Pyrrolnitrin (hereinafter referred to as PN) is a new antifungal antibiotic, recently isolated from Pseudomonas pyrrocinia n. sp. by Arima et al¹⁾., and the chemical structure of this substance is established as follows : ¹⁾

The above chemical structure was confirmed synthetically by this laboratories²⁾.

Comprehensive studies of PN were undertaken to observe its antimicrobial activity in vitro, its distribution in the body and excretion after oral administration, its therapeutic activity on animals with experimentally-induced fungal infection and its toxicity.

The antifungal activities of PN were compared with those of other widely used antifungal agents.