Roudoukou–Suanzaoren Ameliorates Chronic Restraint-Induced Anxiety- and Depression-Like Behaviors in Mice via the Gut–Brain Axis

Anxiety and depression are growing global burdens with limited drug options. Traditional Chinese medicine (TCM) offers unique advantages, including Roudoukou-Suanzaoren (RS), an ancient TCM-derived beverage with the potential for treating these conditions. This study aims to explore whether this combination improves the outcomes. The results show that the main constituents of RS include flavonoids, terpenoids, alkaloids, and phenylpropanoids. Behavioral and histopathological analyses demonstrate that RS alleviates chronic restraint stress (CRS)-induced anxiety- and depression-like behaviors and attenuates neuropathological damage in relevant brain regions; the underlying mechanism is likely mediated by the CREB/BDNF/TrkB signaling pathway. Meanwhile, RS reduces proinflammatory cytokines in tissues, decreases hippocampal microglial numbers, and increases astrocytes. Additionally, RS attenuates colonic injury, restores intestinal permeability, upregulates tight-junction proteins, and improves gut microbiota dysbiosis. This study highlights that RS exerts antianxiety and antidepression effects by modulating the gut microbiota, controlling inflammatory responses, and increasing BDNF levels through the "gut-brain axis" pathway.