As a traditional Chinese medicine, Sanao decoction (SAD) has been used to treat chronic obstructive pulmonary disease (COPD) for multi-years. However, the potential mechanism and targets for its effects of SAD remain unknown. The 94 components of SAD were identified by UPLC–LTQ–Orbitrap MS. Meanwhile, the quantitative analysis of multi-components by single marker (QAMS) method was used to control the quality of SAD, including ephedrine hydrochloride, amygdalin, liquiritin, liquiritigenin, glycyrrhizic acid and glycyrrhetinic acid. The method was strictly validated with recovery (90.0–110.0%), precision [relative standard deviation (RSD), 0.79–2.01%], stability (RSD, 1.84–2.64%), repeatability (RSD, 0.45–3.03%) and relative correction factors (RSD, 0.28–2.67%), respectively. All the compounds showed good linearities (R2 > 0.999). Subsequently, 37 target proteins of SAD in the treatment of COPD were screened. The “Compounds-Targets” interaction and protein–protein interaction network found that TNF-α, IL-6 and VEGFA may act a crucial role in the treatment of COPD by SAD. Molecular docking demonstrated that TNF-α had good affinity with the main components of SAD. A strategy of QAMS and network pharmacology was a novel method to assess the quality control of SAD and uncover the targets and potential mechanism of SAD in the treatment of COPD.

Gut microbiota research in inflammatory bowel disease (IBD) is transitioning from holistic community-level associations toward causal validation of individual bacteria and their metabolites. However, existing causal evidence is dispersed across diverse pathways and experimental models, lacking systematic integration and comparative assessment of evidence strength. Building on the concept of grading causal evidence in microbiome studies, we extend this approach into a five-tier progressive validation framework that covers the entire causal chain—from initial association discovery to the identification of specific effector metabolites. Using this framework, we systematically collate the single-bacterium–metabolite–host target axes that have been validated by high-level experimental methods. Focusing on four major pathways—AhR/tryptophan metabolism, bile acid/nuclear receptor signaling, short-chain fatty acid/vitamin/energy metabolism, and cell death-related pathogenic mechanisms—we integrate the molecular mechanisms through which specific bacteria and their causally linked metabolites regulate intestinal barrier integrity, immune responses, and inflammation resolution. We further discuss the modulatory influences of host genetics, diet, and medications on these axes, as well as therapeutic strategies such as live bacterial preparations, engineered probiotics, and postbiotics. Causal studies on individual bacteria and metabolites in IBD have progressed from isolated mechanistic discoveries towards systematic consolidation. It should be acknowledged, however, that most of the high-level evidence summarized in this review derives from animal models and preclinical studies, whereas robust human validation remains limited. In addition, protective mechanisms appear to considerably outnumber pathogenic ones, suggesting a marked imbalance in the current evidence base. To bridge the gap between mechanistic validation and clinical application, future research should focus on validating causal chains from animal models in well-designed human cohorts, exploring pathogenic mechanisms that drive disease onset, and clarifying interactions among different metabolites. By synthesizing available evidence, identifying key research gaps, and acknowledging translational limitations, this review aims to provide a foundational reference for researchers, while recognizing that further translational efforts are needed to move these preclinical findings toward clinical application.

Ethnopharmacological relevance: Glycyrrhiza glabra L. (licorice) is a widely used medicinal plant in traditional Chinese medicine, where it has long been applied for the treatment of gastrointestinal inflammatory conditions such as abdominal pain, diarrhea, and dysentery. Glycyrrhizic acid (GA) is its primary bioactive constituent and has been traditionally used for inflammatory and ulcerative disorders, including gastritis, peptic ulcers, and inflammatory bowel disease. Despite its long-standing ethnomedicinal use, the pharmacological mechanism by which GA alleviates ulcerative colitis (UC), particularly its role in ferroptosis regulation and gut microbiota-associated lipid metabolism, remains poorly defined. This study aims to provide a modern pharmacological basis for the traditional use of Glycyrrhiza glabra in UC treatment.Aim of the study: This study aimed to investigate whether GA alleviates UC by regulating ACSL4/GPX4-mediated ferroptosis. A secondary objective was to determine whether this effect is accompanied by gut microbiota-associated remodeling of linoleic acid (LA) and arachidonic acid (AA) metabolism.Materials and methods: A dextran sulfate sodium (DSS)-induced UC mouse model was established. GA was administered at 25, 50, and 100 mg/kg by oral gavage. 16S rRNA sequencing, untargeted metabolomics, untargeted lipidomics, and multi-omics integration were performed to profile gut microbiota and lipid metabolic changes. Fecal microbiota transplantation (FMT) was conducted to evaluate the contribution of GA-shaped microbiota. The direct binding of GA to ACSL4 and GPX4 was assessed by molecular docking, CETSA, DARTS, and SPR. In vitro, TNF-α-stimulated Caco-2 cells were used to validate the effects of GA on ferroptosis and intestinal barrier function.Results: In DSS-induced UC, ferroptosis was increased in colonic tissues, as evidenced by GPX4 downregulation and elevated lipid peroxidation. GA showed direct binding to ACSL4 and binding/stabilizing evidence for GPX4. GA treatment was associated with reduced pro-ferroptotic phospholipid remodeling and enhanced lipid peroxide detoxification, possibly through its interaction with ACSL4/GPX4. In parallel, GA treatment remodeled the gut microbiota, particularly by suppressing Pseudomonas overgrowth, and reduced LA–AA metabolic levels. FMT using feces collected from GA treated donors ameliorated UC phenotypes and mitigated ferroptosis in recipient mice, suggesting that GA reshaped microbiota is at least partially involved in these beneficial effects. Importantly, our in vitro cellular experiments further demonstrated the microbiota independent protective actions of GA toward intestinal epithelial cells.Conclusion: GA alleviated UC at least in part through mechanisms involving direct binding to ACSL4/GPX4 and repression of ferroptosis, accompanied by gut microbiota remodeling and decreased LA–AA metabolic levels that may further contribute to mucosal protection. These preclinical findings support GA as a ferroptosis-targeting candidate for UC; however, functional causality and pharmacokinetic exposure remain to be established.