Polyphenols and antioxidant capacity of Sorbus domestica L. fruits

Polyphenols from astringent fruits of the service tree Sorbus domestica L. were isolated and quantified by combining extraction methods with column chromatography on Sephadex LH-20 and reversed-phase HPLC with UV-detection and post column derivatisation. The contents of hydroxycinnamic acids, flavonols, monomeric flavanols, oligomeric and polymeric proanthocyanidins were estimated. Representative polyphenolic fractions were tested for their antioxidant capacity with the xanthine/xanthine oxidase model. The oligomeric proanthocyanidins showed highest activity followed by the hydroxycinnamic acid fraction and the polymers.