The antioxidant activities and total phenolics of 28 plant products, including sunflower seeds, flaxseeds, wheat germ, buckwheat, and several fruits, vegetables, and medicinal plants were determined. The total phenolic content, determined according to the Folin−Ciocalteu method, varied from 169 to 10548 mg/100 g of dry product. Antioxidant activity of methanolic extract evaluated according to the β-carotene bleaching method expressed as AOX (Δ log A470/min), AA (percent inhibition relative to control), ORR (oxidation rate ratio), and AAC (antioxidant activity coefficient) ranged from 0.05, 53.7, 0.009, and 51.7 to 0.26, 99.1, 0.46, and 969.3, respectively. The correlation coefficient between total phenolics and antioxidative activities was statistically significant. Keywords: Antioxidant activity; phenolics; medicinal plants; oilseeds; buckwheat; vegetables; fruits; wheat products

Antioxidant Activity and Total Phenolics in Selected Fruits, Vegetables, and Grain Products

Phenolic compounds in plants and agri-industrial by-products: Antioxidant activity, occurrence, and potential uses

Phenolics and polyphenolics in foods, beverages and spices: Antioxidant activity and health effects – A review

This article is a review of the fundamental chemistry of the tocopherols and tocotrienols relevant to their antioxidant action. Despite the general agreement that α-tocopherol is the most efficient antioxidant and vitamin E homologuein vivo, there was always a considerable discrepancy in its “absolute” and “relative” antioxidant effectivenessin vitro, especially when compared to γ-tocopherol. Many chemical, physical, biochemical, physicochemical, and other factors seem responsible for the observed discrepancy between the relative antioxidant potencies of the tocopherolsin vivo andin vitro. This paper aims at highlighting some possible reasons for the observed differences between the tocopherols (α-, β-, γ-, and δ-) in relation to their interactions with the important chemical species involved in lipid peroxidation, specifically trace metal ions, singlet oxygen, nitrogen oxides, and antioxidant synergists. Although literature reports related to the chemistry of the tocotrienols are quite meager, they also were included in the discussion in virtue of their structural and functional resemblance to the tocopherols.

The chemistry and antioxidant properties of tocopherols and tocotrienols

Natural antioxidants from residual sources.

Antioxidant activity and mechanism of action of thymol and carvacrol in two lipid systems

There is a growing interest in natural antioxidants found in plants because of the world-wide trend toward the use of natural additives in food and cosmetics. Herbs and spices are one of the most important targets to search for natural antioxidants from the point of view of safety. This review presents the results on stabilization of lipids and lipid-containing foods with different herbs and spices (ground materials or extracts) and reports the structure of the main antioxidatively acting compounds isolated from them. The review presents information about the antioxidative effects of rosemary, sage, oregano, thyme, ginger, summer savory, black pepper, red pepper, clove, marjoram, basil, peppermint, spearmint, common balm, fennel, parsley, cinnamon, cumin, nutmeg, garlic, coriander, etc. Among the herbs of the Labiatae family, rosemary has been more extensively studied and its extracts are the first marketed natural antioxidants. Sage and oregano, which belong to the same family, have gained the interest of many research groups as potential antioxidants.

Natural antioxidants from herbs and spices

Natural antioxidants have recently gained increased interest because of the belief that natural food ingredients are better and safer than synthetic ones. The review presents the results on stabilisation of the main edible oils with different types of natural antioxidants. Sources of natural antioxidants are spices, herbs, teas, oils, seeds, cereals, cocoa shell, grains, fruits, vegetables, enzymes, proteins. Researchers concentrate on ascorbic acid, tocopherols and carotenoids as well as on plant extracts containing various individual antioxidants such as flavonoids (quercetin, kaemferol, myricetin), catechins or phenols (carnosol, rosmanol, rosamaridiphenol) and phenolic acids (carnosic acid, rosmarinic acid). Ascorbyl palmitate is regarded as a 'natural' antioxidant because it is hydrolysed in the body to ascorbic and palmitic acids. Among the herbs of the Lamiaceae family, rosemary has been more extensively studied and its extracts are the first marketed natural antioxidants. Oregano, which belongs to the same family, has gained the interest of many research groups as a potent antioxidant in lipid systems. The review concerns the following main topics: stabilisation of oil with individual natural antioxidants, interaction of antioxidants with synergists, stabilisation of oil with extracts or dry materials from different plant sources (e.g. herbs and spices), stabilisation at frying temperatures and in emulsions.

Emma M. Marinova

Papers

Antioxidant activity and mechanism of action of thymol and carvacrol in two lipid systems

Natural antioxidants from herbs and spices

Stabilisation of edible oils with natural antioxidants

Antioxidative activity of extracts from selected species of the family Lamiaceae in sunflower oil

Synergistic antioxidant effect of α-tocopherol and myricetin on the autoxidation of triacylglycerols of sunflower oil