Broad-spectrum ROS autonomous scavenging polysaccharide-based vehicle to improve the bioactivity of blueberry anthocyanidins through intestinal synergistic mucoadhesion

The harsh physiological environment of the gastrointestinal tract can significantly affect the stability, antioxidant activity, and bioactivity of blueberry anthocyanidin (An), which is usually addressed by intestinal targeting co-delivery of An and other antioxidant substances. However, the modification, synthesis of vehicle and subsequent co-encapsulation procedure involved in this tactic are not conducive to practical application. Herein, we propose an easy method of constructing a biocompatible vehicle with broad-spectrum ROS scavenging performance to enhance the bioactivity of An through synergistic intestinal targeted mucoadhesion, that is, a nanogel (Mgel) was prepared by using thiol-contained sodium alginate, selenized konjac glucomannan and crosslinking with calcium lactate for the intestinal targeted delivery of An (Mgel@An). We evaluated the loading behavior of Mgel on An, as well as the enhancement of Mgel on the stability and bioactivity of An. Mgel@An maintained spherical structure in the stomach but disintegrated and exposed functional groups for synergistic mucoadhesion after treatment with simulated intestinal fluids. Mgel@An exhibited broad-spectrum free radical scavenging activity for •OH, •ABTS+ and •DPPH, and also showed a mucin absorbed amount of 162.03 ± 1.53 μg and 85.63 ± 1.40% bioaccessibility of An. Furthermore, the biosafe Mgel@An extended the maximum lifespan of Caenorhabditis elegans by enhancing the activity of antioxidases, inhibiting the expression of aging key genes (daf-2, age-1), and promoting the expression of anti-aging genes (daf-16, sod-3), as well as anti-oxidative stress genes (sod-5, skn-1). This work highlights the great potential of the vehicle with ROS autonomous scavenging behavior for improving the bioactivity of An.