Therapeutic effects of epigallocatechin-3-gallate for inflammatory bowel disease: A preclinical meta-analysis

Background: Epigallocatechin-3-gallate (EGCG), the primary active compound in green tea, is recognized for its significant anti-inflammatory properties and potential pharmacological effects on inflammatory bowel disease (IBD). However, comprehensive preclinical evidence supporting the use of EGCG in treating IBD is currently insufficient. Purpose: To evaluate the efficacy of EGCG in animal models of IBD and explore potential underlying mechanisms, serving as a groundwork for future clinical investigations. Methods: A systematic review of pertinent preclinical studies published until September 1, 2023, in databases such as PubMed, Embase, Web of Science, and Cochrane Library was conducted, adhering to stringent quality criteria. The potential mechanisms via which EGCG may address IBD were summarized. STATA v16.0 was used to perform a meta -analysis to assess IBD pathology, inflammation, and indicators of oxidative stress. Additionally, dose -response analysis and machine learning models were utilized to evaluate the dose -effect relationship and determine the optimal dosage of EGCG for IBD treatment. Results: The analysis included 19 studies involving 309 animals. The findings suggest that EGCG can ameliorate IBD-related pathology in animals, with a reduction in inflammatory and oxidative stress indicators. These effects were observed through significant changes in histological scores, Disease Activity Index, Colitis Macroscopic Damage Index and colon length; a decrease in markers such as interleukin (IL)-1 beta, IL -6 and interferon-gamma; and alterations in malondialdehyde, superoxide dismutase, glutathione, and catalase levels. Subgroup analysis indicated that the oral administration route of EGCG exhibited superior efficacy over other administration routes. Dose -response analysis and machine learning outcomes highlighted an optimal EGCG dosage range of 32-62 mg/ kg/day, with an intervention duration of 4.8-13.6 days. Conclusions: EGCG exhibits positive effects on IBD, particularly when administered at the dose range of 32 - 62 mg/kg/day, primarily attributed to its ability to regulate inflammation and oxidative stress levels.