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

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 mu m and a double shell thickness of 38.1 +/- 2.5 nm. When the concentration of the GTA-Fe-III MCPs was greater than 250 mu g 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-1 beta, NO, TNF-alpha, 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.