L-theanine treatment associated with gut-brain axis and bile acid metabolism: Potential involvement of CB1 receptor

L-theanine (LTA), the characteristic proteinogenic amino acid in tea leaves ( Camellia sinensis) , exhibits biological activities such as alleviating intestinal stress and modulating nervous system functions. While existing studies have extensively explored its role in regulating systemic inflammation, the gut-brain axis mechanism of L-theanine remains poorly understood. The findings of this study suggests that L-theanine treatment is associated with systemic inflammatory responses in vivo via the gut-brain axis microbial pathway. Furthermore, using computer simulation techniques and surface plasmon resonance (SPR) technology, we identified the binding properties of L-theanine to cannabinoid receptor 1 (CB1). Innovatively, our data suggest that LTA's effects on microbiota and bile acids correlate with its potential to interact with CB1. While a direct causal link through CB1 remains to be functionally validated, these findings provide a novel hypothesis for LTA's gut-brain axis effects.