Determination and Identification of The Biologically Active Compounds in Olive Leaves

Olive leaf extract (OLE) is one of the natural extracts utilized to obtain bioactive components. It contains the potential sources of several phenolic compounds. The total flavonoid concentration, total phenolic content, antioxidant activity, and drying procedures of OLE, air-dried (AD), freeze-dried (FD), and fresh extract (FE) were evaluated via HPLC. LC‒MS/MS characterization and identification were subsequently conducted to obtain additional structural information on theseparated compounds. The extract obtained using ethanol (80%) had a high total phenolic content (114.55 FD, 91.95 AD, and 63.41 mg FE/g dw) and TFC (251.25 FD, 254.43 AD, and 111.67 mg FE/g dw). Additionally, the DPPH technique was used to assess the antioxidant activity of OLE (82.43 FD, 89.53 AD, and 64.13 mg FE/g dw). HPLC was used to characterize and identify 21 bioactive compounds. Phenolic compounds such as Oleuropein, Apigenin-7-O-glucoside, Luteolin-7-Oglucoside, Luteolin, Quercetin, Homo vanillic acid, Apigenin, Hydroxytyrosol, Caffeic acid, Tyrosol, and Vanillin were identified via the LC‒MS/MS profile of OLE. The results of this study indicate that the bioactive components obtained from olive leaf extract are valuable sources of antioxidants, which may lead to applications in the pharmaceutical and food industries.