Investigatıon of Antioxıdative, Cytotoxic, Membrane-Damaging and Membrane-Protective Effects of The Essentıal Oil of Origanum majorana and its Oxygenated Monoterpene Component Linalool in Human-Derived Hep G2 Cell Line.

The aim of our work was to compare cytotoxic and membrane-damaging effects of O. majorana L. essential oil and linalool on Hep G2 and to investigate their possible protective (antioxidant) effects against H2O2 induced membrane damage. The oils were investigated by GC and GC-MS and antioxidant activity was evaluated by DPPH and -carotene–linoleic acid assays. Assessment of cell viability was made by The CellTiter-Blue® Cell Viability Assay. Also, malondialdehyde levels in Hep G2 cells were assayed after IC10, IC50 and IC70 essential oil and linalool concentrations treated for 24 h.Five components were identified in the essential oil and the major components of the oil were carvacrol (52.5%) and linalool (45.4%). After 24, 48 and 72 hours incubations IC50 values were calculated respectively, for essential oil 100, 80 and 63 μg/mL, for linalool 81.5, 72.7 and 64.7 μg/mL. The essential oil was able to reduce the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) with an EC50 of 170 μg/mL. Inhibition value of linoleic acid oxidation was calculated as 40% for the oil. Preincubation with the essential oil and linalool increased cell viability against H2O2 cytotoxicity. The essential oil and its oxygenated monoterpene component linalool significantly decreased membrane-damaging on H2O2 treated Hep G2 cells.