Biological effects of essential oils - A review

Comparative evaluation of 11 essential oils of different origin as functional antioxidants, antiradicals and antimicrobials in foods

https://bib.irb.hr/datoteka/145388.29.pdf

Use of different methods for testing antioxidative activity of oregano essential oil

The antioxidant properties of the essential oil from oregano in relation to its chemical composition were examined. The antioxidant activity was investigated with three different methods: the b-carotene bleaching (BCB) test, the 2,2 0 -diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method and the thiobarbituric acid reactive species (TBARS) assay. It was found that the total essential oil, its fraction as well as its pure constituents have a significant antioxidant effect when tested by each method, respectively. Generally the antioxidant activity of the oregano essential oil is less effective than the ascorbic acid, but comparable with the a-tocopherol and the synthetic antioxidant butylated hydroxytoluene (BHT). The synergy among minor oxygen containing compounds was suggested as possible factor, which influenced the antioxidant power of the oregano essential oil. The antioxidant concentrations influenced its antioxidant power, too. # 2003 Elsevier Ltd. All rights reserved.

Analytical, Nutritional and Clinical Methods Use of different methods for testing antioxidative activity of oregano essential oil

The essential oils of rosemary ( Rosmarinus officinalis L.) and sage ( Salvia officinalis L.) were analyzed by means of gas chromatography-mass spectrometry and assayed for their antimicrobial and antioxidant activities. Antimicrobial activity was tested against 13 bacterial strains and 6 fungi, including Candida albicans and 5 dermatomycetes. The most important antibacterial activity of both essential oils was expressed on Escherichia coli, Salmonella typhi, S. enteritidis, and Shigella sonei. A significant rate of antifungal activity, especially of essential oil of rosemary, was also exhibited. Antioxidant activity was evaluated as a free radical scavenging capacity (RSC), together with the effect on lipid peroxidation (LP). RSC was assessed by measuring the scavenging activity of essential oils on 2,2-diphenyl-1-picrylhydrazil (DPPH) and hydroxyl radicals. Effects on LP were evaluated following the activities of essential oils in Fe(2+)/ascorbate and Fe(2+)/H2O2 systems of induction. Investigated essential oils reduced the DPPH radical formation (IC50 = 3.82 microg/mL for rosemary and 1.78 microg/mL for sage) in a dose-dependent manner. Strong inhibition of LP in both systems of induction was especially observed for the essential oil of rosemary.

Antimicrobial and antioxidant properties of rosemary and sage (Rosmarinus officinalis L. and Salvia officinalis L., Lamiaceae) essential oils.

Antioxidant activity of selected essential oil components in two lipid model systems

The antioxidant activity of the lipid extracts of eight marine algae belongingto the Cystoseira genus has been evaluated in a micellar model system.The activity has been ascribed to the presence in the extracts oftetraprenyltoluquinols, which are tocopherol-like compounds characteristicof these algae. Results have been expressed as relative antioxidant efficiency(RAE), defined as the ratio of the antioxidant efficiency (AE) of the testedextract to that of α-tocopherol. From the results a composition-activityrelationship has been deduced.

Maria T. Baratta

Papers

Antioxidant activity of selected essential oil components in two lipid model systems

Antioxidant activity of extracts of the marine algal genus Cystoseira in a micellar model system