The novel tuna-derived peptide LTGCP inhibits ACE with IC50 of 64.3 μM through mixed-type inhibition, forms a stable complex with ACE via seven hydrogen bonds, and remains active after simulated gastrointestinal digestion — making it a practical candidate for antihypertensive supplements.
IC50: 64.3 μM + GI-stableLTGCP maintains ACE-inhibitory activity after simulated gastrointestinal digestion — solving the critical stability challenge for food-derived blood pressure peptides
What the researchers found
The novel tuna muscle peptide LTGCP inhibits ACE (IC50: 64.3 μM) through mixed-type inhibition, forming a stable 7-hydrogen-bond complex, and retains activity after gastrointestinal digestion with no intestinal cell toxicity.
Why it matters
Finding ACE inhibitors that survive digestion is the critical bottleneck for food-derived blood pressure peptides. LTGCP's demonstrated stability through simulated gastrointestinal conditions, combined with its non-toxicity, makes it one of the more practically viable food-derived ACE inhibitors reported — a genuine candidate for nutraceutical development.
The numbers in context
5 novel ACE-I peptides identified; two-step enzymatic hydrolysis; multiple purification steps; Q-Orbitrap-MS/MS identification.
How the study worked
Two-step enzymatic hydrolysis (Neutrase + Alkaline) of tuna muscle. Purification by ultrafiltration, gel chromatography, and RP-HPLC. Peptide identification by Q-Orbitrap-MS/MS. ACE inhibition kinetics, molecular docking, molecular dynamics simulation. Stability testing under heat, pH, and simulated GI digestion. Caco-2 cytotoxicity assay.
Who was studied
In vitro analysis of tuna muscle protein hydrolysates
What this study cannot tell us
In vitro study only — no animal or human blood pressure measurements. Simulated GI digestion doesn't perfectly replicate in vivo conditions. Whether LTGCP is actually absorbed across the intestinal wall (bioavailability) wasn't tested. The IC50 of 64.3 μM, while respectable, means substantial amounts would need to be consumed. Molecular dynamics simulations are computational predictions.
How to read the evidence
Preliminary — in vitro ACE inhibition with computational modeling and stability testing. No animal or human blood pressure studies. The GI stability data is encouraging but needs in vivo confirmation.
When this study was published
Published in 2024, contributing to the growing library of characterized fish-derived ACE-inhibitory peptides.
The bigger picture
The quest for food-derived ACE inhibitors that can survive digestion and reach the bloodstream is one of the most active areas in functional food research. LTGCP stands out because it passes three critical tests: potent ACE inhibition, stability through simulated digestion, and safety for intestinal cells. This makes tuna muscle hydrolysates a promising source material for antihypertensive nutraceuticals or functional foods.
Questions still open
- Is LTGCP absorbed across the intestinal epithelium and does it reach the bloodstream at sufficient concentrations to lower blood pressure?
- What amount of tuna muscle hydrolysate would a person need to consume for an antihypertensive effect?
- How does LTGCP compare to other fish-derived ACE inhibitors in animal blood pressure studies?
Common questions
Could eating tuna help lower blood pressure?
What makes LTGCP special compared to other food peptides?
Read the original research
Angiotensin converting enzyme (ACE) inhibitory peptide from the tuna (Thunnus thynnus) muscle: Screening, interaction mechanism and stability.
International journal of biological macromolecules, 279(Pt 4), 135469
Citation
Wang, Shu; Zhang, Lu; Wang, Hui; Liu, Jiaojiao; Hu, Yueming; Tu, Zongcai. (2024). Angiotensin converting enzyme (ACE) inhibitory peptide from the tuna (Thunnus thynnus) muscle: Screening, interaction mechanism and stability.. International journal of biological macromolecules, 279(Pt 4), 135469. https://doi.org/10.1016/j.ijbiomac.2024.135469