The origins of tannins and flavonoids in black-wattle barks and heartwoods, and their associated ‘non-tannin’ components

Abstract

1. The distributions of flavonoid, carbohydrate, amino acid and imino acid components in the leaves, twig bark, stem bark, root bark and heartwoods of the black-wattle tree were compared by paper chromatography after their isolation from specific portions of the tree. 2. Wattle leaves contain mainly myricitrin, (+)-gallocatechin, an unknown myricetin glycoside and leuco-delphinidin tannins, together with smaller amounts of (+)-catechin, quercitrin and other flavonol glycosides. These are prominent in the twig bark, but decline progressively with age in the stem bark and are absent from root bark. 3. The non-phenolic components of the mature stem bark were shown to be (+)-pinitol, sucrose, glucose, fructose, l(-)-pipecolic acid, trans-4-hydroxy-l(-)-pipecolic acid, alpha-alanine, arginine, aspartic acid, glutamic acid, l(-)-proline, serine, a ;steroid' alcohol and a long-chain beta-diketone. 4. Wattle bark and heartwood ;tannins' consist of the analogues of closely related prototypes with common origins in the vascular tissues of the bark. Leaf ;tannins' are superimposed on the bark components mainly during the initial stages of bark growth. 5. Origins of the pipecolic acids and the transformations of carbohydrates in the sap- and heart-woods are discussed.