Diketopiperazines from fermentations: metabolites, artifacts, or both

Lahorenoic acids A-C, ortho-dialkyl-substituted aromatic acids from the biocontrol strain Pseudomonas aurantiaca PB-St2

Three new aromatic acids, named lahorenoic acids A (1), B (2), and C (3), have been isolated along with the known compounds phenazine-1-carboxylic acid (4), 2-hydroxyphenazine-1-carboxylic acid (5), 2-hydroxyphenazine (6), 2,8-dihydroxyphenazine (7), cyclo-Pro-Tyr (8), cyclo-Pro-Val (9), cyclo-Pro-Met (10), and WLIP (11) and characterized from the biocontrol strain Pseudomonas aurantiaca PB-St2. The structures of these compounds were deduced by 1D and 2D NMR spectroscopic and mass spectral data interpretation. Compounds 2, 4, and 7 showed moderate antibacterial activity against mycobacteria and other Gram-positive bacteria, while 4 was also found to exhibit cytotoxic and antifungal properties.

Identification of a urinary metabolite of perazine as a piperazine-2,5-dione derivative

A non-basic perazine metabolite has been isolated from the urine of schizophrenic patients ingesting perazine. Identification of this compound as 10-[3‘-(2“,5”-dioxo-4“-methyl-piperazinyl)-propyl]-phenothiazine sulphoxide was achieved using ultraviolet, infrared, nuclear magnetic resonance and mass spectroscopy.