Antioxidant Activity of Essential Oils

Abstract

Essential oils (EOs) are liquid mixtures of volatile compounds obtained from aromatic plants. Many EOs have antioxidant properties, and the use of EOs as natural antioxidants is a field of growing interest because some synthetic antioxidants such as BHA and BHT are now suspected to be potentially harmful to human health. Addition of EOs to edible products, either by direct mixing or in active packaging and edible coatings, may therefore represent a valid alternative to prevent autoxidation and prolong shelf life. The evaluation of the antioxidant performance of EOs is, however, a crucial issue, because many commonly used "tests" are inappropriate and give contradictory results that may mislead future research. The chemistry explaining EO antioxidant activity is discussed along with an analysis of the potential in food protection. Literature methods to assess EOs' antioxidant performance are critically reviewed.

Nitrogen Nutrition Effect on Aeroponic Basil (<i>Ocimum basilicum </i><spanstyle='mso-bidi-font-style:italic'>L.</span>) Catalase and Lipid Peroxidation

“…There are several methodological differences between the studies which explore the influence of N nutrition in basil plants, such as hydroponic (Kiferle et al, 2013) or field culture (Sifola and Barbieri, 2006), winter (Nurzynska-Wierdak et al, 2013), spring (Kiferle et al, 2013), summer or fall seeding (Nguyen and Niemeyer, 2008) and a wide range of N treatment concentrations from 0.1 mM (Nguyen and Niemeyer, 2008) to 0.9 g dm -3 of growing medium (NurzynskaWierdak et al, 2013) that is 64 mM. In spite of the above alterations, it is considered that in basil plants the increased N nutrition decreases both phenolics concentration and antioxidant activity (Nguyen and Niemeyer, 2008;Kiferle et al, 2013) while enhances the accumulation of essential oils (Sifola and Barbieri, 2006;Nurzynska-Wierdak et al, 2013) which also exhibit antioxidant activity (Amorati et al, 2013). These contradictious findings correspond to our results which indicate that aeroponically treated high N nutrition enhances both the enzymic antioxidative defense in leaves and roots and the leaf oxidative damages, implying that N nutrition induces oxidative stress while the plants develop adaptations of their enzymic and non-enzymic antioxidant defense.…”

Gelatin-Based Films and Coatings for Food Packaging Applications

“…In this context, some studies have reported that natural antioxidants show enough capacity to control lipid oxidation inside the food package since oxidative processes can cause the degradation of proteins, pigments and lipids, which limits food shelf-life [28,56,57]. Table 1 summarizes some research studies performed to enhance the final properties and applicability of food packaging and to extend the shelf-life of food products based on gelatin films and coatings incorporated with antioxidant additives.…”

“…Hydrogen atoms from phenol hydroxyl groups could react with peroxyl radicals produced in the early stages of the oxidation mechanisms to yield stable phenoxyl radicals and, consequently, resulting in the termination of the lipid peroxidation chain reactions. However, understanding the antioxidant activity mechanisms of these phenolic compounds is a hard task since this activity depends on the electronic and steric effects of their ring substituents, the strength of hydrogen-bonding interactions between the phenol and the solvent in the essential oil, and the interactions with matrix and food [56].…”

In Vitro Antioxidant Activity of Chufa Tubers (Cyperus esculentus L.) Extracts in Liposome Peroxidation Systems

“…Also, chufa oil was found to contain remarkable concentration of essential oils (Hassanein et al, 2014). Essential oils were reported to have a powerful antioxidant capacity (Amorati et al, 2013).…”