TNF and ulcerative colitis: Compared to the normal RAW264.7 cells, lipopolysaccharide (LPS)‐treated cells expressed a significantly higher level of TNF‐α (Figure 7D), a proinflammatory cytokine that is mainly secreted by macrophages during the onset and progression of ulcerative colitis.38 Pretreatment with Ac2‐26, Ac2‐26/ON mixture, and different Ac2‐26‐containing NPs effectively reduced the TNF‐α levels in macrophages treated with LPS (Figure 7D and Figure S26B, Supporting Information).