Isolation, structural elucidation and biological properties of neoenactins B1, B2, M1 and M2, neoenactin congeners.

The structures of three neoenactin congeners, designated as neoenactins B1, B2 and M2 were elucidated by 1H and 13C NMR and mass spectroscopic studies. Another minor component, neoenactin M1, isolated from the crude mixture, was identified as lipoxamycin. All three new compounds were structurally related to neoenactin A. While B1 was proved to be a positional isomer of B2, M2 was found to be a dihydro derivative of A. All the compounds were active against yeasts and fungi and potentiated the activities of polyene antifungal antibiotics such as trichomycins A and B and amphotericin B.