Hypotensive and Physiological Effect of Angiotensin Converting Enzyme Inhibitory Peptides Derived from Soy Protein on Spontaneously Hypertensive Rats

Abstract

Angiotensin converting enzyme (ACE) inhibitory peptides prepared from soy protein by the action of alcalase enzyme was tested for its hypotensive effect on spontaneously hypertensive rats (SHR). Captopril, an ACE inhibitor used widely for hypertension treatment, was also applied in comparison. A significant (p < 0.05) decrease in systolic blood pressure of SHR was observed when soy ACE inhibitory peptides were orally administrated at three different dose levels (100, 500, and 1000 mg/kg of body weight/day), whereas little change occurred in the blood pressure of normotensive rats even at the highest dose. After a month-long feeding, blood pressure readings of SHR fell by approximately 38 mmHg from the original level at the lowest dose; a steadily and progressively hypotensive effect existed for these soy ACE inhibitory peptides administration groups. An obvious fluctuation was observed at the third week, although Captopril had a stronger hypotensive effect. The ACE activity of serum, aorta and lung, and lipid content of serum of SHR upon administration of soy ACE inhibitory peptides did not show a significant difference from that of the control group, whereas the serum ACE activity increased and the aorta ACE activity decreased significantly (p < 0.05) for the Captopril group. Serum Na(+) concentration decreased significantly in both the peptides-treated groups and the Captopril-treated group in comparison with the control group, whereas no lowering effect was observed for serum K(+) and serum Ca(2+) concentrations. These results suggested that the hypotensive effect of ACE inhibitory peptides derived from soy protein could be at least partly attributed to the action on salt/water balance.

Preparation of bioactive peptides with high angiotensin converting enzyme inhibitory activity from winged bean [Psophocarpus tetragonolobus (L.) DC.] seed

“…This indicates that both proteases could give rise to highly active ACE inhibitory peptides. Although the ACE inhibitory activity cannot be directly compared with data under different measuring conditions, the hydrolysates in this study showed a higher or similar activity than other hydrolysates already reported (Wu and Ding 2001;Suh 2000). Several enzymes have been used to produce seed legume protein hydrolysates having bioactive properties.…”

“…Proximate composition of winged bean seeds used in the present study is presented in Table 1 (Yust et al 2003), lentil seed (26 %) (Boye et al 2010), corn gluten (3.22 %) (Kim et al 2004) and soybean (36.49 %) (Wu and Ding 2001), it can be concluded that winged bean seed is a good source of protein for production of bioactive peptides. Overall, the defatting process clearly improves DWBS protein content compared to its original state.…”

“…The bioactive potential of low-molecular weight peptides is high because small peptides can be absorbed in the intestine without being decomposed by digestive enzymes and then reach target sites in the body. According to a study by Wu and Ding (2001), soybean which is quite similar with winged bean seed in having ACE inhibitory activity comprised of oligopeptides with 2-8 amino acid residues. The results of DH, Fig.…”

Preparation of Subcritical Water-Treated Okara and Its Effect on Blood Pressure Spontaneously Hypertensive Rats

“…Wu & Ding (2001) have demonstrated that ACE inhibitory peptides prepared from soy protein by the action of alcalase enzyme decreased SBP when peptides were orally administered to SHR. Although okara contains about 250/0 protein, and the ACE inhibitory peptides could be recovered from okara (Yamauchi et al, 1994), there is little information on the effect of okara on SHR.…”

Lactic Fermentation and Bioactive Peptides

“…Soybean-derived products contain isoflavones, which are thought to possess a favourable effect in reducing cardiovascular risk factors as well as vascular function [78]. However, on the basis of in vitro results and literature review, Wu and Muir [79] have indicated that the contribution of isoflavones to a blood-pressure-lowering effect in soybean ACEI peptides may be negligible. Similarly, it has been reported that the reduction of hypertension of a fermented product from soy milk was contributed mainly by peptides of 800-900 Da but it could be also attributable to GABA [80].…”