Gallocatechol or gallocatechin (GC) is a flavan-3-ol, a type of chemical compound including catechin, with the gallate residue being in an isomeric trans position.
This compound possesses two epimers. The most common, (+)-gallocatechin (GC), is found notably in green tea. The other enantiomer is called (−)-gallocatechin or ent-gallocatechin. It was first isolated from green tea by Michiyo Tsujimura in 1934.
Epigallocatechin is another type of catechin, with the gallate residue being in an isomeric cis position. It can be found in St John's wort.
In the flavonoid biosynthesis pathway in plants, (+)-gallocatechol is produced in two steps from ampelopsin via leucodelphinidin:
The two enzymes, dihydroflavonol 4-reductase and leucoanthocyanidin reductase, both use nicotinamide adenine dinucleotide phosphate as cofactors.