Identification of antihypertensive peptides from <i>Eudrilus eugeniae</i> (Kinberg, 1867): in vitro ACE-I inhibition and peptide profiling

Hypertension remains a major global health concern, highlighting the need for the development of safer and more efficacious antihypertensive agents. This study investigated the angiotensin-I converting enzyme (ACE-I) inhibitory activity of bioactive peptides derived from the African Nightcrawler earthworm, <i>Eudrilus eugeniae</i> (Kinberg, 1867) <i>(E. eugeniae)</i>. Crude protein extracts were subjected to enzymatic hydrolysis using pepsin and pancreatin, followed by gel permeation chromatography for fractionation. Among the seven fractions, pooled fraction 6 (PF6), composed of peptides ranging from 917 to 1611 Da with 7-12 amino acid residues, exhibited the highest ACE-I inhibitory activity at 88.3% and an IC₅₀ of 86.76 µg/mL. Peptide sequencing <i>via</i> MALDI TOF-MS/MS identified key sequences containing proline and hydrophobic residues, which may contribute to ACE-I inhibition. These findings suggest that <i>E. eugeniae</i> is a promising natural source of antihypertensive peptides.