Purification and Characterization of Angiotensin-I Converting Enzyme Inhibitory Peptides from Prickly Ash (Zanthoxylum bungeanum Maxim) Seed Protein Hydrolysates

Abstract

Abstract Prickly ash (Zanthoxylum bungeanum Maxim) seed protein was hydrolyzed with papain to obtain hydrolysates with inhibitory activity against angiotensin-I converting enzyme (ACE). ACE inhibitory peptides (ACEIPs) were successfully purified from seed protein hydrolysates through ultrafiltration and gel chromatography. In vitro ACE inhibitory assay revealed an IC50 value of 0.032± 0.008 mg·mL−1 for a component with <5 kDa molecular weight. Four fractions were isolated by Sephadex G-25 gel chromatography under the following elution conditions: flow rate, 0.6 mL·min−1; initial volume, 2.0 mL; and sample concentration, 30 mg·mL−1. The second fraction showed the highest inhibitory activity with an IC50 value of 0.021±0.007 mg·mL−1. The stability of the ACE inhibitory activity of the obtained ACEIPs was identified under storage conditions with varied temperature, pH, and gastrointestinal protease digestion. Peptides derived from prickly ash seed protein hydrolysates may be a potential resource for exploring functional food or pharmaceuticals against hypertension.