Blood Pressure-Lowering Peptide Discovered in Green Seaweed Survives Digestion

Researchers isolated protein from Ulva prolifera and hydrolyzed it using five commercial enzymes individually and in combination. The hydrolysate with the highest ACE inhibitory activity was purified through gel filtration, ultrafiltration, and HPLC-Q-TOF-MS. Computational ADMET screening and molecular docking were used to characterize the peptide-ACE interaction. Functional assays were performed on human endothelial cells and mouse splenocytes, and gastrointestinal stability was tested with simulated digestion.

Finding natural food-derived peptides that can lower blood pressure is a growing area of research for developing functional foods and nutraceuticals. DIGGL is particularly promising because it comes from an abundant, edible seaweed, works at low concentrations, has multiple beneficial mechanisms (ACE inhibition plus nitric oxide boost), and survives digestion — a major hurdle for oral peptide bioactivity.

This work contributes to the broader effort to develop bioactive peptides from marine sources as natural alternatives or supplements to pharmaceutical ACE inhibitors. Seaweed-derived peptides are particularly attractive because seaweed is abundant, sustainable, and already consumed as food in many cultures. The dual cardiovascular and immunomodulatory activity of DIGGL adds to its potential as a functional food ingredient.

All experiments were conducted in vitro or in cell culture — there are no animal or human studies showing that DIGGL lowers blood pressure when consumed. The gastrointestinal stability test was simulated, not performed in a living system. Bioavailability (whether the peptide is absorbed into the bloodstream) was not assessed. The immunomodulatory effects on splenocytes need further investigation for relevance.