Hazelnut tree leaf

Five soluble phenolic acids (free and esterifled), one of which is a hydroxylated derivative of benzoic acid (gallic acid) and four are cinnamic acid derivatives (caffeic, p-coumaric, ferulic, and sinapic acids), have been studied and tentatively identified in ethanolic extracts of hazelnut kernel and hazelnut by-products (Table 13.2) [31]. The order of total phenolic acid concentration was as follows hazelnut hard shell > hazelnut green leafy cover > hazelnut tree leaf > hazelnut skin > hazelnut kernel. Different phenolic acids predominate in each plant part examined. Among the identified phenolic acids, p-conmaric acid was most abundant in hazelnut kernel, hazelnut green leafy cover, and hazelnut tree leaf, whereas gallic acid was most abundant in hazelnut skin and hazelnut hard shell, possibly implying the presence and perhaps the dominance of tannins in the latter samples (Table 13.2). The same number, but different concentration, of phenolic acids have also been reported in hazelnnt kernel and hazelnut green leafy cover [30]. 

Recently, Shahidi et al. [31] found that total antioxidant activity of hazelnut extracts ranged from 29 to 148 xmol TE/g of ethanolic extract, with lowest activity in hazelnut kernel aud highest in hazelnut tree leaf (Table 13.1). The total antioxidaut activity of hazelnut by-product extracts were approximately 4-to5-fold higher than that of hazelnut kernel at the same extract concentration. At a given concentration, hazelnut by-product extracts would serve as a more effective antioxidant than hazelnut kernel extract. Consideration of defatted hazelnut (on an extract basis) and hazelnut (as is weight basis) make the quantitative comparison between the studies of Wu et al. [4] and Shahidi et al. [31] impossible. 

Hazelnut green leafy cover Hazelnut tree leaf... 

Small amounts of paclitaxel were also isolated from Turkish Tombul hazelnut tree leaf (0.05 J.g/g extract) and hard shell (0.08(tg/g extract). In addition to paclitaxel, 10 deacetyl baccatin III and cephalomannine (leaf and hard shell) and baccatin III (green leafy cover) were found in the extracts (Table 13.10). Taxanes were not detected in the extracts of hazelnut kernel and hazelnut skin from Turkish Tombul cultivar. 

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