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 ß-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.

Chemical Composition and Antioxidant Properties of Juniper Berry (Juniperus communis L.) Essential Oil. Action of the Essential Oil on the Antioxidant Protection of Saccharomyces cerevisiae Model Organism.

The essential oil of juniper berries (Juniperus communis L., Cupressaceae) is traditionally used for medicinal and flavoring purposes. As elucidated by gas chromatography/flame ionization detector (GC/FID) and gas chromatography/mass spectrometry (GC/MS methods), the juniper berry oil from Bulgaria is largely comprised of monoterpene hydrocarbons such as α-pinene (51.4%), myrcene (8.3%), sabinene (5.8%), limonene (5.1%) and ß-pinene (5.0%). The antioxidant capacity of the essential oil was evaluated in vitro by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging, 2,2-azino-bis-3-ethylbenzothiazoline-6 sulfonic acid (ABTS) radical cation scavenging, hydroxyl radical (ОН(•)) scavenging and chelating capacity, superoxide radical ((•)O2(-)) scavenging and xanthine oxidase inhibitory effects, hydrogen peroxide scavenging. The antioxidant activity of the oil attributable to electron transfer made juniper berry essential oil a strong antioxidant, whereas the antioxidant activity attributable to hydrogen atom transfer was lower. Lipid peroxidation inhibition by the essential oil in both stages, i.e., hydroperoxide formation and malondialdehyde formation, was less efficient than the inhibition by butylated hydroxytoluene (BHT). In vivo studies confirmed these effects of the oil which created the possibility of blocking the oxidation processes in yeast cells by increasing activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx).

Chemical composition, olfactory evaluation and antioxidant effects of essential oil from Mentha x piperita.

The chemical composition of the essential oil from peppermint (Mentha x piperita L.) was analyzed by GC/FID and GC-MS. The main constituents were menthol (40.7%) and menthone (23.4%). Further components were (+/-)-menthyl acetate, 1,8-cineole, limonene, beta-pinene and beta-caryophyllene. Peppermint oil possessed antiradical activity with respect to DPPH (diphenyl picryl hydrazyl) and hydroxyl (OH*) radicals, exercising stronger antioxidant impact on the OH* radical. The concentrations required for 50% inhibition of the respective radical (IC50) were 860 microg/mL for DPPH and 0.26 microg/mL for OH*. Peppermint essential oil demonstrated antioxidant activity in a model linoleic acid emulsion system in terms of inhibiting conjugated dienes formation by 52.4% and linoleic acid secondary oxidized products generation by 76.9% (at 0.1% concentration).

Chemical composition, olfactory evaluation and antioxidant effects of essential oil from Mentha canadensis.

The chemical composition of the essential oil from cornmint (Mentha canadensis L.) was analyzed by GC/FID and GC-MS. The main constituents were menthol (41.2%) and menthone (20.4%). It was established that cornmint oil had antiradical activity with respect to the DPPH and hydroxyl (OH*) radicals. The concentrations necessary for 50% neutralization of the respective radicals (IC50) were 365.0 microg/mL for DPPH and 0.3 microg/mL for OH*, which was indicative that the antioxidant activity in terms of OH* was higher than that of quercetin. Cornmint oil chelated the Fe3+ ions present in the solution. The oil demonstrated antioxidant activity in a linoleic acid emulsion model system, where at 0.1% concentration it inhibited the formation of conjugated dienes by 57.1% and the generation of secondary oxidized products of linoleic acid by 76.1%.

Chemical composition and antioxidant properties of clove leaf essential oil.

The antioxidant activity of a commercial rectified clove leaf essential oil (Eugenia caryophyllus) and its main constituent eugenol was tested. This essential oil comprises in total 23 identified constituents, among them eugenol (76.8%), followed by beta-caryophyllene (17.4%), alpha-humulene (2.1%), and eugenyl acetate (1.2%) as the main components. The essential oil from clove demonstrated scavenging activity against the 2,2-diphenyl-1-picryl hydracyl (DPPH) radical at concentrations lower than the concentrations of eugenol, butylated hydroxytoluene (BHT), and butylated hydroxyanisole (BHA). This essential oil also showed a significant inhibitory effect against hydroxyl radicals and acted as an iron chelator. With respect to the lipid peroxidation, the inhibitory activity of clove oil determined using a linoleic acid emulsion system indicated a higher antioxidant activity than the standard BHT.