CHARACTERIZATION OF PURE PROANTHOCYANIDINS ISOLATED FROM THE HULLS OF FABA BEANS

Extraction of the hulls of faba beans with 70% aqueous acetone containing 2.8 mmol/L ascorbic acid proved to be a very efficient solvent system for the extraction of phenols. Treatment of the concentrated extract with ethyl acetate and liquefied phenol and batch adsorption on Sephadex LH-20 freed the isolated crude proanthocyanidins (PA) from small molecular weight UV-absorbing and protein contaminants. Gel filtration of the purified extract on Sephadex LH-20 yielded pure PA and showed homogeneous band during the elution at 275.2 nm (maximum). The overall yield was 12%; the preparation contained six flavan-3-ol units/molecules. © 1990, American Chemical Society. All rights reserved.