Traditional Chinese Medicine: A promising strategy to regulate the imbalance of bacterial flora, impaired intestinal barrier and immune function attributed to ulcerative colitis through intestinal microecology

Globally, plant materials are widely used as an additional and alternative therapy for the treating of diverse diseases. Ulcerative colitis (UC) is a chronic, recurrent and nonspecific inflammation of the bowel, referred to as "modern intractable disease" according to the World Health Organization. With the continuous development of theoretical research in Traditional Chinese Medicine (TCM) and the advantages of TCM in terms of low side effects, TCM has shown great progress in the research of treating UC. This review aimed to explore the correlation between intestinal microbiota and UC, summarize research advances in TCM for treating UC, and discuss the mechanism of action of TCM remedies in regulating intestinal microbiota and repairing damaged intestinal barrier, which will provide a theoretical basis for future studies to elucidate the mechanism of TCM remedies based on gut microbiota and provide novel ideas for the clinical treatment of UC. We have collected and collated relevant articles from different scientific databases in recent years on the use of TCM in treating UC in relation to intestinal microecology. Based on the available studies, the therapeutic effects of TCM are analysed and the correlation between the pathogenesis of UC and intestinal microecology is explored. TCM is used to further protect the intestinal epithelium and tight junctions, regulate immunity and intestinal flora by regulating intestinal microecology, thereby achieving the effect of treating UC. Additionally, TCM remedies can effectively increase the abundance of beneficial bacteria that produce short-chain fatty acids, decrease the abundance of pathogenic bacteria, restore the balance of intestinal microbiota, and indirectly alleviate intestinal mucosal immune barrier dysfunction and promote the repair of damaged colorectal mucosa. Intestinal microbiota is closely related to UC pathogenesis. The alleviation of intestinal dysbiosis can be a potential novel therapeutic strategy for UC. TCM remedies can exert protective and therapeutic effects on UC through various mechanisms. Although intestinal microbiota can aid in the identification of different TCM syndromes types, further studies are needed using modern medical technology. This will improve the clinical therapeutic efficacy of TCM remedies in UC and promote the application of precision medicine.