Novel 2,5-Diarylcyclopentenone Derivatives from the Wild Edible Mushroom Paxillus involutus and Their Antioxidant Activities.

Wild edible mushrooms are important as a source of nutraceuticals and for the discovery of bioactive metabolites as pharmaceuticals. In this work, 10 rare 2,5-diarylcyclopentenone derivatives were isolated from the wild edible mushroom Paxillus involutus (Batsch) Fr., including eight novel compounds termed involutenone A-H (1-8) and two previously identified compounds (9-10). Their structures were established using high-resolution electrospray ionization mass spectroscopy and 1D and 2D nuclear magnetic resonance data. The absolute configurations of compounds 1-3 and 6-8 were assigned based on the comparison of the experimental and calculated electronic circular dichroism data. The antioxidant activities of 1-8 were tested through DPPH free radical scavenging, hydroxyl radical scavenging, and superoxide anion radical scavenging assays. Compounds 3, 5, 6, and 7 demonstrated significant antioxidant activity compared to the positive control (tert-butylhydroquinone). These compounds could be effective natural antioxidants with considerable pharmaceutical value.