Natural Antioxidants: Sources, Compounds, Mechanisms of Action, and Potential Applications

Abstract

While use of synthetic antioxidants (such as butylated hydroxytoluene and butylated hydroxyanisole) to maintain the quality of ready-to-eat food products has become commonplace, consumer concern regarding their safety has motivated the food industry to seek natural alternatives. Phenolic antioxidants can inhibit free radical formation and/or interrupt propagation of autoxidation. Fat-soluble vitamin E (α-tocopherol) and water-soluble vitamin C (L-ascorbic acid) are both effective in the appropriate matrix. Plant extracts, generally used for their flavoring characteristics, often have strong H-donating activity thus making them extremely effective antioxidants. This antioxidant activity is most often due to phenolic acids (gallic, protocatechuic, caffeic, and rosmarinic acids), phenolic diterpenes (carnosol, carnosic acid, rosmanol, and rosmadial), flavonoids (quercetin, catechin, naringenin, and kaempferol), and volatile oils (eugenol, carvacrol, thymol, and menthol). Some plant pigments (anthocyanin and anthocyanidin) can chelate metals and donate H to oxygen radicals thus slowing oxidation via 2 mechanisms. Tea and extracts of grape seeds and skins contain catechins, epicatechins, phenolic acids, proanthocyanidins, and resveratrol, all of which contribute to their antioxidative activity. The objective of this article is to provide an overview of natural antioxidants, their mechanisms of action, and potential applications.

Natural antioxidants as stabilizers for polymers

“…More than hundred diseases are caused by or lead to oxidative stress [16][17][18]. Living organisms synthetize various substances with strong antioxidant effect in order to reduce the amount of reactive oxygen species and other free radicals [14,19,20]. The reaction mechanisms of these species are similar to those of polymer stabilizers [18].…”

“…Endogenous byproducts (peroxides, transition metals) and exogenous exposure, like UV and other radiations with higher energy and heat, lead to the formation of reactive oxygen-and nitrogen species [14], such as hydrogen peroxide (H 2 O 2 ), superoxide (O 2 -• ), singlet oxygen ( 1 O 2 ) hydroxyl (OH • ), peroxy (ROO • ) and alkoxy (RO • ) radicals [15]. More than hundred diseases are caused by or lead to oxidative stress [16][17][18].…”

Extraction, fractionation and assessment of antioxidant activities of active components of Aframomum sceptrum seeds

“…Synthetic antioxidants may result in liver swelling and influence liver enzyme activities (Yoshihara et al, 2010). Therefore, considering these reports and the present trends towards naturally preserved food products, herbs and spices have been targeted as sources of natural antioxidants (Kimura et al, 2010;Brewer, 2011). The use of these plant materials as natural antioxidants for food, cosmetics and other application becomes necessary because of food safety issues: (1) safety, since they are part of food man has been eating for thousands of years *Corresponding author.…”

Chestnut flowers as functionalizing agents to enhance the antioxidant properties of highly appreciated traditional pastry

“…Although quite important for the food chain, these chemicals are becoming increasingly untrusted by many consumers throughout the world due to some known negative effects towards health that are attributed to them. Therefore, the use of natural additives, from plants and other matrices, has become more notorious, especially due to the added value of antioxidant benefits to the consumers [7][8][9] . Minced meat, meat balls, cheese and biscuits are some examples of food products functionalized with natural extracts [10][11][12][13] .…”