Flavans and proanthocyanidins
The current chapter follows on from those of the three previous editions of The Flavonoids (Haslam, 1975, 1982; Porter, 1988) and will follow closely the format of the 1988 chapter. This area of flavonoid chemistry has continued to be the fastest growing, at least in terms of the number of new natural products reported in the 1986–90 period. Evidence of the increasing importance of this area of natural products chemistry has been the appearance of a number of major review articles and chapters dedicated to this topic in this period: Haslam (1989), Hemingway (1989), Hemingway and Porter (1989), Porter (1988, 1989) and Hemingway and Karchesy (1989). Together, these texts give a comprehensive review of all aspects of the chemistry and biochemistry of proanthocyanidins and their industrial significance. It is the view of the author that the researcher is now very well served for sources of basic information on the proanthocyanidins, or, to give them their traditional name, the condensed tannins.