A New Antioxidant, Clitocybin A, from the Culture Broth of Clitocybe aurantiaca

Clitocybin A (1), a new antioxidant, was isolated from the culture broth of Clitocybe aurantiaca. This compound was purified by solvent extraction, silica gel column chromatography, Sephadex LH-20 column chromatography and preparative HPLC. Its structure was determined as 4,6-dihydroxy-2-p-hydroxyphenyl-isoindol-1-one on the basis of the UV, NMR, and MS spectroscopic analysis. The compound 1 showed potent free radical scavenging activity against superoxide, ABTS, and DPPH radicals, and protective effect against cellular DNA damage induced by oxidative stress.