Determination of Oleuropein in leaves and fruits of some Syrian olive varieties

Oleuropein contents (OLE) in leaves and fruits of from seven olive Syrian varieties harvested at spring and fall were determined by high-performance liquid chromatography. The results showed that, the concentration of OLE leaves samples measured in spring was higher than those determined in fall samples, where the OLE concentration in spring samples ranged between 5.6 9.2 mg/g. The highest concentration (9.2 mg/g dry leaves), was found in Jlott variety and the lowest concentration (5.6 mg/g dry leaves) was in Dan mawi. In fall olive leaves samples, the concentration of OLE ranged between 4.3 to 8.2 mg/g dry leaves, where the highest concentration was in Jlott variety and the lowest was in Dan mawi variety. As for fruit samples, the OLE concentration ranged between 635-1026 mg/kg, where the highest value was in Jlott variety, and the lowest was in Kaissy variety. Comparisons between olive oil content in fruits and oleuropein content in leaves (in spring and autumn) (using student T test statistical analysis) indicate that the differences in oleuropein contents are affected by the genetic makeup of the olive varieties and not by the environment.