Simulated digestion of hen egg white lysozyme released 38 peptides with potent ACE-inhibitory activity (IC50 = 12.6 μg/ml) and antioxidant properties, suggesting eggs could be a source of cardiovascular-supporting peptides.
IC50 = 12.6 μg/mlThe lysozyme digest inhibited ACE at a very low concentration, comparable to some pharmaceutical-grade ACE inhibitors
What the researchers found
When hen egg white lysozyme was digested in a simulated gut environment, the resulting peptide fragments showed strong ACE-inhibitory activity with an IC50 of 12.6 μg/ml — meaning a very low concentration was needed to block half the activity of the blood-pressure-raising enzyme ACE. The digest also showed remarkable antioxidant activity.
Using mass spectrometry, the researchers identified 38 distinct peptides in the digest. Several of these matched the known structural requirements for ACE inhibition and antioxidant function, suggesting egg white lysozyme is a rich source of multifunctional bioactive peptides.
Why it matters
ACE inhibitors are one of the most widely prescribed classes of blood pressure medication. Finding natural food-derived peptides with ACE-inhibitory and antioxidant properties could lead to functional foods or supplements that support cardiovascular health through everyday diet — offering a complementary approach to pharmaceutical treatment.
The numbers in context
IC50 = 12.6 μg/ml for ACE inhibition · 38 peptides identified · 3 kDa membrane filtration · simulated gastrointestinal digestion
How the study worked
Researchers subjected hen egg white lysozyme to simulated gastrointestinal digestion (mimicking the stomach and intestine). The resulting peptide fragments were filtered through a 3 kDa membrane, and the smaller peptides that passed through were analyzed using MALDI-TOF-TOF mass spectrometry to identify individual peptide sequences. ACE-inhibitory and antioxidant activities were measured in vitro.
Who was studied
In vitro study using hen egg white lysozyme
What this study cannot tell us
This is entirely an in-vitro study — the ACE inhibition and antioxidant effects were measured in test tubes, not in living organisms. Whether these peptides survive real human digestion, get absorbed into the bloodstream, and actually lower blood pressure remains unknown. No animal or human studies were conducted.
How to read the evidence
This is a preliminary in-vitro study that identifies peptides and measures their activity in test tubes. No living organism was tested, so the real-world relevance of these findings remains to be established.
When this study was published
Published in 2012, this study is part of the foundational research on food-derived ACE-inhibitory peptides. The field has advanced since, but the peptide identification data remains cited in current literature.
The bigger picture
Food-derived bioactive peptides are a rapidly growing area of research, with scientists looking for natural alternatives or supplements to pharmaceutical interventions for hypertension and oxidative stress. Egg proteins are abundant and inexpensive, making them attractive candidates for functional food development. This study adds lysozyme to the list of food proteins that can generate health-promoting peptides during normal digestion.
Questions still open
- Do these peptides survive real human digestion and get absorbed intact into the bloodstream?
- Could consuming egg white lysozyme in meaningful amounts actually lower blood pressure in people?
- How do these egg-derived ACE-inhibitory peptides compare in potency to those from milk, fish, or soy proteins?
Common questions
What is ACE and why does inhibiting it matter for blood pressure?
Does eating eggs actually lower blood pressure based on this study?
Read the original research
ACE inhibitory peptides and antioxidant peptides derived from in vitro digestion hydrolysate of hen egg white lysozyme.
Food chemistry, 135(3), 1245-52
Citation
Rao, Shengqi; Sun, Jun; Liu, Yuntao; Zeng, Huawei; Su, Yujie; Yang, Yanjun. (2012). ACE inhibitory peptides and antioxidant peptides derived from in vitro digestion hydrolysate of hen egg white lysozyme.. Food chemistry, 135(3), 1245-52. https://doi.org/10.1016/j.foodchem.2012.05.059