TURKISH JOURNAL OF BIOLOGY, cilt.35, sa.6, ss.735-742, 2011 (SCI-Expanded)
The objectives of the present study were to determine the effects of essential oil from Turkish oregano (Origanum lutes L.) and its 2 major phenolic components, carvacrol and thymol, on cell viability, and to investigate their cytoprotective (antioxidant) effects against hydrogen peroxide-induced cytotoxicity and membrane damage in hepatoma G2 (Hep G2) cells. Their antioxidant properties were also evaluated with 2 in vitro complementary test systems: DPPH radical scavenging activity and linoleic acid oxidation inhibition. The aerial parts of the essential oil were isolated using a Clevenger-type apparatus (hydrodistillation) and its components were analyzed by gas chromatography/mass spectrometry (GC/MS). The essential oil of O. onites decreased cancer cell viability at higher concentrations. The essential oil was found to be less cytototoxic (IC50: 149.12 mu g/mL) than carvacrol and thymol (IC50: 53.09 and 60.01 mu g/mL, respectively) for Hep G2 cells. On the other hand, with the O. onites essential oil, carvacrol and thymol protected the cells against H2O2-induced cytotoxicity when the cells were preincubated with the oil and its components at a lower concentration (