Sodium alginate coated ferritin as ACE inhibitory peptide carrier: Prolonged release property and enhanced transepithelial transport.

Unlabelled: The application of Ala-His-Leu-Leu (AHLL), an angiotensin converting enzyme (ACE) inhibitory peptide, is limited due to its low stability. In this work, horse spleen apoferritin (HSF) deposited with a layer of sodium alginate (SA) was employed to carry AHLL. The HSF encapsulation and SA decoration exhibited remarkable protection capacity for loaded AHLL from UV irradiation and thermal treatment. The ACE inhibitory activity of AHLL-HSF@SA nanoparticles maintained 60%-75% within the digestion process since the compact structure and the coverage of enzyme reaction sites. Intestinal permeability investigation unveiled that HSF encapsulation facilitated the AHLL absorption, and the value was (2.70 ± 0.02) × 10 cm/s. Moreover, the transepithelial transport of free AHLL was primarily mediated through the paracellular pathway, whereas the transport of AHLL-HSF nanoparticles might rely on AP2-mediated endocytosis. Owing to positive effects on structural stability, release property and intestinal absorption, polysaccharides coated ferritin is a promising vehicle for peptides.

Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-025-01826-x.