Antimicrobial Effects of the Water Immiscible Solvent Extracts of Olive Tree Leaves

Abstract

The purpose of this work was to perform the phytochemical and antimicrobial activity evaluation of the water-immiscible solvent extracts of Olive tree leaves (Olea europaea L., Family: Oleaceae). Seven sample extracts of the leaves of O. europaea were obtained using dichloromethane (DCM), dichloroethane (DCE) along with their mixtures with chloroform (CH), and ethyl acetate (EA). The phytochemical studies were carried out using the standard procedures. Serial plate dilution technique was used to perform the antimicrobial activity of the extracts. The phytochemical tests revealed the presence of steroids, terpenoids, saponins and flavonoids in all extracts of olive leaves. The 1:1 mixture of ethyl acetate and dichloromethane (EA:DCM) exhibited equivalent MIC (20 µgml-1, 100%) values concerning Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa with respect to ofloxacin (MIC = 20 µgml-1, 100%). Similarly, the 1:1 mixture of ethyl acetate and dichloroethane (EA:DCE) exhibited equivalent MIC (20 µgml-1, 100%) values concerning E. coli and P. aeruginosa with respect to ofloxacin (MIC = 20 µgml-1, 100%). The 1:1 mixture of EA:DCM and EA:DCE showed moderate antifungal activity (MIC = 20 µgml-1, 75%) with respect to fluconazole against Aspergillus niger and Candida albicans. The water immiscible solvent extracts showed more potent antimicrobial activity than the water extract of the olive leaves, which might be because of the presence of the lipophilic compounds in the water immiscible solvent extracts of the olive leaves. It is also expected that by increasing the concentration of ethyl acetate in EA:DCM & EA:DCE solvent system may further provide better MIC values.

Keywords

• olive leaves
• water immiscible solvent
• extract
• antimicrobial