Antioxidants thymol

At higher concentrations, the antioxidant activities of thymol and carvacrol were close to that of a-tocopherol and were in fact responsible for the antioxidant activity of many EOs which contain them [12, 17, 139, 153, 163, 164, 168, 170-174]. The high potential of phenolic components to scavenge radicals might be explained by their ability to donate a hydrogen atom from their phenolic hydroxyl groups [175]. 

Aeschbach, R., Loliger, J., Scott, B.C., Murcia, A., Butler, J., Halliwell, B. and Aruoma, O.l. (1 994) Antioxidant actions of thymol, carvacrol, 6-gingerol, zingerone and hydroxytyrosol. Food and Chemical Toxicology 32(1), 31-36. 

Thymol is also a true antioxidant and has been used at concentrations of 0.01% as an antioxidant for halothane, trichloroethylene, and tetrachloroethylene. 

It is known that the presence in the oil composition of cyclic monoterpene hydrocarbons having two double bonds in the cycle, i.e. a- and y-terpinene, a-terpinolene, sabinene, and also eugenol, thymol and carvacrol [15] is responsible for the antioxidant properties of the essential oils. However the oil composition is not a constant, depends on taxonomic variety of plants [16], time and conditions of oil storage [17], It was shown that the essential oils of sage [18], savory [19], clove and cardamom [20], coriander [21] and maijoran [22] noticeably varied during a storage and the main process was autooxidation. 

AI3-00708 Caswell No. 856A CCRIS 7299 Cymo-phenol, a- EINECS 201-944-8 ERA Pesticide Chemical Code 080402 FEMA Number 3066 HSDB 866 Isopropyl cresol NSC 11215 Thyme camphor Thymic acid Thymol m-Thymol Thymol (natural). An antibacterial and antifungal agent used in perfumery, microscopy, preservative, antioxidant, flavoring, as a laboratory reagent, in the manufacture of menthol. Used in the prevention of mold and mildew, in flavoring and perfumery, as a preservative and antioxidant and a topical antiseptic. Crystalline solid mp = 51,5° bp = 232.5" dl ... 

A variety of different volatile compounds such as the terpenoids thymol, carvacrol. eugenol, carvone and thujone, which are character-impact compounds for important spices (23,24), have antioxidative activity but the use of these compounds as aiilioxi dants for different foods are limited by the characteristic flavour of the particular compound. 

Extracts derived from most members of the Labiatae family (Table 3) have the potential to reduce the oxidation of food products and extend shelf life. This antioxidant action is dependent on the ability of the constituent phenolics to scavenge free radicals and chelate metals [27]. This dual effect has implications for CHD since it has been proposed in some studies, mainly from Europe, that a high status of iron increases the risk of CHD [28]. A number of the active compounds found in rosemary have also been found in sage and other herbs. In oregano, four flavonoids were identified among the active fraction [29], while in thyme, dimers of thymol and flavonoids have been isolated and characterized. 

Mercaptopropionic acid Methylcyclohexanol Methyl ethyl ketoxime N-Nitrosodiethylamine N-Nitrosodimethylamine Nitrosophenylhydroxylamine ammonium salt Oat (Avena sativa) extract Octadecyl 3-mercaptopropionate Octylphenol 4,4(5H)-Oxazoledlmethanol, 2-(heptadecenyl)-Pansy (Viola tricolor) extract Phenyl neopentylene glycol phosphite Sodium citrate Sulfur dioxide a-Terpineol 2,2, 4,4 -Tetrahydroxy, 5,5 -di-t-butylbenzophenone Tetraisopropyl di (dioctylphosphito) titanate Thymol Toluhydroguinone 2,2,4-Trimethyl-1,2-dihydroquinoline Trimethyl quinoline 2,4,6-Tris (dimethylaminomethyl) phenol Ubiquinone Wheat (Triticum vulgare) germ oil Zeaxanthin Zinc dialkyl dithlophosphate antioxidant mfg. 

The antioxidant performance of carvacrol and thymol in the developed active films was also studied by DSC by determining their oxidation induction time, OIT (min) (Pospisil et al., 2003 Archodoulaki et al., 2006). The OTT value is defined as the time to the onset of an exothermic oxidation peak in oxidative atmosphere and it was determined by using oxygen and air, as the results obtained can be dependent on the type of atmosphere used for the analysis. 

In both cases it was confirmed the higher efficiency of thymol as an antioxidant when compared to carvacrol. This behavior was also reported by other authors who demonstrated that the antioxidant efficiency of thymol was higher in sunflower oil samples [43]. In the case of air atmosphere, as expected, OIT values were higher than those obtained in pure oxygen atmosphere, since the experiment under air is less aggressive to materials [35]. 

In all cases, the increase in OIT values for PP with additives showed the existence of certain antioxidant effect after processing. These results are an additional confirmation that certain amounts of thymol and carvacrol are still remaining in all formulations after processing and they would be able to be released from the material to foodstuff as active additives. 

IC50 value of 3326 g/mL, while the T. marschallianus essential oil had a slightly lower IC50. Thymol showed the best DPPH radical scavenging activity better than BHT (Jia et al 2010). Ichrak et al. (2011) investigated the antioxidant and antibacterial activities of T. pallidus Coss. ex Batt. and T. satureioides Coss. essential oils obtained by steam HD. T. pallidus essential oil revealed to have camphor (29.8%) as a major compound, followed by dihydrocarvone (17.6%), borneol (7.6%), and camphene (7.5%), respectively. T. satureioides contains borneol, carvacrol, and p caryophyllene as most content (29.5%, 9.1%, and 8.2%, respectively). T. pallidus and T. satureioides essential oils exhibited strong antioxidant activity (Ichrak et al., 2011). 

Youdim, K,A, and S,G, Deans, 2000, Effect of thyme oil and thymol dietary supplementation on the antioxidant status and fatty acid composition of the ageing rat hrain, Br. J. Nutr., 83 87-93,... 

The EO of Ziziphora clinopodioid.es ssp. rigida (blue mint bush) was isolated by hydrodistillation of the dried aerial parts, which was collected during the anthesis. The main compounds are thymol and 1,8-cineole with a content of 8% and 2.7%, respectively. Different extracts were tested by the DPPH assay to determine the antioxidative activity and showed that the free radical scavenging activity of the menthol extract was superior to all other extracts. Polar extracts exhibited stronger antioxidant activity than nonpolar extracts (Salehi et al., 2005). 

The leaves, flowers, and stems of Satureja hortensis (summer savory, Lamiaceae), a common plant widely spread in Turkey, are used as tea or as addition to foods on account of the aroma and the flavor. As a medical plant it is known for its antispasmodic, antidiarrheal, antioxidant, sedative, and antimicrobial properties. Also this EO was investigated for its antioxidative properties. The GC-MS analysis showed that besides 9% p-cymene, carvacrol and thymol are the main compounds of about 22 constituents of the oil. They occur at a ratio of approximately 1 1, which is representative for the genus Satureja, namely 29% of thymol and 27% of carvacrol. In a linoleic acid test system the EO showed an inhibition activity of 95%, this is an indicator for a strong antioxidative activity because the control BHT attained an inhibition of 96% (Giilliice et al., 2003). Thymol is one of the main components of the EO from Satureja montana L ssp. montana (savory) and also one of the glycosidically bound volatile aglycones that were found. The EO with 45% thymol shows a very strong antioxidative capacity that was a bit lower than the standards, BHT, and a-tocopherol. The... 

---