Antioxidant capacity of the essential oils from Lavandula luisieri, L. stoechas subsp. lusitanica, L. stoechas subsp. lusitanica x L. luisieri and L. viridis grown in Algarve (Portugal)

The antioxidant capacity of the essential oils isolated from the aerial parts of Lavandula luisieri, L. stoechas subsp. lusitanica, the hybrid L. stoechas subsp. lusitanica x L. luisieri, and L. viridis collected in different regions of Algarve (Portugal), as well as that of butylated hydroxytoluene (BHT), was evaluated using three different methods: free radical scavenging activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, thiobarbituric acid reactive substances assay (TBARS) and reductive potential. The chemical composition of the essential oils was analyzed by GC and GC/MS. The oils of L. luisieri were mainly constituted by 1,8-cineole (26-34%) and trans-α-necrodyl acetate (11-18%), only present in this lavender species. The oils of Lavandula stoechas subsp. lusitanica and the hybrid L. stoechas subsp. lusitanica x L. luisieri were dominated by fenchone (42-44%) and camphor (35-36%). Despite of the morphological resemblances of the L. stoechas subsp. lusitanica x L. luisieri with L. luisieri, no necrodane derivatives were detected in the hybrid, showing instead a major chemical similarity with L. stoechas oil. Lavandula viridis oil mainly comprised 1,8-cineole (33%) and camphor (20%). The oils of L. luisieri were the most effective as antioxidants, independent of the evaluation method used, although showing always lower antioxidant ability than BHT.