Genipin-crosslinked human serum albumin coating using a tannic acid layer for enhanced oral administration of curcumin in the treatment of ulcerative colitis

•Oral food-grade NPs, composed of TA, HSA and Gnp, encapsulated CUR to treat UC.•The TA surface layer provided gastric protection and colon adherence.•Gnp is a natural and harmless cross-linker used to crosslink HSA in study.•TA/CUR-NPs showed the good anti-inflammatory effect via TLR4/NFκB signaling pathway. Curcumin (CUR) is a promising edible phytochemical compound with ideal ulcerative colitis (UC) treatment activity; however, it is characteristically instable in the digestive tract and has a short retention time in colon. Therefore, we designed and fabricated an oral food-grade nanocarrier composed of tannic acid (TA)-coated, Genipin (Gnp)-crosslinked human serum albumin (HSA) to encapsulate CUR (TA/CUR-NPs). The resulting CUR nanoparticles (NPs) were about 220 nm and −28.8 mV. With the assistance of TA layer and Gnp-crosslinking, the entire nano-scaled system effectively delayed CUR release in simulated gastric fluid, prolonged its colon adhesion and increased its uptake in Caco-2 cells. As expected, TA/CUR-NPs oral administration significantly alleviated colitis symptoms in DSS-treated mice when compared with controls by inhibiting the TLR4-linked NF-κB signaling pathway. Collectively, this study indicates that we have developed a convenient, eco-friendly, nano-scaled vehicle for oral delivery of CUR with anti-UC benefit.