Inhibition of colitis by ring-modified analogues of 6-acetamido-2,4,5-trimethylpyridin-3-ol

Preparation of Oral Core-Shell Zein Nanoparticles to Improve the Bioavailability of Glycyrrhizic Acid for the Treatment of Ulcerative Colitis

In this study, oral colon-targeted adhesion core-shell nanoparticles were designed by applying FA-Zein as the core and using pectin as the shell to enhance the low bioavailability exhibited by glycyrrhizic acid (GA) and the anti-inflammatory effect in specific parts of the intestine. As indicated by the results, the nanoparticles (NPs) remained stable in the stomach and small intestine, while pectins began to degrade and release GA in considerable amounts in the colon with the abundant flora. Subsequently, folate-acid targeting was further assessed with Raw 264.7 and NCM 460 cells. Lastly, NPs were reported to exhibit high adhesion on the colon by using the DSS-induced ulcerative colitis mouse model. Moreover, as indicated by in vitro and in vivo studies, nanoparticles could decrease the levels of MPO and TNF-α by reducing macrophages and neutrophils. In brief, this study provides an ideal loaded natural anti-inflammatory drug delivery system to treat ulcerative colitis.

Novel Pyridine Bioisostere of Cabozantinib as a Potent c-Met Kinase Inhibitor: Synthesis and Anti-Tumor Activity against Hepatocellular Carcinoma

Two novel bioisosteres of cabozantinib, 3 and 4, were designed and synthesized. The benzene ring in the center of the cabozantinib structure was replaced by trimethylpyridine (3) and pyridine (4), respectively. Surprisingly, the two compounds showed extremely contrasting mesenchymal-epithelial transition factor (c-Met) inhibitory activities at 1 μM concentration (4% inhibition of 3 vs. 94% inhibition of 4). The IC₅₀ value of compound 4 was 4.9 nM, similar to that of cabozantinib (5.4 nM). A ligand-based docking study suggested that 4 includes the preferred conformation for the binding to c-Met in the conformational ensemble, but 3 does not. The anti-proliferative activity of compound 4 against hepatocellular carcinoma (Hep3B and Huh7) and non-small-cell lung cancer (A549 and H1299) cell lines was better than that of cabozantinib, whereas 3 did not show a significant anti-proliferative activity. Moreover, the tumor selectivity of compound 4 toward hepatocellular carcinoma cell lines was higher than that of cabozantinib. In the xenograft chick tumor model, compound 4 inhibited Hep3B tumor growth to a much greater extent than cabozantinib. The present study suggests that compound 4 may be a good therapeutic candidate against hepatocellular carcinoma.

Synthesis and activity of N-(5-hydroxy-3,4,6-trimethylpyridin-2-yl)acetamide analogues as anticolitis agents via dual inhibition of TNF-α- and IL-6-induced cell adhesions

Tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) are the critical pro-inflammatory cytokines involved in the pathogenesis of inflammatory bowel disease (IBD). Inhibition of these cytokines and related signaling pathways has been a target for the development of IBD therapeutics. In the current study, 6-acetamido-2,4,5-trimethylpyridin-3-ol (1) and various analogues with the amido scaffold were synthesized and examined for their inhibitory activities in in vitro and in vivo IBD models. The parent compound 1 (1 μM) showed an inhibitory activity against TNF-α- and IL-6-induced adhesion of monocytes to colon epithelial cells, which was similar to tofacitinib (1 μM), a JAK inhibitor, but much better than mesalazine (1,000 μM). All the analogues showed a positive relationship (R² = 0.8943 in a linear regression model) between the inhibitory activities against TNF-α-induced and those against IL-6-induced adhesion. Compound 2-19 turned out to be the best analogue and showed much better inhibitory activity against TNF-α- and IL-6-induced adhesion of the cells than tofacitinib. In addition, oral administration of compound 1 and 2-19 resulted in a significant suppression of clinical signs of TNBS-induced rat colitis, including weight loss, colon tissue edema, and myeloperoxidase activity, a marker for inflammatory cell infiltration in colon tissues. More importantly, compound 2-19 (1 mg/kg) was more efficacious in ameliorating colitis than compound 1 and sulfasalazine (300 mg/kg), the commonly prescribed oral IBD drug. Taken together, the results suggest that compound 2-19 can be a novel platform for dual-acting IBD drug discovery targeting both TNF-α and IL-6 signaling.