Peptides derived from the red alga Gracilariopsis chorda showed 92% inhibition of ACE, a key enzyme targeted by blood pressure medications, with two novel peptide sequences identified as promising inhibitors.
92% ACE inhibitory activityAchieved by thermolysin hydrolysate of water-soluble proteins from red alga G. chorda, with two novel peptide sequences (IDHY and LVVER) identified
What the researchers found
Water-soluble protein from the red alga Gracilariopsis chorda, when hydrolyzed by thermolysin, produced peptides with 92% ACE (angiotensin-converting enzyme) inhibitory activity, substantially outperforming its DPP-IV inhibitory and antioxidant (DPPH scavenging) activities. Two novel ACE-inhibitory peptides were identified: IDHY and LVVER. Molecular docking analysis showed IDHY to be a particularly promising ACE inhibitor. The source proteins — phycobiliproteins and RuBisCo — contain high proportions of hydrophobic (31.0–46.5%) and aromatic (5.1–46.5%) amino acid residues, favorable for ACE-inhibitory peptide generation. Most ACE-inhibitory peptide sequences were located in highly solvent-accessible α-helix regions of the parent proteins.
Why it matters
ACE inhibitors are one of the most important drug classes for treating high blood pressure and heart disease. Discovering natural peptides from marine algae that can inhibit ACE could lead to food-derived alternatives or supplements with blood pressure-lowering potential, and red algae represent an abundant, sustainable source of these bioactive peptides.
The numbers in context
92% ACE inhibition · 2 novel peptides (IDHY, LVVER) · 31.0–46.5% hydrophobic amino acids · 5.1–46.5% aromatic amino acids
How the study worked
Laboratory study. Water-soluble proteins were extracted from the red alga G. chorda and hydrolyzed using thermolysin enzyme. The resulting peptides were tested for ACE inhibitory activity, DPP-IV inhibitory activity, and antioxidant (DPPH scavenging) activity. Novel peptides were identified and their interaction with human ACE was modeled using molecular docking. In silico analysis of the 3D protein structures identified structural features that favor ACE-inhibitory peptide release during digestion.
Who was studied
In vitro study of bioactive peptides derived from the red alga Gracilariopsis chorda
What this study cannot tell us
This is an in vitro and computational study — the ACE inhibitory activity was measured in the lab, not in living organisms. The peptides have not been tested in animal models or human clinical trials, so their actual blood pressure-lowering effect in the body is unknown. Peptide bioavailability (whether they survive digestion and reach the bloodstream intact) was not assessed.
How to read the evidence
This is an in vitro and computational study demonstrating enzyme inhibition in a laboratory setting. While the 92% ACE inhibition is impressive, no animal or human testing has been conducted, so real-world blood pressure effects are unknown.
When this study was published
Published in 2023, this is recent research in the active field of marine-derived bioactive peptides. Interest in algae-sourced functional peptides continues to grow.
The bigger picture
There is growing interest in food-derived bioactive peptides as natural alternatives or complements to pharmaceutical ACE inhibitors for blood pressure management. Marine sources like seaweed are attractive because they are abundant, renewable, and already part of many diets worldwide. This study adds red algae to the growing list of marine organisms that produce potent ACE-inhibitory peptides, alongside fish, shellfish, and microalgae.
Questions still open
- Do these algae-derived peptides survive gastrointestinal digestion and reach the bloodstream in active form?
- Would oral consumption of G. chorda protein hydrolysates actually lower blood pressure in animal models or humans?
- How does the ACE-inhibitory potency of IDHY compare to established food-derived peptides like those from milk (lactotripeptides)?
Common questions
What is ACE and why does inhibiting it matter for blood pressure?
Can eating red seaweed lower blood pressure based on this study?
Read the original research
Characterisation of Bioactive Peptides from Red Alga Gracilariopsis chorda.
Marine drugs, 21(1)
Citation
Mune Mune, Martin Alain; Miyabe, Yoshikatsu; Shimizu, Takeshi; Matsui, Wataru; Kumagai, Yuya; Kishimura, Hideki. (2023). Characterisation of Bioactive Peptides from Red Alga Gracilariopsis chorda.. Marine drugs, 21(1). https://doi.org/10.3390/md21010049