A comparative study of tocopherols composition and antioxidant properties of in vivo and in vitro ectomycorrhizal fungi

In aerobic organisms, the free radicals are constantly being produced during the normal cellular metabolism. The antioxidant properties of many organisms and particularly of wild mushrooms with their content in antioxidant compounds such as tocopherols, can detoxify potentially damaging forms of activated oxygen. Herein, a comparative study of tocopherols composition and antioxidant properties of in vivo (fruiting bodies) and in vitro (mycelia) ectomycorrhizal fungi: Paxillus involutus and Pisolithus arhizus. Tocopherols were determined by high performance liquid chromatography (HPLC) coupled to a fluorescence detector. The antioxidant properties were studied in terms of DPPH radical-scavenging activity, reducing power and inhibition of β-carotene bleaching. Fruiting bodies revealed the highest antioxidant properties, including scavenging effects on free radicals (EC50 = 0.61 and 0.56 mg/ml) and inhibition of lipid peroxidation capacity (EC50 = 0.40 and 0.24 mg/ml for P. involutus and P. arhizus, respectively), than mycelia produced in vitro cultures. Nevertheless, mycelia revealed higher levels of total tocopherols than fruiting bodies, and particularly P. arhizus mycelium proved to be a powerful source of γ-tocopherol (154.39 μg/g dry weight).