Metabolomics profiling and anti-colitic activity of Rudbeckia hirta aerial parts: Inhibition of NF-κB, cytokine storm, and chemokine-mediated immune cell recruitment.

ETHNOPHARMACOLOGICAL RELEVANCE: Ulcerative colitis (UC) is an inflammatory disorder characterized by oxidative stress and dysregulated immune responses. Rudbeckia hirta has been traditionally utilized in Native American medicine for the management of inflammatory conditions and digestive ailments.

OBJECTIVE

Hence, the present study was established to investigate the protective potentials of Rudbeckia hirta aerial parts methanolic extract (RHME) against colitis in rats, with comprehensive phytochemical analyses.

METHODS

RHME was subjected to LC/MS/MS and GC/MS analyses to provide complete phytochemical constituents profile. Colitis was induced in rats via intrarectal administration of 4% acetic acid on day 7. RHME (100 and 200 mg/kg) or sulfasalazine (100 mg/kg) was orally administered for 7 consecutive days. To elucidate the underlying mechanisms of action of RHME, key biomarkers associated with inflammation, particularly the NF-κB and C-X-C motif chemokine signaling pathway, as well as oxidative stress parameters were assessed through performing biochemical, molecular, and immunohistochemical investigations.

RESULTS

GC/MS analysis identified 30 compounds in the hexane fraction, with friedelin as the predominant constituent (37.43%), while LC/MS/MS profiling of the defatted fraction tentatively identified 64 compounds, mainly flavonoids, phenolic acid derivatives, and fatty acids. p-Coumaric acid and caffeic acid were additionally isolated by TLC. RHME was reported to be safe up to the dose 2000 mg/kg rat bw, as verified by the acute oral toxicity test. RHME (200 mg/kg) significantly alleviated colonic damage, preserving mucosal architecture and reducing inflammatory infiltration. Biochemically, RHME dose-dependently restored redox balance by decreasing malondialdehyde levels and enhancing reduced glutathione content in the colon. Furthermore, RHME exerted potent anti-inflammatory effects by suppressing NF-κB activation, consequently inhibiting release of pro-inflammatory mediators, including TNF-α, IL-6, IL-17A, and IFN-γ in the colonic tissues. It also downregulated the expression of CXCL10 gene and its receptor CXCR3, indicating reduced immune cell recruitment.

CONCLUSION

RHME exhibits a multi-target protective effect against colitis through modulation of NF-κB and CXCL10/CXCR3 inflammatory pathways, alongside maintaining redox hemostatic balance. These effects are likely attributed to the synergistic action of bioactive constituents. Hence, RHME could offer a promising natural therapeutic candidate for UC.