Dehydroandrographolide succinate alleviates ulcerative colitis via regulating RAB9A/NF-κB axis-mediated macrophage polarization and remodeling the gut microbiota.
Liu J, Mai Y, et al. • Phytomedicine : international journal of phytotherapy and phytopharmacology • 2026
Dehydroandrographolide succinate alleviates DSS-colitis by targeting RAB9A to block the NF-κB signaling pathway-driven M1 macrophage polarization, and is accompanied by gut microbiota remodeling, highlighting the promising application of DAS against UC.
Key Findings
Results
DAS attenuated clinical features of DSS-induced colitis including weight loss, diarrhea, rectal bleeding, and colon shortening.
The study used a DSS-induced colitis mouse model to evaluate DAS efficacy.
DAS treatment reduced inflammatory infiltrates and restored crypt architecture in colon tissue.
DAS down-regulated pro-inflammatory cytokines IL-1β, IL-6, and TNF-α.
DAS up-regulated anti-inflammatory mediators IL-10 and IL-13.
DAS restored tight-junction proteins ZO-1 and Occludin, as well as goblet-cell mucins.
Results
The therapeutic effect of DAS on colitis is macrophage-dependent, as confirmed by macrophage depletion and adoptive macrophage transfer (AMT) experiments.
Macrophage depletion abolished DAS's therapeutic benefit in the colitis model.
Adoptive macrophage transfer (AMT) using DAS-treated macrophages relieved colitis features in recipient mice.
These experiments confirmed that macrophages are the critical cellular mediator of DAS's anti-colitis activity.
DAS inhibited M1 macrophage polarization and protected epithelial monolayers from macrophage-mediated damage in vitro.
Results
DAS exerts its anti-inflammatory activity primarily by suppressing the NF-κB signaling pathway, specifically by inhibiting p65 phosphorylation and its downstream targets.
Transcriptomics analysis of LPS/IFN-γ-stimulated THP-1-derived macrophages identified the NF-κB signaling pathway as the main mechanism.
DAS suppressed p65 phosphorylation and downstream NF-κB targets.
Transcriptomic findings were followed by experimental verification.
DAS inhibited M1 polarization in the LPS/IFN-γ-stimulated THP-1-derived macrophage model in vitro.
Results
DAS exhibits high-affinity binding to RAB9A, and RAB9A knockdown abolished DAS-mediated suppression of the TLR4/NF-κB signaling pathway in macrophages.
RAB9A was identified as a direct molecular target of DAS using DARTS, CETSA, molecular docking, and molecular dynamics approaches.
DAS demonstrated high-affinity binding to the RAB9A protein.
RAB9A knockdown experiments confirmed that RAB9A is required for DAS's suppression of TLR4/NF-κB signaling.
This identifies the RAB9A/NF-κB axis as the mechanistic basis for DAS's macrophage-directed anti-inflammatory activity.
Results
DAS treatment remodeled the gut microbiota composition, enriching beneficial bacteria and depleting potentially harmful species.
Metagenomic sequencing was used to analyze the effect of DAS on gut microbiota.
DAS enriched Lachnospiraceae bacterium, Duncaniella freteri, Lachnospiraceae bacterium 10-1, Bacterium 1XD8-76, and Schaedlerella arabinosiphila.
DAS depleted Muribaculaceae bacterium, Bacteroides intestinalis, and Clostridiaceae bacterium.
Functional gene profiling indicated DAS upregulated genes related to butyrate metabolism, amino sugar and nucleotide sugar metabolism, and starch and sucrose metabolism.
What This Means
This research suggests that dehydroandrographolide succinate (DAS), a compound isolated from the medicinal plant Andrographis paniculata, can effectively reduce inflammation and tissue damage in a mouse model of ulcerative colitis (UC). In treated mice, DAS reduced common symptoms such as weight loss, diarrhea, rectal bleeding, and colon shortening, while also restoring the structural integrity of the colon lining. The compound lowered levels of inflammation-promoting proteins and raised levels of inflammation-dampening ones, and it helped preserve the protective mucus layer and barrier proteins that keep the gut lining intact.
This research suggests that the key to DAS's effectiveness lies in its ability to control a specific type of immune cell called macrophages. When macrophages were removed from the mice, DAS lost its therapeutic benefit—and when macrophages that had been pre-treated with DAS were transferred into sick mice, those mice improved. DAS works by binding directly to a protein called RAB9A inside macrophages, which in turn blocks a major inflammation-driving pathway called NF-κB, preventing macrophages from taking on a highly inflammatory state known as M1 polarization.
Beyond its effects on immune cells, this research suggests that DAS also reshapes the community of bacteria living in the gut. Treatment with DAS increased the presence of bacteria associated with beneficial functions such as producing butyrate (a short-chain fatty acid important for gut health) and decreased the abundance of potentially harmful bacterial species. Together, these findings point to DAS as a multi-targeted therapeutic candidate for ulcerative colitis that acts on both immune regulation and the gut microbial environment.
Liu J, Mai Y, Xie Y, Zhou X, Ye Y, Jiang D, et al.. (2026). Dehydroandrographolide succinate alleviates ulcerative colitis via regulating RAB9A/NF-κB axis-mediated macrophage polarization and remodeling the gut microbiota.. Phytomedicine : international journal of phytotherapy and phytopharmacology. https://doi.org/10.1016/j.phymed.2026.158039