Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) characterized by continuous mucosal inflammation extending from the rectum to the more proximal colon. Its primary symptoms include abdominal pain, diarrhea often accompanied by mucus, and bloody stools (Ordás et al., 2012). In recent years, the incidence of UC has significantly increased, evolving into a global health burden (Larsen et al., 2023). Patients with long-term IBD face a two-to threefold increased risk of developing colorectal cancer. Although the incidence of colorectal cancer has declined in recent years, colitis-associated colorectal cancer continues to be a major cause of death among IBD patients (Shah and Itzkowitz, 2022). The mechanism of UC remains unclear. However, environmental factors, impaired microbial clearance, genetic predisposition, infections, intestinal dysbiosis, and immune dysregulation are all implicated in the pathogenesis of UC (Wu and Liu, 2023). In clinical practice, the treatment of UC primarily involves surgical intervention, nutritional support therapy, and biologic agents. However, these approaches are often associated with significant drawbacks, including high doses of corticosteroids, elevated rates of recurrence and hospitalization, a high incidence of surgical procedures, and a diminished quality of life (Wu et al., 2024). Therefore, it is imperative to conduct in-depth research into the pathogenesis of UC and to explore alternative or adjunctive therapeutic strategies for its management.

Dysfunction in immune pathways can lead to abnormal intestinal inflammatory responses, with excessive inflammation being one of the most typical characteristics of UC (Nishida et al., 2018). The balance between helper T cells 17 (Th17) and regulatory T cells (Treg) is closely related to UC. Th17 primarily secretes pro-inflammatory factors such as interleukin (IL)-6, IL-17, and tumor necrosis factor α (TNF-α), while Treg mainly secretes anti-inflammatory factors like IL-10 and transforming growth factor β (TGF-β). Under normal conditions, Th17 and Treg can convert into each other to maintain intestinal immune balance. If the Th17/Treg balance is disrupted, it can induce a massive release of pro-inflammatory factors and a reduction in anti-inflammatory factors, leading to excessive immune activity, resulting in intestinal mucosal damage and triggering UC (Ye et al., 2021). Therefore, restoring the Th17/Treg immune balance in UC patients may represent as a new target for treatment and improving patient prognosis.

The intestinal microbiome plays a vital role in maintaining host homeostasis and modulating immune responses. Dysbiosis of the gut microbiota is a significant factor contributing to inflammatory bowel disease, especially UC (Zhang et al., 2022). The gut microbiome generates a diverse array of metabolic byproducts, including short-chain fatty acids (SCFAs). SCFAs can bind to and activate PPARγ (Alex et al., 2013). It has been reported that butyrate, upon binding to PPARγ, functions as a PPARγ agonist. Consequently, the gut microbiota can suppress Th17 differentiation through the activation of PPARγ mediated by its metabolite, butyrate. Therefore, butyrate produced by gut microbiota plays a crucial role in modulating the balance between Th17 and Treg cells.

In recent years, traditional Chinese medicine (TCM) has demonstrated unique advantages in the treatment of UC, characterized by its flexibility, minimal adverse effects, and high clinical acceptability among patients (Wen et al., 2024; Zheng et al., 2022; Liu et al., 2022). Cinobufotalin is an indole alkaloid extracted from the dried skin of the toad ∗Bufo gargarizans∗, a species of the Bufonidae family. It possesses properties such as detoxification, anti-swelling, and pain relief, and exhibits a wide range of pharmacological effects, including anti-inflammatory and anti-tumor activities. Current research on cinobufotalin primarily focuses on its anti-tumor properties, such as its effects on colon cancer (Hu and Luo, 2024), liver cancer (Chen et al., 2024), and ovarian cancer (Afroze et al., 2018), while studies on its anti-inflammatory effects remain limited. Research has demonstrated that cinobufotalin significantly alleviates clinical symptoms and ameliorates intestinal mucosal damage in UC models in rats (Li et al., 2021), however, its precise mechanism of action remains poorly understood.

Mesalazine (5-ASA) is a first-line treatment for UC, with well-known anti-inflammatory, antibacterial, and immunosuppressive effects. Therefore, it was used as the positive control in this study (Peng et al., 2024). In this study, a DSS-induced UC mouse model was utilized to assess the protective effects of cinobufotalin on UC. The results demonstrated that cinobufotalin effectively mitigated the clinical symptoms of DSS-induced colitis, restored gut microbiota equilibrium, enhanced the population of SCFA-producing bacteria, decreased intestinal permeability, and regulated the Th17/Treg balance. These findings offer novel perspectives on the therapeutic potential of cinobufotalin for UC treatment.