Indigo alkaloids, such as indigo, indirubin and its derivatives, have been identified as effective antiviral compounds in Baphicacanthus cusia. Evidence suggests that the biosynthesis of indigo alkaloids in plants occurs via the shikimate pathway | Molecular cloning and metabolomic characterization of the 5- enolpyruvylshikimate-3-phosphate synthase gene from Baphicacanthus cusia