Two novel selenium-enriched peptides from oysters boosted nitric oxide release by up to 273% and suppressed the blood vessel constrictor ET-1 more effectively than the ACE inhibitor drug captopril in cell studies.
273% increase in NO releaseThe oyster-derived selenium peptide QASeMNEATGGK boosted nitric oxide release by 273% in blood vessel cells — significantly more than the prescription ACE inhibitor captopril — while also suppressing the blood vessel constrictor ET-1.
What the researchers found
The purified oyster fraction M4-2 had an ACE inhibitory IC50 of 0.774 mg/mL, 3.6 times more potent than the crude hydrolysate (IC50: 2.801 mg/mL). Ninety-one selenium-containing peptide sequences were identified by LC-MS/MS.
The two selected peptides showed strong ACE binding: SeMFRTSSK (-9.8 kcal/mol, binding via hydrogen bonds to active pocket residues) and QASeMNEATGGK (-9.0 kcal/mol, interacting with the Zn²⁺ active center). At 0.025 mg/mL in EA.hy926 endothelial cells, SeMFRTSSK and QASeMNEATGGK enhanced NO release by 202.65% and 273.45% respectively, while suppressing ET-1 secretion by 18.03% and 27.86% — outperforming captopril on both measures. Both peptides were non-cytotoxic up to 0.25 mg/mL.
Why it matters
Hypertension affects over a billion people worldwide and is the leading modifiable risk factor for heart disease and stroke. ACE inhibitor drugs are effective but cause side effects like persistent cough and angioedema. Finding natural ACE-inhibitory peptides from food sources could offer a gentler alternative or complement for blood pressure management. The selenium enrichment adds another dimension — selenium is an essential trace element with antioxidant properties, making these peptides potentially dual-functional.
How the study worked
Selenium-enriched oyster proteins were digested with trypsin and purified through ultrafiltration and two-step reversed-phase HPLC to isolate the most ACE-inhibitory fraction. LC-MS/MS identified 91 selenium-containing peptide sequences. Molecular docking simulations predicted binding interactions with the ACE enzyme. The two most promising peptides were tested in EA.hy926 endothelial cells for cytotoxicity, nitric oxide release, and endothelin-1 secretion, with captopril as the positive control.
What this study cannot tell us
This is an in vitro study using endothelial cell cultures — the peptides have not been tested in animals or humans for actual blood pressure reduction. Oral bioavailability is unknown — the peptides may be degraded during digestion before reaching the bloodstream. The comparison to captopril was in cell culture, not at equivalent systemic doses, so the claim of superiority may not translate in vivo. The selenium content and its specific contribution to bioactivity versus the peptide backbone are not separated. The oyster source requires selenium-enriched cultivation conditions.
How to read the evidence
This is a laboratory study combining biochemical purification, computational molecular docking, and cellular assays. The multi-method approach provides strong mechanistic evidence. However, all results are in vitro — no animal or human blood pressure measurements exist. The comparison to captopril in cell culture doesn't account for pharmacokinetic differences that would exist in vivo.
When this study was published
Published in 2025, this study represents current advances in bioactive peptide discovery from marine sources, combining traditional protein chemistry with computational drug design approaches.
The bigger picture
Food-derived ACE-inhibitory peptides are one of the most studied categories of bioactive peptides, with several already marketed as functional food ingredients. Adding selenium — an essential micronutrient with antioxidant and anti-inflammatory properties — creates a dual-benefit peptide that addresses both blood pressure and oxidative stress. This study exemplifies the growing field of precision nutraceuticals, where specific bioactive peptide sequences are identified, characterized, and validated rather than relying on crude protein hydrolysates.
Questions still open
- Would these selenium-enriched peptides survive gastrointestinal digestion and maintain ACE-inhibitory activity after oral consumption?
- Does the selenium component contribute to the antihypertensive effect, or is the bioactivity purely from the peptide sequence?
- Could these peptides be developed into a functional food product or supplement for blood pressure management?
Common questions
How do these oyster peptides lower blood pressure?
Why are these peptides enriched with selenium?
Read the original research
Identification, Molecular Docking Mechanism and Cellular Activity of Selenium-Enriched ACE Inhibitory Peptides from Oysters.
Molecules (Basel, Switzerland), 30(24)
Citation
Yue, Zhuangzhuang; Xia, Zhen; Xu, Fei; Chen, Bingbing; Jiao, Shufei; Liang, Xingtang; Yin, Yanzhen; Miao, Jianyin. (2025). Identification, Molecular Docking Mechanism and Cellular Activity of Selenium-Enriched ACE Inhibitory Peptides from Oysters.. Molecules (Basel, Switzerland), 30(24). https://doi.org/10.3390/molecules30244818