BIOSYNTHESIS OF CYANIDIN IN BUCKWHEAT HYPOCOTYLS

Aminooxyacetate (AOA), an inhibitor of phenylalanine transamination and deamination in vitro, inhibits the light-induced formation of chlorogenic acid, leucoanthocyanin, rutin and anthocyanin (cyanidin glycosides) in buckwheat hypocotyls. Anthocyanin production is inhibited 87 ± 4%, when excised hypocotyls are incubated in 0.5 mM AOA in Petri dishes. AOA is also effective when taken up through the roots or sprayed onto seedlings. In the presence of biosynthetic precursors of cyanidin (l-phenylalanine, trans-cinnamic acid, p-coumaric acid, naringenin, eriodictyol, dihydrokaempferol. and dihydroquercetin) the inhibition of anthocyanin formation caused by AOA is completely or partially reversed. The general applicability of a complementation technique involving AOA or a similar inhibitor of phenylpropane synthesis is proposed to investigate the biosynthesis of natural products derived from cinnamic acid. © 1979.