Aim and Background : Trametes gibbosa belongs to Polyporaceae family and Polyporales order having many medicinal effects in whole world. The aim of this study is investigation and comparison of antioxidant propertie with two methods DPPH & RP and determination of phenol and flavonoid content.

Materials and Methods : Methanolic extract for examining of antioxidant properties was prepared. Two methods for determining of antioxidant properties were considered as DPPH and RP. BHT and BHA as synthetic antioxidants were considered and we prepared eight concentrations (1000-12.5 µ g/ml) from methanolic extract of fungi, BHT & BHA. Phenol and flavonoid content of methanolic extract T. gibbosa were determined.

Conclusion : antioxidant activities dependent on concentration. DPPH radical scavenging activity was the highest at the concentration of 750 μ g mL^-1 ( 19.61%) and was the lowest at the concentration of 12.5 μ g mL^-1 (4.18%). Reducing power capacity was the highest at the concentration of 1000 μ g mL^-1(0.328) and was the lowest at the concentration of 12.5 μ g mL^-1 (0.129). The total phenol content of methanolic extract was 1.30±0.03 mg GAE g^-1 FW and total flavonoid content of methanolic extract was 1.03± 0.05 mg QUE g^-1 FW.

Results : the results showed that in higher concentrations, antioxidant activity was higher than lower concentrations. In both of methods for determining of antioxidant properties, the results showed that antioxidant activity was strongly dependent on concentration. totally, the result showed that the methanolic extract of the sample no have high antioxidant activity.