Genotoxicity mechanism of food preservative propionic acid in the in vivo Drosophila model: gut damage, oxidative stress, cellular immune response and DNA damage

Propionic acid is a short-chain fatty acid that is the main fermentation product of the enteric microbiome. It is found naturally and added to foods as a preservative and evaluated by health authorities as safe for use in foods. However, propionic acid has been reported in the literature to be associated with both health and disease. The purpose of this work is to better understand how propionic acid affects Drosophila melanogaster by examining some of the effects of this compound on the D. melanogaster hemocytes. D. melanogaster was chosen as a suitable in vivo model to detect potential risks of propionic acid (at five concentrations ranging from 0.1 to 10 mM) used as a food preservative. Toxicity, cellular immune response, intracellular oxidative stress (reactive oxygen species, ROS), gut damage, and DNA damage (via Comet assay) were the end-points evaluated. Significant genotoxic effects were detected in selected cell targets in a concentration dependent manner, especially at two highest concentrations (5 and 10 mM) of propionic acid. This study is the first study reporting genotoxicity data in the hemocytes of Drosophila larvae, emphasizing the importance of D. melanogaster as a model organism in investigating the different biological effects caused by the ingested food preservative product.