Toxicological Evaluation of Occidiofungin against Mice and Human Cancer Cell Lines

Occidiofungin, a glyco-lipopeptide obtained from the liquid culture of Burkholderia contaminans MS14, has been identified as a novel fungicide. The natural product was shown to have a minimal amount of toxicity in a previous mouse toxicity study following intraperitoneal and subcutaneous administration. In this study, the toxicity of occidiofungin was evaluated following a 5 mg/kg intravenous tail vein injection. In addition, the toxicity of occidiofungin was evaluated against human fibroblast and cancer cell lines. Weight loss was the most significant observation following intravenous administration of occidiofungin. Histology, hematology, and blood serum chemistry did not reveal any significant signs of toxicity. The activity observed in the in vitro cytotoxicity assay against the cancer cell lines was all below 75 nM concentration of occidiofungin. To date, the potency of occidiofungin against these cancer cell lines is greater than any activity observed against fungi. The findings in this study support the need to further evaluate occidiofungin’s chemotherapeutic potential.