Thyme, antioxidant activity

In the year 1952, Chipault et al. mentioned that rosemary and sage have the best antioxidant activities, followed by oregano, thyme, clove, allspice and black pepper [28], By using the CO2 extraction the camosolic acid, the most effective substance in this respect, can be enriched to high concentrations. 

In salads or in cooking, olive oil is usually mixed with herbs and spices, which are also important elements of the Mediterranean diet. Herbs like oregano, rosemary, or thyme and others from the plants of the Lamiaceae family are rich sources of phenolic compounds with strong antioxidant activity (Nakatami 1994, Tsimidou and Boskou 1994, Antoun and Tsimidou 1997, Exarchou el al. 2001). These herbs maintain the nutritional value of the food and enhance the shelf life of the food product. 

Antioxidant activity and free radical-scavenging capacity of ethanolic extracts of thyme, oregano, and marjoram. 2009. Eur J Lipid Sci Technol, III, 1111-1117. 

Kulisic, T., Dragovic-Uzelac, V., and Miloc, M. 2006. Antioxidant activity of aqueous tea infusions prepared from oregano, thyme and wild thyme. Food Technology and Biotechnology, 44, 485-492. 

Miura, K., Kikuzaki, H., and Nakatani, N. 2002. Antioxidant activity of chemical compounds of sage (Salvia officinalis) and thyme (Thymus Vulgaris) measured by the oil stability index method. Journal of Agricultural and Food Chemistry, 50, 1850-1855. 

Antioxidant and antimicrobial effects are found in some simple phenols (especially hydroquinone, guaiacol, isoeugenol and saU-cylaldehyde) that occur as components of smoke, which has been used for smoking foods since ancient times. Phenols, which are components of some common spices, also have high antioxidant activities. In common thyme Thymus vulgaris, Lamiaceae), for example, thymol and carvacrol occur (see Section 8.2.8.1). 

Mint plants (Lamiaceae), for example in common thyme (ThymtAS vulgaris), contain substituted biphenyls derived from monoter-penic alcohol thymol, their o-quinones (10-178) or p-quinones (10-179), which exhibit marked antioxidant activities. Among the most active natural antioxidants with anti-inflammatory effects is carnosic acid, also known as rosmaricine (10-180), which is accompanied by carnosol (picrosalvin, 10-181). These two antioxidants represent about 15% by weight of commercial extracts of rosemary... 

Roby, M., M. Atef Sarhan, K. A. Selim, and K. I. Khalel. 2013. Evaluation of antioxidant activity, total phenols and phenolic compounds in thyme (Thymus vulgaris L.), sage (Salvia officinalis L.), and marjoram (Origanum majorana L.) extracts. Ind. Crops Prod. 43(1) 827-831. 

Thyme oil and thymol have been demonstrated to have antioxidative activities on dehydrated pork. The labiatic acid present in thyme as well as in maqoram, oregano, sage, and other plants of the mint family also has antioxidative properties (see maijonan, rosemary, and sage). 

Extracts and leaves of rosemary and sage have the most effective antioxidant activities, but some are recognized in oregano, clove, thyme, pepper, and allspice. Supercritical CO2 extraction enables enrichment of camosolicacidfromrosemaryup to concentrations of 25 wt%-30 wt%. Figure 8.12 shows that nearly exhaustive extraction of carnosolic acid is possible at elevated pressures. Stability tests on lard (based on peroxide numbers) demonstrated that CO2 extracts had higher lifetimes compared to BHA (butylhydroxyanisole), up to about 2.5 times higher in case of 700 bar extracts. 

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. 

Odoriferous substances and their mixtures (e.g. essential oils) show a number of beneficial effects for which they have found use as pharmaceuticals, pharmaceutical ingredients and food additives. Bactericidal and anti-inflammatory effects are seen in bomeol, eugenol, pinenes, camphor, thymol and menthol, choHnolytic (spasmolytic) effects preventing a drop in blood pressure and suppressing the secretory activity of various organs are found in camphor, pinenes and camphene, and analeptic effects (stimulating activity of circulation and respiratory system) are seen in camphene. The essential oils of many spices (such as marjoram, sage, thyme and many others) exhibit antioxidant effects, and therefore find use as natural antioxidants of fats. 

The most frequently studied activity of thyme is the antioxidant effect of its extracts, volatile oil, and main constituents. Free radical scavenging and protective effects against hepa-... 

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