High-performance liquid chromatography and diffuse reflectance spectroscopy of flavonoids in Crataegus oxyacantha L. III--Analysis of 2-phenyl-chroman derivatives and caffeic acid.

High-performance liquid chromatographic (HPLC) and diffuse infrared reflectance spectroscopic techniques for qualitative and quantitative analysis of naturally occurring phenolic compounds in Crataegus oxyacantha L. have been applied. (+)-Catechin, (-)-epicatechin and a phenolic acid, the caffeic acid, were investigated in various extractives of Crataegus oxyacantha L. The reversed-phase chromatographic separation was achieved by a combination of isocratic and gradient elution.