Anti-Hypertensive Activity of Novel Peptides Identified from Olive Flounder (Paralichthys olivaceus) Surimi

Abstract

There is a growing interest in the health benefits of functional foods. A benefit that has been long sought is the control of hypertension through dietary approaches. Hypertension has been implicated as a risk factor for cardiovascular disease and is therefore of clinical significance. Here, we aim to demonstrate the antihypertensive activity of novel peptides derived from surimi, a functional food ingredient made from refined fish myofibrillar proteins. Three peptides, Ile-Val-Asp-Arg (IVDR), Trp-Tyr-Lys (WYK), and Val-Ala-Ser-Val-Ile (VASVI), were isolated from surimi made from the olive flounder (Paralichthys olivaceus). Our results show that IVDR, WYK, and VASVI exhibited high Angiotensin I-converting Enzyme (ACE) inhibition activity. These peptides are also shown to increase phosphorylation of protein kinase B (Akt) and endothelial nitric oxide synthase (eNOS), and significantly promote nitric oxide (NO) production in human umbilical vein endothelial cells. Oral administration of the peptides decreased blood pressure in spontaneously hypertensive rats (SHRs), thereby confirming that the peptides derived from surimi perform antihypertensive activity via the Akt/eNOS pathway. These results indicate that surimi made from P. olivaceus contains novel antihypertensive peptides that could be used to enhance the health benefits of food ingredients.

Keywords: Paralichthys olivaceus; antihypertensive; peptide; surimi.

Figure 1

Induction of NO production by the peptides. The HUVECs were treated with various concentrations (µg/mL) of the peptides for 3 h. The values are means ± SD of triplicate experiments. * p < 0.05, ** p < 0.01, *** p < 0.001 as compared to control.

Figure 2

Akt/eNOS phosphorylation level was determined via Western blot analysis in endothelial cells treated with the peptides. The values are means ± SD of triplicate experiments. ^### p < 0.001 (positive control compared to non-treated group), ** p < 0.01, *** p < 0.001 (sample group compared to non-treated group).

Figure 3

Change in systolic blood pressure (SBP) after oral administration of the peptides in SHRs. (♦) Control (saline); (■) positive control (peptide derived from Sardino melanostictus); (▲) IVDR; (×) WYK; (●) VASVI. All the samples including the positive control were orally administrated to the SHRs at 50 mg/kg. The values are means ± SD of triplicate experiments. ^### p < 0.001 (positive control compared to non-treated group), ** p < 0.01, *** p < 0.001 (sample group compared to non-treated group).