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Phytochemical Farming: Mineral Nutrients and Elicitors Application to Enhance Olive Leaf Phenolics

ABOUT THE PROJECT

Olive (Olea europaea L.) is among the most important crops, particularly fruit ones, grown in the Mediterranean area. Olive tree is used for its fruits (oil), leaves, wood, and all parts have important role in the Mediterranean diet and way of life. In addition to its role in diet or history, olive has an important economic role in the area.

Olive leaves have been always linked with folk medicine remedies. Oleuropein and hydroxytyrosol are considered the main active olive compounds and their health benefits thought their anti-carcinogenic, anti-inflammatory, and antimicrobial proprieties has been proven. Nevertheless, oleuropein and hydroxytyrosol as well as total phenols, have specific role plant protection and resistance against fungal pathogens which may be of crucial importance for sustainable olive growing. In general, it has been noticed that phenolic and polyphenolic compounds, as pre-formed antibiotic compounds, are ubiquitous in plants and play an important role in host plant’s pre-existing chemical defences against filamentous fungi. The phenolics in olive leaves, beside upgraded resistance to fungal pathogens, may have potential in the production of functional food and nutraceuticals. They could be easily used as oral remedies in the treatment of stomatognatic pathological conditions, where the need of finding new therapeutic procedures has led to increased interest in the use of natural substrates.

There are evidence that agricultural practices can increase phenolics in olive leaves. Only a few studies have been focused on studying the effects of olive mineral nutrition on the olive leaves phenolic profile. In this project, series of experiments are planned to be conducted in order to determine the effect of selected mineral elements and elicitors on leaf phenolic profile of olive cultivars. The effect of previously selected mineral/elicitor treatment as the best phenolic enhancer, on the development of olive leaf spot (Venturia oleaginea – syn. Spilocaea oleaginea), will be tested under greenhouse and field conditions. The impact of best phenolic enhancer will be tested thought quality of olive oil on Leccino cultivar grown at different terroirs. The preclinical and clinical studies investigating the effect of olive leaf extract on oral cavity candidiasis will be conducted during this project as well.

In this multidisciplinary project, agricultural, chemical and medicinal researches are joined together to explore the role of selected plant nutrients in changes of phenolic profile. Effect of changes in phenolic profile on resistance to fungal diseases and olive leaves application in stomatology will be part of the project as well.  

· Project title: Phytochemical Farming: Mineral Nutrients and Elicitors Application to Enhance Olive Leaf Phenolics;  UIP-2017-05-8464 PhytoFarmOL

· Project leader: dr.sc. Igor Pasković, Institute of Agriculture and Tourism (IPTPO), Karla Huguesa 8, 52440 Poreč (E-mail: paskovic@iptpo.hr)

· Project financed by: Croatian Science Foundation

· Partner Institutions:
Teaching Institute of Public Health Primorsko-Goranska County (ZZJZPGŽ)

University of Zagreb Faculty of Agriculture (AGRZG)

Medical Faculty, Rijeka University (MEDRI)

· Project duration: 01/12/2017 – 30/11/2022

· Project value: 270.000,00 €

NEWS

The main hydroponic trial was set up in a greenhouse 

During October and November 2018 a hydroponic trial was set up in the greenhouse of the Institute of Agriculture and Tourism. Istrian Bjelica plantlets were potted in plastic pots into a supstrate made by a mixture of quartz sand and perlite (1:1). After the set up of the trial, nutrient solutions were prepared with the modulation of six different concentrations based on seven nutrients (N, Ca, Mg, Mn, Zn, Cu i B) i compared with a standard Hoagland solution as a control treatment. The aim of the trial iz to establish the effect of different nutrient solutions contentrations of N, Ca, Mg, Mn, Zn, Cu and B on the composition of phenolics in olive leaves.

October-November 2018

Statistical analysis of the phenolic and mineral composition of the collected olive leaves was carried out

Graphical representation of PLS analysis of phenolic and mineral composition of olive leaves.

15/07/2018

Set-up of additional preliminary hydroponic trial

In July 2018 a preliminary hydroponic experiment was set up at the Institute of Agriculture and Tourism. The experiment was set up testing three treatments where the influence of the application of different boron (B) concentrations and its influence on olive leaf phenolic and mineral composition was investigated.

 

13/07/2018

The phenolic and mineral composition of the collected samples was determined

In the period from April till June 2018 at the Institute of Agriculture and Tourism and Teaching Institute of Public Health Primorsko-Goranska County olive leaves samples collected across Croatia were prepared and analyzed. The phenolic and mineral composition of the most important native olive cultivars was determined.

