VPPIPP and IPPVPP: Two Hexapeptides Innovated to Exert Antihypertensive Activity

In this study, two hexapeptides of IPPVPP and VPPIPP were innovated by using two commercial antihypertensive peptides IPP and VPP as two domains cis-linked and trans-linked, respectively. The IPPVPP and VPPIPP were chemically synthesized and evaluated for the antihypertensive activity in vitro/vivo. The in vitro ACE-inhibitory study showed that VPPIPP (34.71 +/- 4.38%) has a significantly stronger activity than that of IPPVPP (13.17 +/- 0.25%) at a treatment concentration of 10 mu mol/L, but it was weaker than the commercial IPP (56.97 +/- 2.40%) (P<0.05). However, VPPIPP, IPPVPP, and IPP lowered the systolic blood pressure by 21 +/- 0.9%, 17.4 +/- 1.3% and 17.5 +/- 0.9%, respectively, in rats at 1.5 mg/kg body weight dosage. The result was consistent with the mRNA level of sarcoplasmic reticulum Ca2+, Mg2+-ATPase Gene (SERCA 2a) in rat hearts. Additionally, VPPIPP and IPPVPP showed no negative impact on blood glycometabolism. The results suggested that the two hexapeptides could be potent bioactive peptides in functional foods for people with high blood pressure.