Walnut leaves from nine different cultivars (Arco, Franquette, Hartley, Lara,
Marbot, Mayette, Meylannaise, Parisienne and Rego) were studied for their phenolic
compounds. Samples were harvested along three consecutive years, at two different
geographical locations, in order to evaluate if significant differences in the phenolics
composition can be related with genetic, climatic or geographical factors. Nine compounds
(3-caffeoylquinic, 3-p-coumaroylquinic and 4-p-coumaroylquinic acids, quercetin 3-
galactoside, quercetin 3-arabinoside, quercetin 3-xyloside, quercetin 3-rhamnoside, a
quercetin 3-pentoside derivative and a kaempferol 3-pentoside derivative) were quantified
using an HPLC-DAD methodology. The qualitative profiles were identical for all samples,
but differences were observed in terms of individual compounds’ contents. Multivariate
statistical analysis was carried out, showing that significant differences exist among
production years, which can be related to climatic reasons.
