Leucocyanidin is a colorless chemical compound that is a member of the class of natural products known as leucoanthocyanidins.

Chemistry

(+)-Leucocyanidin can be synthesized from (+)-dihydroquercetin by reduction with sodium borohydride. Molar equivalents of synthetic (2R,3S,4R or S)-leucocyanidin and (+)-catechin condense with exceptional rapidity at pH 5 under ambient conditions to give the all-trans-[4,8]- and [4,6]-bi-[(+)-catechins] (procyanidins B3, B6) the all-trans-[4,8:4,8]- and [4,8:4,6]-tri-[(+)-catechins] (procyanidin C2 and isomer).

Metabolism

Leucocyanidin oxygenase uses leucocyanidin, 2-oxoglutarate, and O2 to produce cis-dihydroquercetin, trans-dihydroquercetin (taxifolin), succinate, CO2, and H2O. Leucoanthocyanidin reductase (LAR or leucocyanidin reductase LCR) uses (2R,3S)-catechin, NADP+, and H2O to produce 2,3-trans-3,4-cis-leucocyanidin, NADPH, and H+. Its gene expression has been studied in developing grape berries and grapevine leaves. Its activity has also been measured in leaves, flowers, and seeds of the legumes Medicago sativa, Lotus japonicus, Lotus uliginosus, Hedysarum sulfurescens, and Robinia pseudoacacia. The C-4 stereochemistry of leucocyanidin substrates affects anthocyanidin synthase (ANS) products. This enzyme is an iron(II) and 2-oxoglutarate (2OG) dependent oxygenase.

Occurrence

Leucoyanidin can be found in these plants: