Novel oxidized sorbicillin dimers with 1,1-diphenyl-2-picrylhydrazyl-radical scavenging activity from a fungus

Three yellowish compounds with 1,1-diphenyl-2-picryl-hydrazyl-radical scave nging activity were newly isolated from the fermentation broth of Trichoder ma sp. USF-2690 strain that had been isolated from a soil sample: two were novel oxidized sorbicillin dimers designated as bisorbicillinolide (1) and bisorbicillinolide (2), and one was sorbicillin (3) itself. The structures of 1 and 2 were determined from spectroscopic evidence. In the DPPH-radical scavenging assay, alpha-tocopherol gave an ED50 value of 17.0 mu M after s tanding for 30 min, white continuing observation showed that the ED50 value s for bisorbibutenolide, bisorbicillinolide, and sorbicillin slowly reached 80.8, 88.8 and 152.3 mu M over 24 hr.