Ochratoxin B (OTB), a secondary metabolite of Aspergillus ochraceus, is the nonchlorinated analogue of the mycotoxin ochratoxin A (OTA), which is one of the most potent renal carcinogens in rodents [1].
Intracellular concentration of Ochratoxin B following 24-h incubation with a noncytotoxic dose (10 µM) was 2.2 ± 0.25 pmol/ml of cell lysate for Ochratoxin B [1]. Based on fluorescence studies, Ochratoxin B form highly stable complexes with Human serum albumin (HSA) [2].
The rats given ochratoxin B or ochratoxins A and B (4mg/kg) were clinically unaffected, while the rats given ochratoxin A (4mg/kg) reduced food intake by 50%, and they lost ca. 10% of their weight during the experimental period [3]. Both single (10 mg/kg, oral) and repeated (2 mg/kg 2 weeks, oral) administration of ochratoxin B do not induce pronounced adverse effects in rats as indicated by only minor histopathologic changes in the kidney after a single high dose and absence of histopathology in the kidney and the liver after repeated administration [1].
References:
[1]. Mally A, Keim-Heusler H, Amberg A, et al. Biotransformation and nephrotoxicity of ochratoxin B in rats[J]. Toxicology and applied pharmacology, 2005, 206(1): 43-53.
[2]. Faisal Z, VÖrÖs V, FliszÁr-NyÚl E, et al. Probing the interactions of ochratoxin B, ochratoxin C, patulin, deoxynivalenol, and T-2 toxin with human serum albumin[J]. Toxins, 2020, 12(6): 392.
[3]. StØrmer F C, Kolsaker P, Holm H, et al. Metabolism of ochratoxin B and its possible effects upon the metabolism and toxicity of ochratoxin A in rats[J]. Applied and environmental microbiology, 1985, 49(5): 1108-1112.