Amitraz and Its Metabolites: Oxidative Stress-Mediated Cytotoxicity in HepG2 Cells and Study of Their Stability and Characterization in Honey

The population decrease of bees that has been observed in recent years due to the Varroa destructor parasite may endanger the production of bee-products whose demand is on the rise. To minimize the negative effects caused by this parasite, the pesticide amitraz is commonly used by beekeepers. Based on these, the objectives of this work are to determine the toxic effects caused by amitraz and its metabolites in HepG2 cells, as well as its determination in honey samples and the study of its stability with different heat treatments commonly used in the honey industry and its relationship with the amount of 5-hydroxymethylfurfural (HMF) produced. Amitraz significantly decreased cell viability by MTT assay and total protein content (PC) assay, being more cytotoxic than its metabolites. Amitraz and its metabolites caused oxidative stress by Lipid Peroxidation (LPO) production and Reactive Oxygen Species (ROS) generation. Residues of amitraz and/or its metabolites were found in analyzed honey samples, with 2,4-Dimethylaniline (2,4-DMA) being the main metabolite confirmed by high-performance liquid chromatography-high resolution mass spectrometry (HPLC-QTOF HRMS). Amitraz and its metabolites resulted as unstable even at moderate heat treatments. Additionally, a positive correlation in terms of HMF concentration in samples and the severity of heat treatment was also observed. However, quantified amitraz and HMF were within the levels set in the regulation.

Automated summary

The decreasing bee population caused by Varroa destructor parasite poses a threat to the production of bee-products, which are in high demand. Beekeepers commonly use the pesticide amitraz to minimize the negative effects of this parasite. This study aims to determine the toxic effects of amitraz and its metabolites in HepG2 cells, analyze their presence in honey samples, investigate their stability under heat treatments in the honey industry, and explore their relationship with the production of 5-hydroxymethylfurfural (HMF). The results show that amitraz and its metabolites have significant cytotoxic and oxidative stress effects. Residues of amitraz and its main metabolite, 2,4-Dimethylaniline (2,4-DMA), were found in analyzed honey samples. Furthermore, both amitraz and HMF showed instability even under moderate heat treatments, with HMF concentration positively correlated with the severity of heat treatment.