Isolation, characterisation and determination of biological activity of coffee proanthocyanidins

Two proanthocyanidin‐containing preparations were isolated from the pulp of ripe Coffea canephora coffee cherries. The preparations were partially purified by Sephadex LH‐20 column chromatography and characterised by means of infrared and 13C NMR spectroscopy, and reactions with several functional group‐specific reagents. These proanthocyanidin‐rich extracts from coffee pulp, obtained also from coffee leaves, inhibit the germination in vitro of Hemileia vastatrix race 2 uredospores. Greater proanthocyanidin content was associated with greater potency, and the leaves of Coffea arabica, a coffee species susceptible to rust, contained less proanthocyanidins than the leaves of C canephora, a rust‐resistant coffee. © 1998 SCI.