Determination of antioxidant activity and antioxidant compounds in wild edible mushrooms

The methanolic extracts of dried Agaricus bisporus, Polyporus squamosus, Pleurotus ostreatus, Lepista nuda, Russula delica, Boletus badius, and Verpa conica were analyzed for antioxidant activity in different systems including reducing power, free radical scavenging, superoxide anion radical scavenging, total antioxidant activity, and metal chelating activities. Those various antioxidant activities were compared to standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and α-tocopherol. The percentage inhibition methanolic extracts of dried Russula delica, Boletus badius, Agaricus bisporus, Polyporus squamosus, Pleurotus ostreatus, Lepista nuda and Verpa conica at 100 μg/mL concentrations on peroxidation in linoleic acid system were 99.7%, 99.2%, 98.8%, 98.4%, 98.3%, 97.9% and 97.7%, respectively, and greater than those 400 μg/mL of α-tocopherol, BHA and BHT (77%, 85%, and 97%). Among methanolic extracts from seven wild edible mushrooms, the reducing power of Russula delica and Verpa conica were excellent, and were 1.32 and 1.22 at 200 μg/mL, respectively. Methanolic extract from Verpa conica, Boletus badius and Russula delica proved to be better at scavenging O2− than other mushroom species. The scavenging effects of methanolic extracts from mushroom species and standards on the DPPH radical decreased in the order of BHA>α-tocopherol>Lepista nuda>Russula delica>Polyporus squamosus>Pleurotus ostreatus>Agaricus bisporus>Verpa conica>Boletus badius and were, at the concentration of 180 μg/mL, 97.4, 95.4, 91.3, 86.1, 82.8, 81.3, 77.5, 75.7 and 68.7, respectively. The metal scavenging effect of extract of the mushroom species and standards decreased in the order of Verpa conica>Lepista nuda>Russula delica>Boletus badius>Polyporus squamosus>BHT>Pleurotus ostreatus>Agaricus bisporus>BHA>α-tocopherol. On the other hand, total phenolic compounds, α-tocopherol, and β-carotene were determined in the methanolic extracts of dried Agaricus bisporus, Polyporus squamosus, Pleurotus ostreatus, Lepista nuda, Russula delica, Boletus badius, and Verpa conica.