ROS-responsive microcapsule assembly from Turkish galls for ulcerative colitis therapy

Abstract

Ulcerative colitis (UC) is a chronic, relapsing but nonspecific inflammatory bowel disease (IBD) that poses clinical challenges, as the fabrication of a safe, effective, and economical drug delivery system is still one of the biggest difficulties in drug therapy for UC. Herein, a galltannin-metal microcapsule (GTA–Fe^III MCP) system coupled active constituents of Turkish gall and Fe^III (Fe is one of the trace elements certified by the WHO) is reported for UC therapy. The hollow GTA–Fe^III MCPs contain 4 categories of phenolic ligands, with an average particle size of 1.5 ± 0.5 μm and a double shell thickness of 38.1 ± 2.5 nm. When the concentration of the GTA–Fe^III MCPs was greater than 250 μg mL⁻¹, the H₂O₂ level decreased dramatically with the increase of incubation time and the GTA–Fe^III MCPs gradually disassembled, demonstrating the anti-oxidant properties of GTA–Fe^III MCPs, as well as their sensitivity and responsiveness to H₂O₂. Furthermore, the effects of anti-inflammatory and therapeutic efficacy against UC of GTA–Fe^III MCPs had been confirmed. In vitro, IL-6, IL-1β, NO, TNF-α, and ROS levels were reduced by GTA–Fe^III MCPs. In vivo, UC symptoms were ameliorated in mice given GTA–Fe^III MCPs according to the disease activity index (DAI), colonic length shortening and pathological damage, myeloperoxidase (MPO) activity, and production of pro-inflammatory mediators. Consequently, this study provides a candidate drug carrier for anti-UC therapeutics, as well as new insights into the robustness of natural phenolic mixtures and solution-based metal sources.