Elaeagnus angustifolia has many potential applications in drugs, detergents, perfumes, herbal teas and show various biological and pharmacological activities, such as anti-inflammatory, antipyretic and other effective treatment of disease. Gallic acid (GA) and its derivative methyl gallate (MG) are well studied plant phenolics. They have exhibited anticancer effects in several cancer cell lines. In the present work, The E. angustifolia leaves were collected from the enclosure of Azerbaijan Shahid Madani University trees and were dried in the shade condition, were milled and extracted successively with n-hexane, ethyl acetate and methanol in a Soxhlet apparatus for 24 h. Further study on the methanol extract of this plant has resulted in the isolation of gallic acid. The structure of the compound was established by spectroscopic methods. Antioxidant properties of flavonoid and phenolic compoundes were measured.