Blood Pressure-Lowering Peptides Discovered in Sardine Protein That Also Act as Antioxidants | Research

The takeaway

Researchers identified novel ACE-inhibitory and antioxidant peptides from sardine protein hydrolysate using mass spectrometry and molecular docking, suggesting sardines as a source of natural functional food ingredients.

Dual ACE + antioxidant activity
Sardine protein-derived peptides showed both blood pressure-lowering (ACE inhibitory) and antioxidant properties, targeting multiple cardiovascular risk factors

What the researchers found

Sardina pilchardus protein hydrolysate (SPH) produced using dispase and alkaline protease yielded peptide fractions with ACE inhibitory activity, with the low molecular mass fractions showing the strongest effects. The peptides also exhibited antioxidant properties.

Using LC-MS/MS combined with online database searching and molecular docking, the researchers identified novel peptide sequences with strong predicted binding to the ACE enzyme. The dual functionality — both ACE inhibition and antioxidant activity — makes these peptides particularly interesting for functional food development targeting cardiovascular health.

Why it matters

High blood pressure is a leading risk factor for heart disease and stroke. While ACE inhibitor drugs are effective, they can have side effects. Food-derived ACE inhibitory peptides offer a natural alternative that could be incorporated into functional foods or supplements. Sardines are inexpensive and widely available, making them a practical source for these bioactive peptides. The combined ACE inhibitory and antioxidant properties address multiple cardiovascular risk factors simultaneously.

How the study worked

Sardine (Sardina pilchardus) proteins were hydrolyzed using dispase and alkaline protease enzymes. The hydrolysate was fractionated by molecular weight. ACE inhibitory activity and antioxidant capacity were measured for each fraction. LC-MS/MS (liquid chromatography-tandem mass spectrometry) was used to identify individual peptide sequences. Molecular docking simulations modeled the binding interactions between identified peptides and the ACE enzyme to predict and explain their inhibitory activity.

What this study cannot tell us

This is entirely an in vitro and computational study — no animal or human testing was performed. The abstract is incomplete (appears truncated), making it difficult to assess the full scope of results. Specific peptide sequences, IC50 values for ACE inhibition, and antioxidant assay results are not provided in the available abstract. The stability of these peptides during digestion and their bioavailability after oral consumption are unknown. Clinical blood pressure effects would need to be demonstrated in human trials.

How to read the evidence

This is an in vitro and computational study representing early-stage bioactive peptide discovery. While the analytical methods (LC-MS/MS, molecular docking) are appropriate and the discovery pipeline is well-designed, no biological testing in animals or humans was performed. The evidence establishes candidate peptides but not therapeutic proof.

When this study was published

Published in 2023, this study reflects the current state of food-derived bioactive peptide research, using modern analytical and computational tools for peptide discovery and characterization.

The bigger picture

Food-derived bioactive peptides are a rapidly growing field at the intersection of food science and medicine. ACE inhibitory peptides have been discovered in many food sources including milk, eggs, and fish, and some have been commercialized as functional food ingredients. This study adds sardine-derived peptides to this portfolio and demonstrates a modern discovery pipeline (LC-MS/MS + molecular docking) that accelerates identification compared to traditional trial-and-error approaches.

Questions still open

Would these sardine-derived ACE inhibitory peptides survive gastrointestinal digestion and remain active when consumed as food?
How do the IC50 values of these peptides compare to established food-derived ACE inhibitors like those from milk casein?
Could a sardine-based functional food product provide clinically meaningful blood pressure reduction in hypertensive individuals?

Common questions

Can eating sardines lower blood pressure?

This study found that peptides from sardine protein can inhibit ACE, the same enzyme targeted by blood pressure medications. However, the research was done in the lab, not in humans. Whether eating sardines provides enough of these specific peptides to meaningfully lower blood pressure would require clinical studies to determine.

How were the blood pressure-lowering peptides found?

Researchers broke down sardine proteins with enzymes, then used mass spectrometry to identify the individual peptide fragments. They used computer modeling (molecular docking) to simulate how each peptide interacts with the ACE enzyme, selecting the peptides that fit most tightly into the enzyme's active site — similar to how a key fits a lock.

Read the original research

Identification and Characterization of Novel ACE Inhibitory and Antioxidant Peptides from Sardina pilchardus Hydrolysate.

Foods (Basel, Switzerland), 12(11)

View on PubMed ↗Publisher’s paper ↗

Citation

Shao, Mingyang; Wu, Haixing; Wang, Bohui; Zhang, Xuan; Gao, Xia; Jiang, Mengqi; Su, Ruiheng; Shen, Xuanri. (2023). Identification and Characterization of Novel ACE Inhibitory and Antioxidant Peptides from Sardina pilchardus Hydrolysate.. Foods (Basel, Switzerland), 12(11). https://doi.org/10.3390/foods12112216