Indigo naturalis for inflammatory bowel disease: evidence from animal studies and molecular mechanisms.

Background: Indigo naturalis (IN) has been extensively used in prescriptions of traditional Chinese medicine to treat inflammatory bowel disease (IBD), particularly ulcerative colitis (UC). However, there is a lack of quantitative, evidence-based assessments from preclinical trials. Aims: Quantitative statistical evidence regarding the efficacy of IN in animal models of IBD remains insufficient. This study performed a meta-analysis to evaluate the therapeutic effects of IN in experiments with IBD. Methods: Relevant animal studies were identified from PubMed, Web of Science, Embase, China National Knowledge Infrastructure, SinoMed, and Wanfang databases. Two researchers independently conducted literature screening and risk-of-bias assessments using the CAMARADES 10-point quality checklist. Meta-analysis was performed using Review Manager 5.4, focusing on the histopathological index as the primary outcome measure. Results: Of the 15 eligible studies included, over half had low risks of bias in more than five items. Compared to controls, the histopathological index significantly improved after IN treatment ( Conclusion: IN demonstrated significant therapeutic efficacy in preclinical models of IBD, particularly at dosages exceeding 600 mg/kg. It protected colonic mucosal integrity and exerted beneficial effects through multiple molecular pathways.