Genotoxicity of the herbicides alachlor and maleic hydrazide in cultured human lymphocytes

Abstract

The herbicides alachlor and maleic hydrazide were evaluated for genotoxicity in peripheral blood human lymphocyte cultures. Sister-chromatid exchanges (SCE), chromosome aberrations (CA) and micronuclei (MN) were scored as genetic endpoints. To detect possible metabolic modifications in the genotoxicity of both herbicides, the cultures for SCE and MN demonstration were also treated with S9 fraction. From our results we conclude that, in the absence of metabolic activation, the two herbicides induce significant increases in the frequency of SCE, although the concentrations needed to be effective are very different. Thus, alachlor gave positive results at concentrations ranging from 1 microg/ml, and maleic hydrazide at concentrations ranging from 100 microg/ml. In addition, alachlor appears to be clastogenic in both the CA and MN assays, but only at the highest concentration tested (20 microg/ml). The co-treatment with the S9 fraction produced a slight decrease in the induction of SCE with both herbicides: nevertheless, it does not seem to affect the response in the MN assay.

Use of the Drosophila wing spot test in the genotoxicity testing of different herbicides

“…Nevertheless, this frequency decreased drastically in the balancer heterozygous wings, indicating that this herbicide mainly induces mitotic recombination. These results confirm previous data from our group indicating that this chemical is genotoxic in Drosophila [Torres et al, 1992] and in human peripheral blood lymphocytes [Ribas et al, 1996]. In addition, maleic hydrazide has been reported as an efficient genotoxic agent in plants [Swietlinska and Zuk, 1978;Xiao and Ichikawa, 1995] but conflicting results were obtained in animal cells [Meschini et al, 1988].…”

“…In this context, our findings, which show that in the HB cross the frequency of mutant clones is clearly reduced with respect to the response obtained in the ST cross, are of interest, because they support the hypothesis that the genotoxicity of maleic hydrazide is mediated by its biotransformation. In fact, in cultured human lymphocytes it has been shown that the addition of S9 reduced the frequency of sister-chromatid exchanges [Ribas et al, 1996].…”

Presence of Dichlorodiphenyltrichloroethane (DDT) in Croatia and Evaluation of Its Genotoxicity

“…Pesticides tend to be very reactive compounds that can form covalent bonds with various nucleophilic centers of cellular biomolecules, including DNA (Crosby, 1982). For instance, the induction of DNA damage can potentially lead to adverse reproductive outcomes, the induction of cancer and many other chronic diseases (Ribas et al, 1996;Lander et al, 2000;Meinert et al, 2000;Ji et al, 2001). A great variety of tests and test systems based on microbes, plant and animals have been developed in order to asses the genotoxic effects of xenobiotic agents, including pesticides.…”

Onions, Shallots and Garlic

“…In Germany, however, its use is not permitted. The use of MH in foodstuffs has been questioned as studies have shown links between MH and the production of tumours in mammals (Ribas et al 1996). It has been estimated that the average adult ingests approximately 630 mg of MH a day from potatoes, onions and tobacco from cigarette smoke (USEPA 1999).…”