HPLC-DPPH Screening Method for Evaluation of Antioxidant Compounds in Corylus Species

Corylus avellana L., C. colurna L. and C. maxima Mill. have been used in traditional medicine for a long time for the treatment of various diseases, such as phlebitis, varicose veins, haemorrhoidal symptoms and eczema. Our previous studies indicated the presence of flavonol-3-O-glycosides, diarylheptanoids and caffeic acid derivatives in the bark and leaf extracts of the three species mentioned above. Comparison of in vitro DPPH scavenging activity of the Corylus extracts prepared with ethyl acetate and methanol to those of well-known antioxidant phenolics was performed. The contribution of certain compounds to the total antioxidant activity of the extracts was investigated by developing a HPLC method coupled to the DPPH radical scavenging assay.