Studies on new antifungal antibiotics, guanidylfungins A and B. I. Taxonomy, fermentation, isolation and characterization.

Guanidylfungin A, C58H103N3O18, and guanidylfungin B, C57H101N3O18, were isolated from the mycelia of Streptomyces hygroscopicus No. 662 by means of silica gel absorption and reversed phase liquid chromatographies. The guanidylfungins were active against fungi and Gram-negative bacteria.