Antioxidant activity of six Portuguese thyme species essential oils

Abstract

The essential oils of Thymus caespititius, T. camphoratus, T. capitellatus, T. carnosus, T. pulegioides, T. zygis subsp. zygis and T. zygis subsp. sylvestris collected in diff erent regions of Portugal, including the Azores islands, were evaluated for preventing lipid peroxidation and scavenging free radicals, and hydroxyl and superoxide anions. T. zygis subsp. zygis oil possessed the best capacity for preventing lipid peroxidation (IC 50 = 0.030 ± 0.003 mg/ml), immediately followed by the oils isolated from T. zygis subsp. sylvestris collected in diff erent regions of Portugal. IC 50 values ranged from 0.066 ± 0.003 to 0.087 ± 0.001 mg/ml in oils isolated from samples from Alcanena and Duas Igrejas, respectively. The oils isolated from T. zygis subsp. sylvestris, independent of the harvesting region, were shown to be the most eff ective for scavenging free radicals (0.358-0.453 mg/ml). The best capacity for scavenging hydroxyl radicals was found in the oils of T. camphoratus collected in Espartal and of T. caespititius of Lordelo, with IC 50 < 0.5 mg/ml. The low oil amount did not allow IC 50 values for the superoxide anion scavenging determination, therefore considering a unique oil concentration (5 mg/ml), the highest inhibition percentages (>50%) were registered with the essential oils of T. zygis subsp. sylvestris from Duas Igrejas and Covão do Coelho, and of T. capitellatus from Sines.

Anticancer and Antioxidant Activities of Some Algae from Western Libyan Coast

“…Free radical-scavenging activities of extracts were measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) as described by Dandlen et al, (2010) [30]. The percentage inhibition of the DPPH radical by the samples was calculated according to the following equation: % Inhibition = (A0 − A1)/ A0 × 100, where A0 is the absorption of the blank sample (t = 0 minutes) and A1 is the absorption of the tested extract solution (t=60 minutes).…”

Antimicrobial activity, cytotoxicity and intracellular growth inhibition of Portuguese Thymus essential oils

“…Four essential oil concentrations were tested (0.08 mg.mL -1 , 0.50 mg.mL -1 , 1.00 mg.mL -1 and 2.00 mg.mL -1 ). The tested essential oils concentrations were selected according the obtained MIC value for H. pylori and the higher values in the base of the IC 50 value that corresponds to different antioxidant activities (Dandlen et al, 2010). All determinations were done in triplicate and, for control, the RPMI 1640 culture medium with no essential oil added, supplemented with 2-propanol and 5% H 2 O 2 (v/v) (cytotoxic agent, positive control), was used.…”

Thymus lotocephalus wild plants and in vitro cultures produce different profiles of phenolic compounds with antioxidant activity

“…Thymus spp. also produce secondary metabolites that can be used as antioxidants, expectorants, antitussives, antiplatelet drugs, antimicrobials and drugs for the treatment of skin disorders (Dandlen et al, 2010;Faleiro et al, 2003;Figueiredo et al, 2008;Hazzit, Baaliouamer, Veríssimo, Faleiro, & Miguel, 2009;Oh et al, 2009;Okazaki, Kawazoe, & Takaishi, 2002). Thymus lotocephalus G. López & R. Morales is an aromatic species endemic to the Algarve region, which blossoms from April to June and is typically found in dry open areas and scrublands (Figueiredo et al, 2001(Figueiredo et al, , 2008.…”