Biomass photochemistry: VI—Light-induced oxidation of phlobaphene from wood

Abstract

Phlobaphene from Pinus radiata D. Don bark upon photolysis in the presence of oxygen causes a rapid bleaching. The final product from the photooxidation was isolated and analysed showing it to be an oligomer of low molecular weight with 3·5±0·5 carboxylic acid units per catechin unit. The same product was obtained from photolysis of catechin under the same conditions. Phlobaphene showed excellent sensitizer properties using guanosine as a singlet oxygen detector.