Influence of the applied extraction method on isolation of bioactive components from lavender : bachelor thesis

Lavanda je mediteranska aromatična biljka koja se zbog atraktivnog izgleda i ugodnog, intenzivnog mirisa najčešće koristi u dekoracijske svrhe ili u pripravi kozmetičkih preparata. Cilj ovog istraživanja je bio istražiti najpogodniju metodu i uvjete ekstrakcije fenolnih spojeva iz lavande te odrediti antioksidacijski potencijal pripravljenih ekstrakata. U istraživanju su korištena dva ekstrakcijska otapala, voda i 80%-tni etanol, a varijacije ekstrakcija su uključivale različito vrijeme ekstrakcije (30, 60 i 90 minuta) u ultrazvučnoj kupelji. Osim toga testirana je i učinkovitost ekstrakcije pri različitim temperaturama (sobnoj temperaturi i pri 60 °C), utjecaj miješanja kao i maceracija u trajanju od 72 h. Sadržaj ukupnih fenola u pripravljenim ekstraktima lavande je određen Folin-Ciocalteu metodom, dok je antioksidacijska aktivnost testirana FRAP (engl. Ferric Reducing/Antioxidant Power) i DPPH (2,2-difenil-1-pikril hidrazil) metodom. Najveća količina fenola izmjerena je u vodenom ekstraktu pripravljenom djelovanjem ultrazvuka tijekom 90 min pri temperaturi od 60 °C (4873 mg GAE/L), dok je najbolju redukcijsku aktivnost pokazao etanolni ekstrakt pripravljen maceracijom pri sobnoj temperaturi tijekom 72 h uz prethodno miješanje tijekom 30 minuta, a antiradikalnu aktivnost etanolni ekstrakt pripravljen djelovanjem ultrazvuka tijekom 90 min pri temperaturi od 60 °C.Lavender is an Mediterranean aromatic plant, which, due to its look and pleasant and intensive smell, is frequently used as an ornament or as an ingredient of the cosmetic products. The aim of this study was to find the best extraction method and conditions for isolation of phenolic compounds from lavender and to test the antioxidant activity of the extracts. For that purpose, two different solvents were used, water and 80% ethanol, and extraction procedures also included variations in the duration (30, 60 and 90 minutes) of treatments using ultrasonic bath. Also, the effectiveness of the process at different temperatures (room temperature and at 60 °C), the influence of the shaking as well as the maceration during 72 h was also investigated. The total phenolic content in the prepared extracts was determined by Folin-Ciocalteu method, while the antioxidant activity was tested using FRAP (Ferric Reducing/Antioxidant Power) and DPPH (2,2- diphenyl-1 picril hydrazyl) assay. The highest concentration of phenolics was detected in water extract prepared by ultrasound during 90 minutes at 60 °C (4873 mg GAE/L), while the best reducing activity was obtained for ethanolic extract prepared by maceration during 72 h with additional stirring during 30 minutes, and antiradical activity was the highest for ethanolic extract prepared using ultrasound during 90 minutes at 60 °C