Essential Oil Composition of Oleaster (Elaeagnus Angustifolia L.) Flowers and Comparative Assessment of Metabolic and Antioxidant Potential of Flower and Leaf Extracts

The oleaster tree (Elaeagnus angustifolia L.) has different uses and is cultivated for fruit production, afforestation, landscape, as well as for food and medicinal purposes. The present study was conducted to identify volatile compounds of flowers and assess total phenolic, flavonoid, carotenoid and chlorophyll content of flowers and leaves and their antioxidant potentials. Oil yield of flowers was low (0.1%), 15 compounds were identified in flower oils, and the main volatile compounds were ethyl-cinnamate (93.87%) and ethyl phenylacetate (1.76%). The others were belong to six chemical class and accounted for less than 5% of oil. Total phenolic content of flowers was higher than that of leaves, but total flavonoid, carotenoid and chlorophyll content was higher in leaves. However, the antioxidant capacity measured by CUPRAC (67.49 vs 53.25 µmoL TE-1) and the radical scavenging activity measured by DPPH (22.30 vs 7.57 µmoL TE-1) were higher in flower extracts than the leaf extracts. These results suggest that oleaster flowers are a good source of ethyl-cinnamate and phenolic compounds.