Composition and Comprehensive Antioxidant Activity of Ginger (Zingiber officinale) Essential Oil from Ecuador

In the present study, the chemical composition and antioxidant potential of an essential oil of ginger rhizomes from Ecuador was elucidated. The analysis of the essential oil by GC/FID/MS resulted in identification of 71 compounds, of which the main are citral (geranial 10.5% and neral 9.1%), α-zingiberene (17.4%), camphene (7.8%), α-farnesene (6.8%) and β-sesquiphellandrene (6.7%). The in vitro antioxidant activity of the essential oil expressed by IC50 in descending order is: hydroxyl radical (OH*) scavenging (0.0065 μg/mL) > chelating capacity (0.822 μg/mL) > 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical cation (ABTS*+) scavenging (3.94 μg/mL) > xanthine oxidase inhibition (138.0 μg/mL) > oxygen radical (O2*) scavenging (404.0 μg/mL) > 2,2- diphenyl-1-picrylhydrazyl radical (DPPH*) scavenging (675 μg/mL). Lipid peroxidation inhibition of the essential oil was less efficient than butylhydroxytoluol (BHT) in both stages, i.e. hydroperoxide and malondialdehyde formation. In vivo studies in Saccharomyces cerevisiae demonstrated a significant dose-dependent increase in antioxidant marker enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), blocking the oxidation processes in yeast cells. Moreover, ginger essential oil in concentrations of 1.6 mg/mL increases the viability of cells to oxidative stress induced by H2O2.