Figure 3. Simple Aromatic Amino Acids with Demonstrated Effects in Microbe-Host Relationship.

A growing number of simple derivatives of aromatic amino acids (inside the box) have been found to not only be produced by commensal bacteria but elicit functional responses during in vitro or in vivo biological experiments. These studies suggest that bacteria take advantage of simple enzymatic processes using abundant substrates to interact with their environment. Color of derivatives indicates matching amino acid source.