Chemical ecology of tannins: recent developments in tannin chemistry reveal new structures and structure-activity patterns.

Tannins are chemically complex plant polyphenols and only little is known of their true molecule-specific anti-herbivore activities. Here we will show that modern tannin chemistry is able to reveal fully new types of tannins in plants together with new types of biological activities for the tannins. Most of these new findings relate to ellagitannins, one of the least studied and underestimated classes of bioactive plant polyphenols.