Genotoxicity of a synthetic plant growth regulator, Forchlorfenuron (CPPU), on human lymphocytes using chromosome aberration assay

Forchlorfenuron (FCF, also known as CPPU), which belongs to the group of phenylurea cytokinins, is one of the most widely used synthetic plant growth regulators (PGRs) worldwide. Although FCF plays a crucial role in cellular growth and differentiation by promoting cell division in plants, it disrupts higher-order septin assembly in other eukaryotic organisms, including humans. Despite its widespread use, no study has been found investigating the genotoxic effects of this synthetic PGR on humans. Hence, this investigation was designed to examine the potential cyto-genotoxicity of a commercial formulation of FCF on human peripheral blood lymphocytes (PBLs) using chromosome aberrations (CAs) and mitotic index (MI) endpoints. The whole blood cultures were treated with 0.25, 0.50, 1.00, and 2.00 µg/ml concentrations of a commercial form of FCF. According to the results, FCF significantly enhanced the percentage of cells containing structural CAs at the concentrations of 1.00 and 2.00 µg/ml for both treatment times (24 and 48 h), in comparison to the negative control (P<0.05). Besides, in cultures exposed to FCF concentrations of 0.50, 1.00, and 2.00 µg/ml, the total CA/cell ratio was significantly higher (P<0.05). In addition, FCF was found to have cytotoxic activity on human PBLs at all treatments (except for the lowest concentration at 24 h) by significantly reducing the MI compared to the negative control (P<0.05). The findings of this investigation indicate the first time that a commercial formulation of FCF (0.50-2.00 µg/ml) may have genotoxic and cytotoxic potential on human lymphocytes.