Traditional Chinese Medicine Ameliorates Depression via the Gut-Brain Axis: A Review Focus on NLRP3/TLR4-Mediated...

Depression, a global mental disorder, is linked to gut-brain axis (GBA) dysfunction. This review explores how traditional Chinese medicine (TCM)-including single herbs (eg, Astragalus membranaceus, Lycium barbarum), herbal formulas (eg, Xiaoyaosan, Xiaochaihu Decoction), and acupuncture-alleviates depression via the GBA, focusing on neuroscience-relevant mechanisms (inflammation, neurotrophy).

A systematic literature search was conducted on PubMed, China National Knowledge Infrastructure (CNKI), and Embase from database inception to July 2025. Keywords included ["Traditional Chinese Medicine" or "TCM" or "herb" or "herbal extracts" or "Chinese herbal formulas"], ["depression" or "Depressive like behavior"], ["immune regulation"], ["inflammatory reaction"], ["neuroregeneration" or "nerve" or "neurotransmitter"]. Including peer-reviewed studies on human/animal models, articles that do not meet the requirements are excluded. A total of 307 eligible studies were included.

TCM regulates gut microbiota composition-eg, increasing Lactobacillus and Bifidobacterium while reducing pathogenic taxa. Mechanistically, TCM inhibits pro-inflammatory pathways: herbs (eg, Astragalus membranaceus) and formulas (eg, Xiaoyaosan) downregulate IL-6, TNF-α, and IL-1β via suppressing NLRP3 inflammasome and TLR4/NF-κB signaling. They also enhance anti-inflammatory IL-10, elevate neurotransmitters (5-HT, DA), and upregulate BDNF. Acupuncture mirrors these effects, reducing plasma IL-6/TNF-α and restoring microbial balance to improve depressive behaviors.

TCM alleviates depression by integrating gut microbiota modulation, inflammatory suppression, and neuroprotection through the GBA. This review highlights TCM's potential as a safe, alternative therapy for depression and identifies directions for standardized, large-scale clinical validation.