April-June 2018

Spring sampling of different olive cultivars across Croatia
Location Cultivar
Vodnjan
Leccino, Istarska bjelica, Buža ženska, Karbonaca, Oblica
Poreč
Leccino, Istarska bjelica, Buža ženska, Buža muška, Buža puntoža, Karbonaca, Rosinjola, Črnica, Moražola, Bova
Krk
Leccino, Istarska bjelica, Rosinjola, Oblica, Levantinka, Plominka, Drobnica
Pag
Leccino, Istarska bjelica, Oblica, Levantinka, Drobnica, Lastovka
Zadar
Leccino, Istarska bjelica, Buža, Oblica, Levantinka, Drobnica, Lastovka
Split
Leccino, Oblica, Levantinka, Lastovka, Drobnica, Mastrinka

22/03/2018

Chemical analysis of additional preliminary foliar experiment

In the fall of 2017, an additional preliminary study was carried out to determine the influence of foliarly applied microelements on mineral composition and bioactive components in olive leaf. Furthermore, olive leaf infusions were prepared and volatile compounds and aromas were determined.

15/03/2018

Winter sampling of different olive cultivars across Croatia
Location Cultivar
Vodnjan
Leccino, Istarska bjelica, Buža ženska, Karbonaca, Oblica
Poreč
Leccino, Istarska bjelica, Buža ženska, Buža muška, Buža puntoža, Karbonaca, Rosinjola, Črnica, Moražola, Bova
Krk
Leccino, Istarska bjelica, Rosinjola, Oblica, Levantinka, Plominka, Drobnica
Pag
Leccino, Istarska bjelica, Oblica, Levantinka, Drobnica, Lastovka
Zadar
Leccino, Istarska bjelica, Buža, Oblica, Levantinka, Drobnica, Lastovka
Split
Leccino, Oblica, Levantinka, Lastovka, Drobnica, Mastrinka

20/01/2018

Autumn sampling of different olive cultivars across Croatia
Location Cultivar
Vodnjan
Leccino, Istarska bjelica, Buža ženska, Karbonaca, Oblica
Poreč
Leccino, Istarska bjelica, Buža ženska, Buža muška, Buža puntoža, Karbonaca, Rosinjola, Črnica, Moražola, Bova
Krk
Leccino, Istarska bjelica, Rosinjola, Oblica, Levantinka, Plominka, Drobnica
Pag
Leccino, Istarska bjelica, Oblica, Levantinka, Drobnica, Lastovka
Zadar
Leccino, Istarska bjelica, Buža, Oblica, Levantinka, Drobnica, Lastovka
Split
Leccino, Oblica, Levantinka, Lastovka, Drobnica, Mastrinka
Metković
Leccino, Istarska bjelica, Oblica, Levantinka, Lastovka, Drobnica, Istarska crnica

01/12/2017

PROJECT OBJECTIVES

OBJECTIVE 1: Installation of the research group

OBJECTIVE 2: to determine olive leaf phenolic and mineral profile of the most important Croatian olive cultivars and compare it to Leccino cultivar as most widespread allochthonous cultivar in Croatian orchards.

OBJECTIVE 3: to determine impact of different levels elements in nutrient solution on olive plantlets leaf phenolic profile under controlled conditions

OBJECTIVE 4: to determine impact of different plant elicitors and selected plant nutrients applied foliarly on olive plantlets leaf phenolic profile under controlled conditions

OBJECTIVE 5: to define foliar application protocol for enhancing olive leaf phenolics

OBJECTIVE 6: to determine effect of selected plant nutrient or elicitor on olive plantlets resistance to fungal pathogen Venturia oleaginea (syn. Spilocaea oleaginea).

OBJECTIVE 7: to determine the effect of foliar application protocol on leaf and oil phenolic profile under field conditions

OBJECTIVE 8: to conduct series of in vitro and clinical experiments to determine the effects of olive leaf extracts on oral candidiasis

OBJECTIVE 9: to apply project(s) of new research group to competitive research grant(s)

PROJECT TEAM

dr.sc. Igor Pasković, IPTPO

PROJECT LEADER

mr.sc. Paula Žurga, ZZJZPGŽ

PROJECT COLLABORATOR

doc.dr.sc. Joško Kaliterna, AGRZG

PROJECT COLLABORATOR

doc.dr.sc. Sunčana Simonić-Kocijan, MEDRI

PROJECT COLLABORATOR

Jana Klanjac, mag.ing.agr., IPTPO

PROJECT PhD CANDIDATE

doc.dr.sc. Valerija Majetić Germek, MEDRI

PROJECT COLLABORATOR

CONTACT

INSTITUTE OF AGRICULTURE AND TOURISM

KARLA HUGUESA 8

52440 POREČ

paskovic@iptpo.hr