertilized egg and its inhibitory mechanism

This study was performed to investigate the angiotensin I-converting enzyme (ACE) inhibitory activity of peptides derived from fertilized eggs and elucidate the inhibition mechanism of these peptides. During incubation, ACE inhibitory activity of the peptides remained stable before day 12 and then increased markedly on day 15. Two ACE inhibitory peptides, VGVIKAVDKKAGGAGKVT and HLFGPPGKKDPV, were purified from peptides on day 15 by consecutive chromatography. Because HLFGPPGKKDPV possessed a higher ACE inhibitory activity (IC50 = 125 μM), an antihypertensive effect of this peptide was further evaluated in vivo. The result showed that this peptide had an antihypertensive effect in spontaneously hypertensive rats (SHRs) at a dosage of 10 mg/kg. Furthermore, Lineweaver-Burk plots suggested that HLFGPPGKKDPV played as a non-competitive inhibitor against ACE, as supported by docking simulation. These data indicated that a fertilized egg has potential as antihypertensive components in functional foods and nutraceuticals.