Characterization of phenolic compounds in Chinese hawthorn (Crataegus pinnatifida Bge. var. major) fruit by high performance liquid chromatography–electrospray ionization mass spectrometry

Hawthorn (Crataegus spp.) fruits are increasingly popular as raw materials for nutraceuticals and functional foods. As a major group of bio-active components of hawthorn, the phenolic compounds of the fruits have not been well characterized so far. After extraction with 80% aqueous ethanol, the phenolics of the fruits of a major Chinese hawthorn variety, Crataegus pinnatifida Bge. var. major, were separated by polyamide column chromatography, followed by analyses by high performance liquid chromatography combined with diode array UV spectrometry and electrospray ionization mass spectrometry. Ideain (cyanidin-3-O-galactoside), chlorogenic acid, procyanidin B2 [epicatechin-(4β → 8)-epicatechin], epicatechin, hyperoside (quercetin-3-O-galactoside) and isoquercitrin (quercetin-3-O-glucoside) were identified with UV spectra, mass spectra and reference compounds. In addition, 35 compounds were tentatively identified based on UV and mass spectra. These compounds were mostly B-type procyanidins (PA) and their glycosides including aglycons of 3 dimers, 3 trimers, 8 tetramers, 4 pentamers, 2 hexamers and 2 glycosides of PA monomers, 7 glycosides of PA dimers, 1 glycoside of a PA trimer, 2 glycosides of PA tetramers, 1 glycoside of a PA pentamer, and 2 glycosides of quercetin. This is the first systematic study of phenolic compounds in Chinese hawthorn fruits and the first report of the presence of glycosylated procyanidins in hawthorn.