Wirgiliusz Duda

Damage of erythrocyte by phenoxyacetic herbicides and their metabolites

The molecular background of toxic properties of phenoxy herbicides for humand and animals is insufficiently studied. In this study, damage parameters (hemolysis, hemoglobin oxidation, and lipid peroxidation) were measured in human erythrocytes exposed to several commonly used herbicides from this group (2,4-D, 2,4,5-T, and MCPA) and their phenolic metabolites. For all parameters studied the impact of herbicide metabolites was stronger than that of herbicides themselves. The extent of hemolysis was dose-dependent and also depended on the solvent used. Whereas compounds with methyl groups were more potent in the methemoglobin formation assay, compounds with chlorine substituents caused higher lipid peroxidation.

CATALASE ACTIVITY IN HUMAN ERYTHROCYTES: EFFECT OF PHENOXYHERBICIDES AND THEIR METABOLITES

The effects of exposure to different concentrations of phenoxyherbicides and their metabolites were studied in human erythrocytes, with particular attention to catalase (CAT—EC. 1.11.1.6— hydrogen peroxide: hydrogen peroxide oxidoreductase). 4‐chloro‐2‐methylphenoxyacetic acid (MCPA), 2,4‐dimethylphenol (2,4‐DMP) and 2,4‐dichlorophenoxyacetic acid (2,4‐D) did not affect CAT activity, but 2,4‐dichlorophenol (2,4‐DCP) and 2,4,5‐trichlorophenol (2,4,5‐TCP) decrease its activity, the latter being the more inhibitory.

Influence of phenoxyherbicides and their metabolities on the form of oxy‐and deoxyhemoglobin of vertebrates

The effect of phenoxyherbicides and their metabolites on the structure of oxy‐ and deoxyhemoglobin was studied by using different doses and times of incubation of hemoglobin with the herbicide. It was ascertained that among the investigated hemoglobins the most sensitive was carp oxyhemoglobin incubated with 2,4‐D (2,4‐dichlorophenoxyacetic acid) and the least sensitive was human hemoglobin. Comparing the toxicity of 2,4‐D, MCPA (2‐methyl‐4‐chlorophenoxyacetic acid), 2,4‐DCP (2,4‐dichlorophenol), 2,4‐DMP (2,4‐dimethylphenol) it was found that the highest decrease occurred in bovine hemoglobin incubated with 2,4‐DMP. The phenoxyherbicides caused stabilization of the structure of T‐deoxyhemoglobin in vitro, in that they decreased the oxygen affinity with a simultaneous increase in methemoglobin concentration.

Chlorophenols induce lipid peroxidation and change antioxidant parameters in the leaves of wheat (Triticum aestivum L.)

In this work, changes in superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (POD) activity were determined in the leaves of wheat (Triticum aestivum L.) exposed to 2,4-dichlorophenol (2,4-DCP) and pentachlorophenol (PCP). We analyzed the content of free phenols, the level of lipid peroxidation, and also the oxidation of dihydrorhodamine 123 by 2,4-DCP and PCP. Chlorophenols were spiked to soil in concentrations of 0.5 and 5.0 mg kg(-1). Plant seeds were raised in plastic pots containing soil at a temperature of 25 degrees C with a 16-h photoperiod and irradiance of 250 micromol m(-2) s(-1). The leaves were harvested on the third, sixth and twelfth days of the experiment. The inhibition of SOD activity in the leaves of wheat was observed for 2,4-DCP and PCP. 2,4-DCP and PCP induced changes in CAT activity with a stronger effect for PCP. The compounds markedly increased guaiacol POD activity during 12d of the exposition of wheat to their action. The increase in free phenol content was observed both for 2,4-DCP and PCP. Chlorophenols also induced a powerful lipid peroxidation process between the third and sixth days of the experiment. A higher concentration of chlorophenols used in our study induced greater changes in all of the investigated parameters. 2,4-DCP and PCP oxidized the fluorescent probe - dihydrorhodamine 123 - in the concentrations of 5 and 1 ppm, respectively, and the addition of magnesium ions enhanced the oxidative capacity of the examined xenobiotics.

Comparison of the effect of Aminopielik D pesticide and its active components on human erythrocytes.

In the present work, the effect of Aminopielik D [417.5g/l of dimethylamino salts of 2,4-dichlorophenoxyacetic acid (2,4-D) and 32.5g/l of 3,6-dichloro-2-metoxybenzoic acid (Dicamba)] and its active components (used separately and in mixture) on human erythrocytes was examined. The parameters studied were: lipid peroxidation, metHb formation and catalase activity. Aminopielik D used at doses of 100-1000ppm was found to increase lipid peroxidation, decrease of catalase activity and oxidation of haemoglobin. 2,4-D and Dicamba are present in Aminopielik D in the dimethylamino form; their sodium salts in solution (separately and as a mixture) did not cause such strong effects. A synergistic action of 2,4-D and Dicamba was excluded as the individual compounds caused the same effects as their mixture. Aminopielik D provoked slightly higher changes in the lipid peroxidation and catalase activity than its active components alone and in mixture, which was probably a result of the properties of the additives and interaction of tested systems with the dimethylamino group.

The effect of alendronate sodium on human erythrocytes

Alendronate sodium is a medicine, which is commonly used in osteoporosis treatment. Nowadays, this substance is given to patients in tablets, but in future it is planned that it will be administrated into human organisms as intravenous infusions; therefore, significant interactions of this medicine with erythrocytes will be inevitable. It is the reason why we decided to investigate the interaction of alendronate sodium with human erythrocytes. The effect of this medicine on acetylcholinesterase activity, lipid and protein peroxidation, as well as cellular thiol content was examined. Moreover, the effect of alendronate sodium on alterations in erythrocytes morphology was assessed. Human erythrocytes were incubated with alendronate sodium in the concentrations ranging from 0.33 to 100 μM for 1 h and 24 h. No changes have been observed in the parameters examined after 1h of incubation of the erythrocytes with this medicine excluding the carbonyl groups level. Moreover, no alterations in the activity of acetylcholinesterase, the level of thiols as well as in morphology of the erythrocytes incubated with alendronate sodium for 24h have been observed. It was also proven that alendronate sodium increased the level of reactive oxygen species (ROS) but only after 24h of incubation. We have not observed any severe changes in cells studied even at the highest dose of bisphosphonates examined, thus their usage should not be dangerous for the erythrocytes of people treated with these medicines.