Essential Oil Volatile Fingerprint Differentiates Croatian cv. Oblica from Other Olea europaea L. Cultivars

Abstract

Olive leaves are a highly available by-product from table olive and olive oil production. They are nowadays strongly valuable for their major bioactive compounds and their beneficial effects. To determine the differences between two Croatian domestic (Lastovka, Oblica) and two introduced (Leccino, Frantoio) cultivars, physical and chemical analysis of olive leaves were performed: surface area, color variability, total phenolic amounts, and essential oil volatile profiles were analyzed at three harvest periods. All cultivars greatly differed in surface area, with cv. Lastovka being the smallest. Color variability resulted in an overall decrease in darkness and amounts of green and yellow that could be attributed to a decrease in photosynthetic demand and chlorophyll content. The highest amount of total phenolic content occurred in the summer months, followed by a reduction until October. Essential oils volatiles were determined by GC-MS and showed great diversity not only amongst cultivars but also between harvest periods, with overall 45 compounds identified. Principal component analysis distinguished domestic cultivar Oblica from the other observed cultivars, mainly due to its essential oil volatile fingerprint. Compounds that differentiated cv. Oblica were aldehydes ((E,Z)-2,4-heptadienal, (E,E)-2,4-heptadienal, decanal), ketones ((E)-β-damascone, dihydrodehydro-β-ionone), sesquiterpenes (cyclosativene, α-copaene, α-muurolene) and saturated hydrocarbons (tetradecane, hexadecane). Essential oil volatile fingerprint attributed the highest to the biodiversity of domestic cv. Oblica through all three harvest periods.

Biophenolic Profile Modulations in Olive Tissues as Affected by Manganese Nutrition

“…Nutrient solutions were renewed on a biweekly basis. Overaccumulation of salts in the substrate was avoided by applying 500 mL of tap water once per month [ 64 ].…”

“…Biophenols were extracted as previously described [ 64 ] with some minor modifications. Oven-dried and finely ground olive roots (750 mg), stems (500 mg), and leaves (500 mg) were separately extracted with 20 mL of methanol 80% ( v / v ) in an ultrasonic bath (Sonorex Digitec; Bandelin electronic, Berlin, Germany) for 20 min.…”

Antioxidant Capacity of Free Volatile Compounds from Olea europaea L. cv. Oblica Leaves Depending on the Vegetation Stage

“…The (E)-β- damascenone was a one of major compound in Croatian cv. Oblica from period August, September and October [ 6 ] so it can be concluded that this compound is synthesized throughout the year.…”

“…europaea [ 4 ]. The area under olive cultivation in Croatia is very large and the most important variety is “Oblica”, which is the subject of the present study [ 5 , 6 ].…”

“…europaea of Croatian cultivars: Oblica, Lastovka, Leccino and Frantoio were investigated in the period of August, September and October. The results showed that Oblica cultivar EO was abundant in aldehydes, ketones and sesquiterpenes [ 6 ]. Despite the numerous biological effects of polyphenols contained in olive leaves, the hydrosols obtained from olive leaves have never been phytochemically analyzed, and we hypothesize that these harmless water extracts may be a readily available source of biologically active substances with antioxidant capacity.…”