Extraction, Phytochemical Analysis, and Standardization of Oleuropein-Rich Olive Leaf Extracts: A Study Across Diverse Jordanian Regions

This study aims to investigate and standardize olive leaf extract (OLE) from Jordanian olive trees, examining the impact of geographical differences on the extract's characteristics. Olive leaves were collected from Amman, Karak, Ajloun, and Mafraq and processed using a cost-effective hydro-alcoholic extraction method. Thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC-UV) were employed to identify and quantify oleuropein, the primary phenolic compound. Additionally, the effects of stress conditions (temperature, UV, humidity) on OLE from Karak were evaluated. The highest oleuropein concentration and total phenolic content were found in extracts from Karak. Physical properties, moisture, ash content, heavy metals, minerals, residual solvents, and microbiological purity were assessed for all extracts. The findings highlight that geographical factors such as altitude and rainfall significantly influence the phenolic content of OLE, with Karak yielding the highest quality extract. The study suggests Jordan's potential as a source of high-quality OLE and recommends further research to improve the stability and formulation of these extracts for therapeutic use.