Insights in the antioxidant synergistic effects of combined edible mushrooms: phenolic and polysaccharidic extracts of Boletus edulis and Marasmius oreades

In a previous work, we reported the presence of Marasmius oreades in mixtures with antioxidant synergistic effects, and the mixture Boletus edulis and Marasmius oreades (50% of each) as having the highest antioxidant activity, but without synergism among the phenolic extracts. Herein, phenolic and polysaccharidic extracts from both species were combined in different proportions (12.5, 25, 50, 75 and 87.5%) and compared to controls (individual samples), in order to give insight in the contribution of each species to antioxidant synergistic effects. The antioxidant activity of the individual or combined extracts obtained from both edible mushrooms was evaluated through their 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity, reducing power, -carotene bleaching inhibition and lipid peroxidation inhibition in brain homogenates using thiobarbituric acid reactive substances (TBARS) assay. Synergism was the main observed effect among the combined extracts, either phenolic or polysaccharidic. However, the effect of each B. edulis and M. oreades proportion was not the same for all antioxidant activity assays. In fact, the same mixture exhibited sometimes opposite behaviours according with the performed antioxidant activity assay.