Natural products regulate gut microbiota and SCFA metabolism in IBD: mechanisms and therapeutic potential

Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), is a chronic relapsing inflammatory condition of the gastrointestinal tract. Over the past few decades, the global incidence of this disease has continued to rise, imposing a heavy socioeconomic burden. IBD is typically characterized by gut microbiota dysbiosis and reduced short-chain fatty acids (SCFAs) levels, which in turn lead to impaired intestinal barrier function and decreased immune tolerance. Multiple studies have shown that natural products, including polysaccharides, polyphenols, alkaloids, and terpenoids, can modulate the gut microbiota in IBD, with changes in SCFA concentrations observed in some preclinical studies. These effects have been associated with alterations in bacterial taxa such as Faecalibacterium prausnitzii, Bifidobacterium, and Christensenella minuta. These findings suggest that natural products may regulate the gut microbiota-SCFA metabolic axis; however, the direct causal relationships among changes in microbial composition, SCFA concentrations, and anti-inflammatory effects remain to be established. This review summarizes current mechanisms and translational opportunities for natural products targeting the microbiota-SCFA axis in IBD.