Vegetable tannins - lessons of a phytochemical lifetime.

After the early encouragement from the outstanding contribution in the early 1900s of Emil Fischer to an understanding of vegetable tannins the work of the following half-century had simply exemplified the complexity of the problems they presented. It was generally recognised [Freudenberg, 1920. Die Chemie der Natürliche Gerbstoffe. Springer, Berlin] that there was a broad division into condensed or non-hydrolysable and hydrolysable tannins but much else remained vague and untidy. In the 1950s Bate-Smith and Swain gave the lead into totally new ways of looking at these substances. They drew aside for the first time the curtains on the botanical aspects of these substances to reveal the rich vistas which lay beyond. It was to initiate remarkable progress in the next fifty years in the understanding of their chemistry and biochemistry; some of the principal developments of this work are reviewed herein.