Tubermycin B (1-phenazinecarboxylic acid) is a simple phenazine produced by several species of Pseudomonas and Actinomycetes. Tubermycin B is a weakly active antibacterial compound that plays a role in the biocontrol of plant diseases by several Pseudomonas strains. Tubermycin B and related phenazines are important dereplication standards in discovery research to eliminate leads due to high amounts of weakly potent actives.