Isolation of a New Natural Quinone, 2-Hydroxy-6-methoxy-3,5-dimethyl- 1,4-benzoquinone, from the Potato Culture Solution of Phoma wasabiae Yokogi

Previously, flaviolin was isolated from the blackish culture solution oi Phoma wasabiae [1]. In continuation of the study on the metabolites of this mold, we have now isolated 2-hydroxy-6-methoxy3,5-dimethyl-l,4-benzoquinone. This benzoquinone was already synthesized [2], but has not been found as a natural product. In this paper we wish to report on the isolation of the above quinone from the blackish culture solution. Phoma wasabiae was cultivated on the potato culture solution containing 20% glucose at 25 °C for 3 or 4 weeks. After 3 or 4 weeks of the cultivation, the blackish culture solution was filtered and a 20% solution of lead acetate added at the ratio of 3 ml to 100 ml of the blackish culture solution to precipitate some dark brown substances. After centrifuging, the supernatant solution was concentrated and centrifuged again. The aqueous layer was acidified with sulfuric acid to remove lead sulfate and filtered. The filtrate was extracted 3 times with ether of the same volume as the aqueous solution. The residue showed five yellow bands (Rf values 0.2, 0.4, 0.5, 0.7 and 0.9) and one purple band (Rf value 0.6) on a silica-gel plate (E. Merck,