Antioxidant activity of mediterranean plant leaves: Occurrence and antioxidative importance of A-tocopherol

a-Tocopherol was identified as the main antioxidant in hexane extracts of leaves of sixteen Mediterranean plant species. The a-tocopherol content was determined by a two-step procedure involving column and gas chromatog- raphy with a-tocopherol acetate as internal standard. The tocopherol content of the extracts was in the range of 0.0-4.7%, and that of the dry leaves was 0-846 ppm. The highest a-tocopherol content was found in the leaves of a Mediterranean oak, Quercus ilex. The antioxidative ac- tivity, which was previously investigated, was correlated with the a-tocopherol content. Correlation coefficients were 0.947 and 0.904 for extracts and leaves, respectively.