Biology Reference
In-Depth Information
Chapter 3
Biosynthesis of Ellagitannins: Old Ideas and
New Solutions
Georg G. Gross
*
Molekulare Botanik, Universität Ulm, 89069 Ulm, Germany. *Retired;
private address: Kirchstrasse 2, 88480 Achstetten, Germany;
gg.gross@t-online.de
3.1 Introduction
Plants have always been an indispensable part of human life, not only as
important nutrients, but also as a source of valuable chemicals for
manifold applications in medicine, flavoring, painting or technology. In
contrast to alkaloids or essential oils, the role of plant phenolics, which
certainly represent the most abundant class of natural plant products, has
been widely ignored. This statement applies particularly to tannins,
i.e.
,
plant polyphenols that have been used by mankind over many thousand
years for the production of leather from raw animal hides. It was only at
the beginning of the 20
th
century that intensive chemical studies on the
nature of such substances were conducted, particularly by E. Fischer, K.
Freudenberg and P. Karrer, just to mention a few prominent names.
Some principal structural features of hydrolyzable tannins from sumac
(Chinese gallotannin) and oak (Turkish gallotannin) were discovered in
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