| Abstract | Lišće maslina, predstavlja lako dostupnu i jeftinu sirovinu za izolaciju bioaktivnih spojeva. Ekstrakt lišća masline izrazito je bogat fenolnim spojevima koji imaju farmakološka svojstva, poput antioksidativnih, protuupalnih, antimikrobnih i antivirusnih djelovanja. Oleuropein, kao najzastupljeniji spoj u ekstraktu, pripada skupini sekoiridoida i osim prije navedenih svojstava pokazuje kardioprotektivne i neuroprotektivne učinke, djeluje kao vazodilatator, smanjuje razinu kolesterola i štiti organizam od kognitivnog propadanja. Svrha ovog rada je ekstrakcija, izolacija i kvantifikacija oleuropeina, tirosola, 3-kumarinske kiseline, para-hidroksifeniloctene kiseline, 3-hidroksitirosola i pinorezinola iz tri sorte lišća maslina (Drobnica, Buţa(Labin) i nepoznata sorta (Umag)) s područja Istre. Kvalitativna i kvantitativna analiza ekstrakta lišća maslina provedena je korištenjem kromatografije ultra visoke djelotvornosti (UHPLC). Specifični cilj bio je ispitati utjecaj 3 različita principa ekstrakcije (ekstrakcija s 80%-tnim etanolom pri temperaturi od 70 °C, ekstrakcija s 80%-tnim etanolom pri temperaturi od 78 °C i ekstrakcija s destiliranom vodom pri temperaturi od 90 °C, u trajanju od 4 sata) na koncentraciju fenolnih spojeva u ekstraktu lišća masline i odrediti kojim se principom ekstrakcije i kod koje sorte maslina dobije njihova najveća koncentracija. Dobiveni rezultati su pokazali da koncentracija fenolnih spojeva u ekstraktu lišća masline varira i ovisi o sorti (genetskoj osnovi), starosti masline i uvjetima ekstrakcije. Najveće koncentracije oleuropeina i pinorezinola dobivene su koristeći 80%-tni etanol kao otapalo pri temperaturi od 70 °C, dok su najveće koncentracije 3-hidroksitirosola i tirosola dobivene pri ekstrakciji s destiliranom vodom pri temperaturi od 90°C, za sve tri sorte. Najveća koncentracija oleuropeina iznosi 35,28 mg/g i dobivena je kod stare nepoznate sorte masline s područja Umaga, a najveća koncentracija 3-hidroksitirosola dobivena je kod Drobnice, stare sorte maslinovog lišća s područja Labina i iznosi 2,91 mg/g. Toksičnost i sigurnost otapala koja se koriste u ekstrakciji predstavlja problem u upotrebi ovakvih ekstrakta kao dodataka prehrani, terapeutika i kozmetičkih proizvoda kod ljudi. Stoga su u ovom radu korišteni etanol i voda kako bi dobiveni ekstrakti bili sigurni za upotrebu i poboljšali zdravlje. U budućim istraţivanjima potrebno je optimizirati metode ekstrakcije i ispitati in vitro i in vivo potencijalni terapeutski utjecaj identificiranih komponenti na zdravlje ljudi. |
| Abstract (english) | Olive leaves represent an easily accessible and inexpensive raw material for the isolation of bioactive compounds. Olive leaf extract is extraordinarily rich in phenolic compounds that have many pharmacological properties, such as antioxidative, anti-inflammatory, antimicrobial and antiviral properties. Oleuropein, as the most common compound in the extract, belongs to secoiridoids and in addition to the above mentioned properties, exhibits cardioprotective and neuroprotective effects, functions as a vasodilator, reduces cholesterol levels and protects the organism from cognitive decline. The purpose of this study is the extraction, isolation and quantification of oleuropein, tyrosol, 3-coumaric acid, para-hydroxyphenylacetic acid, 3-hydroxytyrosol and pinoresinol from three varieties of olive leaf (Drobnica, Buţa (Labin) and unknown variety (Umag)) from the area of Istria. Qualitative and quantitative analysis of olive leaf extract was performed using Ultra-high performance liquid chromatography (UHPLC).The specific aim was to examine the influence of solvent and temperature on the extraction (80% ethanol extraction at 70 °C, 80% ethanol extraction at 78 °C (reflux) and extraction with distilled water at 90 °C, for a period of 4 hours) on the concentration of phenolic compounds in olive leaf extract, and determine which extraction technique results in their highest concentration, as well as from which olive variety. The obtained results have shown that the concentration of phenolic compounds in olive leaves varies and depends on the variety (genetic basis), the age of the olive tree and the applied extraction method. The highest concentrations of oleuropein and pinoresinol were obtained using the 80% ethanol as a solvent at a temperature of 70 °C, while the highest concentrations of 3-hydroxytyrosol and tyrosol were obtained by extraction with distilled water at the temperature of 90 °C, in all three varieties. The highest oleuropein concentration is 35,28 mg/g obtained from old unknown olive variety from the Umag area, and the highest concentration of 3-hydroxytyrosol was obtained in the Drobnica variety, a old varietal olive leaf from the Labin area, amounting to 2,91 mg/g. The toxicity and safety of solvents used in extraction represent a problem in using such extracts as dietary supplements, as well as therapeutic and cosmetic products for human consumption. Therefore, ethanol and water have been used in this study so that obtained extracts could be used to improve human health. In future research it is necessary to optimize the extraction methods and to fully examine the potential therapeutic effect of identified components on human health, in vitro and in vitro. |
