Influence of extraction methods on the yield of essential oil and phenolic composition of laurel bay leaf (Laurus nobilis L.)

Cilj ovog rada bio je odrediti udio eteričnog ulja i fenolni sastav lista lovora nakon provedene vodene destilacije. Predtretman klasičnom ekstrakcijom refluksiranjem i ekstrakcijom potpomognutom ultrazvukom uz dodatak enzima (celulaza, pektinaza, ksilanaza) neposredno prije provedene Clavenger vodene destilacije nije pridonio povećanju udjela ekstrahiranog eteričnog ulja i udjela fenolnih spojeva iz lista lovora. Spektrofotometrijski su određeni visoki maseni udjeli ukupnih fenola u vodenom ekstraktu (27,27 mg GAE g-1) i ekstraktu biljnog ostatka lista lovora (20,01 mg GAE g-1) koji zaostaju nakon provedene vodene destilacije po Clavengeru. U biljnim ostacima lovora nakon provedene vodene destilacije je ispitivan utjecaj smjese otapala, te su primjenom smjese etanol-metanol-voda (1:1:1) ekstrahirani veći maseni udjeli fenolnih spojeva nego primjenom smjese etanol-voda (1:1) i metanol-voda (1:1).Vodeni ekstrakt, ekstrakt biljnog ostatka, eterično ulje i hidrolat lovora predstavljaju vrijedan izvor biološki aktivnih spojeva, te će se u daljnjim analizama ispitati njihovo djelovanje na patogene oomicete.The aim of this study was to the determine the oil content and phenolic composition of laurel bay. Pretreatment with classical extraction by refluxing and ultrasound-assisted extraction with the addition of enzymes (cellulase, pectinase, xylanase) just prior to the Clevenger hydro-distillation did not contribute to the increase of the extracted essential oil from the laurel bay leaves. In the aqueous extract and the hydrolate that are left behind after Clevenger hydro-distillation are spectrophotometrically determined mass fraction of total phenols, hydroxycinnamic acids, flavonoids and flavonols. After the hydro-distillation the influence of solvent mixture was investigated in the plant residues of the laurel bay leaves and the highest mass fraction of phenolic compounds was extracted using ethanol-methanol-water (1:1:1), while using ethanol-water (1:1) and methanol.water (1:1) significantly less. Aqueous extract, hydrolate and extract of laurel bay leaves are valuable sources of phenolic compounds and in further analysis will be determined their oomicete activity