Investigation of Chemical Compounds and DPPH Radical Scavenging Activity of Oudemansiella raphanipes (Agaricomycetes) Based on Fermentation

Oudemansiella raphanipes, an edible medicinal mushroom, is very popular in the market. With the development of technology, liquid fermentation is becoming more and more popular in edible fungi cultivation. Strain O. raphanipes was cultured by submerged fermentation and secondary metabolites were investigated simultaneously. Six chemical constituents including two unsaturated fatty acids (1-2), one ergosterol (3), one phenol (4), and two benzamides (5-6) were acquired from ethyl acetate extract. Their structures were mainly elucidated by NMR spectral data and known products. All compounds were isolated from O. raphanipes for the first time. DPPH radical scavenging activity was evaluated. Orcinol (4) exhibited remarkable antioxidant activity; its free radical scavenging rate can reach up to 80% of 20 mg/mL. 2-pyruvoybenzamide (5) and 2-(2-hydroxypropanamido) benzamide (6) showed less active antioxidant capacity.