Anais do Congresso Paranaense de Microbiologia
Anais do III Congresso Paranaense de Microbiologia

The demand for healthier diet and by the knowledge of the properties of the foods resulted in a comprehensive survey for the evaluation of the antioxidant capacity. Among the foods studied are the mushrooms, a natural source of antioxidants. The objective of this study was to evaluate the antioxidant capacity of the aqueous extracts of Basidiomycete mushrooms mycelium by the ORAC assay (Oxygen Radical Absorbance Capacity). This method has its chemical principle based on the use of a fluorescent compound (e.g. fluorescein) and combines the time and percentage of free radical inhibition by the antioxidant. For the technique, the peroxyl radical (ROO˙) was generated by the reaction of the AAPH with the atmospheric oxygen, and reacted with the fluorescent compound to form a non-fluorescent product, which is measured spectrophotometrically. The decay of the fluorescence in the course of time because of the addition of the antioxidant substance was measured and the area formed under the fluorescence decay curve (AUC) was subtracted from the blank area. A standard curve was generated using Trolox and the ORAC activity of the sample was calculated. The results were expressed in μM of Trolox equivalents (TE)/mg of extract. The mushrooms evaluated were: Flaviporus venustus EF30, Hydnopolyporus fimbriatus EF41 e EF44, Inonotus splitgerberi EF46, Oudemansiella canarii EF72, Perenniporia sp. EF79, Phellinus linteus EF81 e Pleurotus albidus EF84. The high value (1,135.24 ± 17.61 μM TE/mg extract) was obtained for the I. splitgerberi extract, followed by H. fimbriatus EF44 (905.48 ± 23.32) > P. albidus EF84 (860.80 ± 6.99) > F. venustus EF30 (825.91 ± 9.00) > H. fimbriatus EF41 (595.63 ± 9.31) > O. canarii EF72 (421.42 ± 49.68) > P. linteus EF81 (394.03 ± 20.71) > Perenniporia sp. EF79 (251.49 ± 18.03). The results showed the mushrooms can be an important source of antioxidants. This study evaluated for the first time the antioxidant effect of these mushrooms with the ORAC assay.