Antihypertensive effect of quinoa protein under simulated gastrointestinal digestion and peptide characterization

Abstract

BACKGROUND: Quinoa protein is a potential source of bioactive peptides. Although some studies have demonstrated its angiotensin converting enzyme (ACE) inhibitory properties, research into its in vivo effect on blood-pressure regulation and peptide characterization remains limited. RESULTS: Quinoa protein hydrolyzate (QPH) was prepared by simulated gastrointestinal digestion. QPH lowered the systolic blood pressure (SBP) and diastolic blood pressure (DBP) in spontaneously hypertensive model rats (SHRs) from 2 h to10 h after oral administration, effectively controlling blood pressure in these SHRs. An in vitro study showed that QPH is capable of inhibiting ACE activity. This was attributed to the activity of a number of low-molecular-weight peptides. With relatively high scores predicted by PeptideRanker, three promising bioactive peptides, FHPFPR, NWFPLPR, and NIFRPF, were further studied and their ACE-inhibition effects were confirmed with IC 50 values of 34.92, 16.77, and 32.40 ∼M, respectively. A molecular docking study provided insights into the binding of ACE with peptides, and revealed that the presence of specific amino acids in the peptide sequence (Pro, Phe, and Arg at the C-terminal, and Asn at the N-terminal) could contribute to the interaction between ACE and peptides. CONCLUSION: These results demonstrated the potential of QPH for the management of hypertension, which indicates that it could be a good candidate for inclusion in functional foods to control high blood pressure.

Administration with Quinoa Protein Reduces the Blood Pressure in Spontaneously Hypertensive Rats and Modifies the Fecal Microbiota

“…For example, RGQVIYVL, a peptide from quinoa bran albumin, showed a significant antihypertensive effect in SHRs at a concentration of 100 or 150 mg/kg BW [ 22 ]. As reported in our previous study [ 23 ], quinoa protein hydrolysate produced by simulated gastrointestinal digestion showed a potent ACE inhibitory activity, and induced a significant decrease in blood pressure of SHRs between 2 and 10 h after oral administration at the dose of 200 or 400 mg/kg BW. It could be found that both intact and hydrolyzed quinoa protein at the dose of 200 or 400 mg/kg BW have led to a similar maximal blood pressure reduction with 10 mg/kg BW captopril.…”

“…), a pseudocereal that originated in South America, has been recognized as an excellent source of dietary protein due to its high level of protein and well-balanced amino acids composition. Several quinoa protein hydrolysates that prepared by Alcalase, pepsin, trypsin, bromelain, etc., have been reported to possess in vitro ACE inhibitory activity [ 19 , 20 , 21 , 22 , 23 ], and some of them have demonstrated excellent antihypertensive activity in SHRs [ 22 , 23 ]. However, the in vivo antihypertensive effect of intact quinoa protein remains unclear.…”

The functional ingredients of quinoa (Chenopodium quinoa) and physiological effects of consuming quinoa: A review

“…Another in vitro study reported the α‐amylase and α‐glucosidase inhibitory activities of quinoa polysaccharide (Tan et al., 2020). Some quinoa peptides might help blood sugar control as in vitro studies have reported their inhibitory effects against dipeptidyl‐peptidase‐4 (DPP‐IV), α‐amylase and α‐glucosidase (Guo, Richel, et al., 2020; Mudgil et al., 2020; Nongonierma et al., 2015; Vilcacundo et al., 2017). DPP‐IV inhibitors are used in type 2 diabetes treatment as they can help reduce postprandial and fasting hyperglycemia by prolonging the secretion of insulin (Green et al., 2006; Kasina & Baradhi, 2019).…”

“…One type of the ingredients responsible for this effect may be the bioactive peptides found in quinoa. Several peptides in quinoa have shown ACE‐inhibitory activity (Guo, Richel, et al., 2020; Obaroakpo et al., 2020; Zheng et al., 2019). A specific bioactive peptide (RGQVIYVL) identified in the study by Zheng et al.…”

“…No significant change in blood pressure has been observed in several studies (Farinazzi‐Machado et al., 2012; Li et al., 2018; Pourshahidi et al., 2020). Although oral administration of quinoa protein hydrolysate has been reported to lower the blood pressure of hypertensive model rats (Guo, Hao, et al., 2020), consuming the whole grain of quinoa seems to have little effect on blood pressure, probably due to the dilution of functional components.…”