Pullulan-stabilized gliadin nanocomplexes loaded with astragaloside IV: Fabrication, characterization and treatment of ulcerative colitis

Astragaloside IV (ASIV) is a triterpenoid saponin with promising potential in treating ulcerative colitis (UC), but its efficacy is hindered by poor solubility and rapid systemic clearance. Gliadin, an amphiphilic protein, has been widely used as a nanocarrier. Here, the novel edible pullulan-stabilized gliadin nanocomplexes (PL-Gli NPs) were developed to deliver ASIV. Interaction force analysis revealed that the formation of PL-Gli NPs involved in electrostatic interaction, hydrophobic interaction, and hydrogen bonding. ASIV was encapsulated into PL-Gli NPs via hydrophobic interaction to form ASIV-loaded nanocomplexes (ASIV@PL-Gli NPs). The resulting nanocomplexes had a particle size of (381.5 ± 5.3) nm and high encapsulation efficiency of 93.00 %. Notably, the stability of ASIV@PL-Gli NPs was improved under harsh conditions owing to the incorporation of pullulan. Furthermore, ASIV@PL-Gli NPs exhibited sustained release, with only 63.69 % cumulative release of ASIV at 10 h. Importantly, ASIV@PL-Gli NPs markedly enhanced anti-UC efficacy of ASIV, evidenced by a 51.81 % increase in colon length, a 53.16 % reduction in disease activity index scores, and significant decreases in pro-inflammatory cytokine levels. This work first employs pullulan and gliadin as oral nanocarriers for the delivery of ASIV, providing great potential for functional foods in UC treatment.