Seven new ACE-inhibiting peptides were identified from eel bone collagen, with the most potent (GPPGPPGL, IC50 535.84 μM) competitively binding ACE and increasing nitric oxide production in vascular cells.
IC50 535.84 μMGPPGPPGL from eel bone collagen was the most potent ACE inhibitor among 7 novel peptides, with additional vascular protective effects
What the researchers found
Seven novel ACE inhibitory peptides were identified from eel bone collagen hydrolysates, with GPPGPPGL (IC50 535.84 μM) competitively binding ACE's S2 pocket. GPPGPPGL also increased nitric oxide and decreased endothelin-1 in HUVECs.
Why it matters
Finding ACE-inhibiting peptides that also promote blood vessel health offers dual cardiovascular benefits. Using eel bone waste as a source adds economic value to aquaculture byproducts while potentially creating functional food ingredients.
The numbers in context
Multiple ACE-inhibiting peptide sequences identified from eel bone collagen. Molecular docking confirmed binding to ACE active site. HUVEC protection demonstrated against angiotensin II damage.
How the study worked
Eel bone collagen hydrolyzed by alcalase and separated by ultrafiltration. 615 peptides identified via nano-HPLC-MS/MS; 7 ACE-inhibitory peptides screened through molecular docking. Kinetic analysis confirmed competitive inhibition. Vascular effects tested in HUVEC cell culture.
Who was studied
ACE enzyme assays and HUVEC cell culture
What this study cannot tell us
In vitro study only — ACE inhibition in a test tube doesn't guarantee blood pressure lowering in humans. The IC50 of 535.84 μM is relatively high compared to pharmaceutical ACE inhibitors. Bioavailability after oral digestion is unknown.
How to read the evidence
Preliminary evidence from in vitro enzyme assays, molecular docking, and cell culture experiments. No animal or human trials conducted.
When this study was published
Published in 2024; represents current research in marine-derived bioactive peptides.
The bigger picture
Food-derived ACE-inhibitory peptides are a growing area of nutraceutical research. Collagen from fish and marine sources is particularly rich in proline-containing peptides that interact with ACE. The combination of ACE inhibition with direct vascular protection makes these peptides more interesting than simple enzyme blockers.
Questions still open
- Does GPPGPPGL survive gastrointestinal digestion and reach the bloodstream at active concentrations?
- Can eel bone collagen hydrolysates lower blood pressure in animal models or human trials?
- How does the ACE-inhibitory potency of these eel peptides compare to established food-derived ACE inhibitors from milk or soy?
Common questions
Could eating eel help lower blood pressure?
How does this compare to blood pressure medications?
Read the original research
Angiotensin-I-converting enzyme inhibitory peptides from eel (Anguilla japonica) bone collagen: preparation, identification, molecular docking, and protective function on HUVECs.
Frontiers in nutrition, 11, 1462656
Citation
Xiang, Huan; Huang, Hui; Shao, Yanqiu; Hao, Shuxian; Li, Laihao; Wei, Ya; Chen, Shengjun; Zhao, Yongqiang. (2024). Angiotensin-I-converting enzyme inhibitory peptides from eel (Anguilla japonica) bone collagen: preparation, identification, molecular docking, and protective function on HUVECs.. Frontiers in nutrition, 11, 1462656. https://doi.org/10.3389/fnut.2024.1462656