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.