HPLC method for screening of flavonoids and phenolic acids in berries

Abstract

An HPLC method is described for the simultaneous detection of selected flavonoids (kaempferol, quercetin, myricetin) and phenolic acids (p-coumaric, caffeic, ferulic, p-hydroxybenzoic, gallic and ellagic acids) in berries. Three extraction and hydrolysis methods and three HPLC column and solvent systems were tested for strawberry and blackcurrant. The optimal extraction and hydrolysis of these phenolics was obtained by incubating freeze-dried berry samples for 16 h at 35°C in 50% methanol and 1·2 M HCl. The best separation of the hydrolysed phenolics was achieved in ODS-Hypersil column using a ternary solvent system (dihydrogen ammonium phosphate, orthophosphoric acid and acetonitrile) with increasing hydrophobicity and changing pH. The method was used for the determination of the phenolic profiles of strawberry and blackcurrant. The relative content of flavonoids was low in strawberry but over 50% in blackcurrant. Ellagic acid was the main phenolic in strawberry while its relative content was very low in blackcurrant. Although the precision of the method was not equally good for all the phenolics, a reasonable amount of information was obtained within a single analysis. This simple, semiquantitative method is suitable for routine screening of the major phenolics in berries. © 1998 SCI.