Essential oils as antioxidants

Essential oils (EO) are widely used in the perfume, cosmetic, pharmaceutical, agricultural and food industries. They have been recognised since antiquity to possess biological activities, including antibacterial, antifungal, antiviral, antitoxigenic, antiparasitic and insecticidal properties. In recent years, a large number of essential oils and their constituents have been investigated for their antioxidant properties. This paper reviews the classical methods commonly used for the evaluation of the antioxidant activities of essential oils. The P-carotene bleaching test and the TBARS (thiobarbituric acid reactive species) method as well as radical scavenging tests (ABTS and DPPH tests) in the presence of tested essential oils are described. Factors influencing the antioxidant activity of essential oils and the mechanisms of essential oil action on oxidants are reported. This paper gives an overview on the antioxidant activity of different essential oils and their constituents.