Alkaloids from Aconitum carmichaelii Alleviates DSS-Induced Ulcerative Colitis in Mice via MAPK/NF-κB/STAT3 Signaling Inhibition

Fuzi (Aconitum carmichaelii Debx) has been traditionally used for the treatment of ulcerative colitis (UC) in China for thousands of years. The total alkaloids of A. carmichaelii (AAC) have been considered as the main medicinal components of fuzi, whereas its underlying anti-UC mechanisms remain elusive. In the present study, the dextran sulfate sodium (DSS)-induced UC mice model, which was consistent with the symptoms and pathological features of human UC, was established to comprehensively evaluate the anti-UC effects of AAC. The results indicated that AAC effectively improved the weight loss, disease activity index (DAI), spleen hyperplasia, and colon shortening, and thus alleviated the symptoms of UC mice. Meanwhile, AAC not only inhibited the MPO enzyme and the abnormal secretion of inflammatory cytokines (TNF-α, IL-1β, IL-6, IFN-γ, and IL-17A) and suppressed the overexpression of inflammatory mediators (TNF-α, IL-1β, and IL-6) of mRNA but also reduced the phosphorylation of p38 MAPK, ERK, and JNK, and the protein expressions of NF-κB, IκB-α, STAT3, and JAK2 in the colon tissue. Furthermore, the LC-MS/MS quantitative determination suggested that the three low toxic monoester alkaloids were higher in both contents and proportion than that of the three high toxic diester alkaloids. Additionally, molecular docking was hired to investigate the interactions between alkaloid-receptor complexes, and it suggested the three monoester alkaloids exhibited higher binding affinities with the key target proteins of MAPK, NF-κB, and STAT3. Our finding showcased the noteworthy anti-UC effects of AAC based on the MAPK/NF-κB/STAT3 signaling pathway, which would provide practical and edge-cutting background information for the development and utilization of A. carmichaelii as a potential natural anti-UC remedy.