Chemical Nature of Phlobaphenes

Abstract

Phlobaphenes are reddish-colored, water-insoluble phenolic substances that are believed to be related to co-occurring condensed tannins. The term is also used to describe the red insoluble material produced by treating condensed tannins with mineral acid. The chemical composition of the "natural" phlobaphenes is complex and linked to other extraneous materials in addition to condensed tannins. Phlobaphenes are variable from plant source to plant source and display a variety of functional groups not seen in the condensed tannins. Douglas-fir phlobaphenes are composed of a mixture of polymeric procyanidins, di-hydroquercetin, carbohydrate (glucosyl), and methoxyl moieties. Water insolubility appears to be due to the abundance of methoxyl groups.