Limonene, linalool and citral are common non-phenolic terpenoid components of essential oils, with attributed controversial antioxidant properties. The kinetics of their antioxidant activity was investigated using the inhibited autoxidation of a standard model substrate. Results indicate that antioxidant behavior of limonene, linalool and citral occurs by co-oxidation with the substrate, due to very fast self-termination and cross-termination of the oxidative chain. Rate constants kp and 2kt, (M−1 s−1) at 30 °C were 4.5 and 3.5 × 106 for limonene, 2.2 and 9.0 × 105 for linalool and 39 and 1.0 × 108 for citral. Behavior is bimodal antioxidant/pro-oxidant depending on the concentration. Calculations at the M05/6-311+g(2df,2p) level indicate that citral reacts selectively at the aldehyde C–H having activation enthalpy and energy respectively lower by 1.3 and 1.8 kcal/mol compared to the most activated allyl position. Their termination-enhancing antioxidant chemistry might be relevant in food preservation and could be exploited under appropriate settings.

Baschieri, A., Ajvazi, M.D., Tonfack, J.L.F., Valgimigli, L., Amorati, R. (2017). Explaining the antioxidant activity of some common non-phenolic components of essential oils. FOOD CHEMISTRY, 232, 656-663 [10.1016/j.foodchem.2017.04.036].

Explaining the antioxidant activity of some common non-phenolic components of essential oils

BASCHIERI, ANDREA;VALGIMIGLI, LUCA;AMORATI, RICCARDO
2017

Abstract

Limonene, linalool and citral are common non-phenolic terpenoid components of essential oils, with attributed controversial antioxidant properties. The kinetics of their antioxidant activity was investigated using the inhibited autoxidation of a standard model substrate. Results indicate that antioxidant behavior of limonene, linalool and citral occurs by co-oxidation with the substrate, due to very fast self-termination and cross-termination of the oxidative chain. Rate constants kp and 2kt, (M−1 s−1) at 30 °C were 4.5 and 3.5 × 106 for limonene, 2.2 and 9.0 × 105 for linalool and 39 and 1.0 × 108 for citral. Behavior is bimodal antioxidant/pro-oxidant depending on the concentration. Calculations at the M05/6-311+g(2df,2p) level indicate that citral reacts selectively at the aldehyde C–H having activation enthalpy and energy respectively lower by 1.3 and 1.8 kcal/mol compared to the most activated allyl position. Their termination-enhancing antioxidant chemistry might be relevant in food preservation and could be exploited under appropriate settings.
2017
Baschieri, A., Ajvazi, M.D., Tonfack, J.L.F., Valgimigli, L., Amorati, R. (2017). Explaining the antioxidant activity of some common non-phenolic components of essential oils. FOOD CHEMISTRY, 232, 656-663 [10.1016/j.foodchem.2017.04.036].
Baschieri, Andrea; Ajvazi, Majlinda Daci; Tonfack, Judith Laure Folifack; Valgimigli, Luca; Amorati, Riccardo
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/596446
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