Potential anticancer activity of chemically characterized extract of Olea europaea (Olive) leaves

Olea europaea Linn. (Olive) is considered as essential component of Mediterranean diets. Olive leaves, fruits, and oil are traditionally known for several health benefits including diabetes, cardiac complications, cancer, etc. The objective of the present study is to determine the anticancer potential of chemically characterized O. europaea extract in MTT assay and EB/AO double staining method using Human lung cancer cell lines (A549). The chemical constituents present in the ethyl acetate extract of O. europaea leaves were characterized by GC-MS and its cytotoxic activity was assessed by MTT assay and EB/AO double staining method. The GC-MS analysis identified 63 chemical constituents, and neophytadiene (21.80%), zingiberenol (12.36%), and allohimachalol (5.49%) was found as major chemical constituents in ethyl acetate extract of O. europaea leaves. O. europaea produces a time and dose-dependent inhibition of cell proliferation of A549 cell lines. The cell viability of A549 cell lines after 24 hrs treatment with O. europaea ranged from 97.96±3.44 to 18.95±2.14 % for a concentration range of 0.5-500 μg/mL, respectively, with IC50 value of 21.91±1.8 μg/mL. EB/AO double staining shows significant apoptosis in early and late apoptotic, and necrotic cells with increased volume and showed uneven orange-red fluorescence at their periphery. The study outcome shows that O. europaea extract significantly inhibited cell proliferation and apoptosis in human lung cancer (A549) cell lines, and it also explores the chemical composition of O. europaea leaves extract. Keywords: Apoptosis, A549 cell lines, Cancer, GC-MS, MTT assay, Olea europea, Olive.