Antioxidant activity and phenolic composition of Corylus colurna.

Corylus colurna L. (Turkish hazel), a common hazel species in Europe, could be considered as a source of pharmacologically important natural compounds, since other members of the Corylus genus have been reported to contain several constituents with beneficial biological activity. Nevertheless, its phytochemical exploration is still incomplete. In this study the potent antioxidant phenolic compounds in different parts of the plant were investigated. The phenolics in the leaves, bark, catkins and involucre of C. colurna possess notable scavenger activity on both DPPH and ABTS free radicals. The total polyphenol content shows significant correlation with the antioxidant activity of the samples. Twenty-three phenolic compounds - hydroxycinnamic acid derivatives, flavonoid derivatives and diarylheptanoids - were characterized in the C. colurna extracts by LC-DAD, LC-ESI-TOF and LC-ESI-QQQ-MS.