Effect of Geographical Location on the Phenolic and Mineral Composition of Chetoui Olive Leaves
Mariem Zakraoui, Hédia Hannachi, Igor Pasković, Nikolina Vidović, Marija Polić Pasković, Igor Palčić, Nikola Major, Smiljana Goreta Ban, Lamia Hamrounı
Abstract
In this study, we investigated the influence of pedological parameters and variation of altitude on the mineral nutrients, phenolic compounds, and antioxidant activities of olive leaves. Samples of the Chetoui cultivar were collected from eight geographical locations with different altitudes. Levels of phenolic compounds varied according to the altitude. Classification of the locations revealed that altitude 1 (>500 m) was characterized by high levels of secoiridoids and simple phenols, while altitude 2 (500–300 m) and altitude 3 (<300 m) were higher in flavonoids. Levels of Mn, Ca and B in the leaves and level of Zn in the soil were significantly correlated with the abundance of oleuropein and luteolin-7-O glucoside, the most important phenols in Chetoui olive leaves. The results suggest that, in addition to pedological criteria, environmental conditions also influence the formation of phenolic compounds.