Aqueous Extract of Brassica rapa L.’s Impact on Modulating Exercise-Induced Fatigue via Gut–Muscle Axis

Exercise-induced fatigue is a common physiological response to prolonged physical activity, often associated with changes in gut microbiota and metabolic responses. This study investigates the potential role of Brassica rapa L. in modulating these responses. Using an animal model subjected to chronic exercise-induced stress, we explored the effects of Brassica rapa L. on fatigue-related biomarkers, energy metabolism genes, inflammatory responses, intestinal integrity, and gut microbiota composition. Our findings revealed that Brassica rapa L. exhibits significant antioxidant activity and effectively modulates physiological responses to fatigue. It influences gene expression related to the tricarboxylic acid (TCA) cycle in muscle tissue through the AMPK/PGC-1α/TFAM signaling pathway. Furthermore, Brassica rapa L. has been found to alleviate inflammation by inhibiting lipopolysaccharide (LPS) infection and suppressing the activation of the NF-κB pathway. It also maintains intestinal integrity and controls Gram-negative bacterial growth. A correlation analysis identified several pathogenic bacteria linked with inflammation and energy metabolism, as well as beneficial probiotic bacteria associated with improved energy metabolism and reduced inflammation. These findings underscore Brassica rapa L.’s potential for managing prolonged exercise-induced fatigue, paving the way for future therapeutic applications. The results highlight its impact on gut microbiota modulation and its role in nutrition science and sports medicine.