Fig. 10 in Stilbenes: Source plants, chemistry, biosynthesis, pharmacology, application and problems related to their clinical Application-A comprehensive review

Fig. 10. Biosynthesis pathway of stilbenes in plants: Phenylalanine and tyrosine amino acids are produced through the shikimate pathway. Both amino acids are converted to cinnamic acid and coumaric acid using phenylalanine ammonia-lyase (PAL) and tyrosine ammonia-lyase (TAL). Both acids are changed to their respective CoA products using the CoA ligase enzyme. Cinnamyl-CoA and coumaroyl-CoA are then converted to the monomeric stilbenes pinosylvin and resveratrol using stilbene synthase (STS). Both stilbenes are used as the precursors of several types of stilbenes by modifications such as methylation, hydroxylation, glycosylation, isomerization, and oligomerization. Using similar enzymes, caffeic acid is also used as the precursor of piceatannol, an additional monomeric origin of some stilbenes. Cinnamic acid can also be converted to coumaric using coumarate-4-hydroxylase, giving resveratrol through coumaroyl-CoA. Optionally, HpaBC is used to convert resveratrol to piceatannol.