pH-responsive alliin delivery system: sustained intestinal release

Alliin, a natural bioactive compound derived from garlic, exhibits potent antibacterial and antioxidant properties. However, its application in food and medicine is limited by degradation in the acidic gastric environment. In this study, we developed a novel pH-responsive delivery system based on hollow mesoporous silica nanoparticles (HMSNs) encapsulated within sodium alginate-starch (SA/ST) composite gel beads. The HMSNs were synthesized via a soft-template method and loaded with alliin, achieving an encapsulation efficiency of 31.5% and a drug loading capacity of 48.4%. The composite gel beads demonstrated excellent pH-sensitive behavior, with minimal alliin release (9%) in simulated gastric fluid (pH 1.2) and sustained release (91% over 36 h) in simulated intestinal fluid (pH 7). The system exhibited significant antioxidant activity, with DPPH and hydroxyl radical scavenging rates of 80.2% and 57.3%, respectively, comparable to free alliin. Furthermore, the beads showed strong antibacterial effects against Staphylococcus aureus and Escherichia coli , with inhibition rates of 80.65% and 72.73%, respectively, under intestinal conditions. This study highlights the potential of the alliin@HMSNs@SA/ST system as a smart delivery platform for functional foods and nutraceuticals, offering targeted protection and controlled release of bioactive compounds in the gastrointestinal tract.