Lipid–Polymer Hybrid Nanoparticles for Oral Delivery of Tartary Buckwheat Flavonoids

Flavonoids rich in Tartary buckwheat (TBFs) are the acknowledged health-promoting substances, even with the low oral bioavailability due to its chemical instability in gastrointestinal tract and poor intestinal absorption. To obtain the enhanced oral delivery, TBFs, obtained by an environmentally friendly extraction strategy in advance with the amount of 7.66 ± 0.47 mg rutin/g, was incorporated in biocompatible lipid-polymer hybrid nanoparticles (LPNs). Its high encapsulation efficiency of 96.4% ± 1.1%, narrow size distribution of 61.25 ± 1.83 nm with spherical shape, and good storage stability were observed. Compared to free TBFs, TBFs/LPNs exhibited higher antioxidant activity and significant suppression on the pro-inflammatory cytokine secretion in RAW 264.7 macrophage. Moreover, the enhanced delivery of TBFs/LPNs was also embodied in the improved transmembrane transport in Caco-2 monolayer, suggesting its better intestinal absorption, and significantly immune-enhancing efficacy in immunosuppressed mice. These results demonstrated the new perspectives of Tartary buckwheat flavonoids-loaded nanosystem for pharmaceutical and nutraceutical applications.