2 OXAZOLYL COMPOUNDS AND A MONOSUBSTITUTED ALPHA-PYRONE AS FREE-RADICAL SCAVENGERS ISOLATED FROM A FUNGUS

In the course of our screening for free radical scavengers, (1'E)-eryt hro-4-(3',4'-dihydroxypentenyl)oxazole (1) (1'E,4'S)-4-(3'-oxo-4'-hydr oxypentenyl)oxazole (2) and 6-pentyl-alpha-pyrone (3) were isolated fr om an unidentified fungal metabolite. These compounds, especially nove l oxazolyl compound 2, inhibited the bactericidal effect of the Fenton reagent toward Bacillus subtilis. They and their acetylated compounds (diAc-1 and Ac-2) also showed inhibitory activity against linoleate a utoxidation. Furthermore, 1-3 inhibited oxidative enzymes (soybean lip oxygenase and mushroom tyrosinase). To investigate the radical scaveng ing mechanism of 3, two oxidized products (4 and 5) were isolated from the reaction mixture of 3 and the Fenton reagent. Compounds 4 and 5 s eemed to be derived from 3 by scavenging the hydroxyl radical.