Isolation and structure determination of phenazostatin D, a new phenazine from a marine actinomycete isolate Pseudonocardia sp B6273

A new phenazine derivative, phenazostatin D (1a), was isolated from an extract of the actinomycete isolate Pseudonocardia sp. B6273 via a TLC-guided chemical screening. The structure of the compound was assigned by spectroscopic methods and found to be the meso-form of phenazostatin B (1b). Phenazostatin D was inactive against the tested bacteria and fungi. The strain also produced the known phenazine antibiotic methyl saphenate (2).