Identification of a flavonoid 7-O-glucosyltransferase from Andrographis paniculata

Andrographis paniculata is an important traditional medicinal herb in which flavonoids are part of the primary specialized metabolites. A flavonoid glucosyltransferase with broad substrate spectrum (named ApUGT3) was successfully identified by screening homologous glycosyltransferase genes from A. paniculata. The enzyme displayed glycosylation activity toward multiple flavonoids in vitro, and the major products were identified as 7-O-glucosides. Phylogenetic analysis revealed that ApUGT3 is the first reported glycosyltransferase from the Acanthaceae family that belongs to cluster I, suggesting that ApUGT3 is a new flavonoid glycosyltransferase of this subcluster. This enzyme is potentially useful as powerful glycosylation catalysts to modify flavonoid-like compounds and improve their biological activities.