Contribution of essential oils and phenolics to the antioxidant properties of aromatic plants

Different in vitro assays characterise most of the essential oils and phenolic compounds as antioxidants. These molecules can be found in a variety of aromatic plants and have been related to their bioactive properties. For the first time, a comparative study between the antioxidant properties of essential oils and phenolic extracts from Cistus ladanifer leaves, Citrus latifolia fruit peels, Cupressus lusitanica foliage and Eucalyptus gunnii leaves was performed. Overall, the antioxidant properties of phenolic extracts (unless scavenging activity of C. latifolia) were excellent and better than those obtained from the essential oils extracts, and even for the standards BHA (2-tert-butyl-4-methoxyphenol) and α-tocopherol. The better EC50 values for all the assays (scavenging activity, reducing power and lipid peroxidation inhibition) were obtained in the E. gunnii phenolic extract (less than 0.1 mg mL−1). Among the essential oils extracts, the best contribution was given by C. ladanifer.