New metabolites of Fusarium martii related to dihydrofusarubin.

Six strains of Fusarium martii produced fusarubin and dihydrofusarubins A and B. Further examination of strains, T-77 and T-127, showed that four additional metabolites were produced. By 1H and 13C NMR spectral analyses, these additional metabolites have been identified as 3-O-methyl and 3-O-ethyl ethers of fusarubin and dihydrofusarubin A. The methyl ethers are new compounds and showed moderate cytostatic activity against mouse leukemia L1210 culture cells as well as moderate antibiotic activity against Gram-positive bacteria and fungi. 3-O-Methyl and 3-O-ethyl ethers of dihydrofusarubin A were converted non-enzymically to the respective ethers of fusarubin under alkaline conditions. Since in addition, only dihydrofusarubin derivatives were formed when an acidic pH was maintained in the culture, it can be concluded that only these are true metabolites of Fusarium martii.