The assessment of the environmental hazard of isomers of 1,2,4-triazole phenolic derivatives for natural ecosystems

It’s necessary to synthesize homologues of compounds frequently used in practice and to analyze their biological activity in laboratory experiments using screening tests that provide an integral assessment of biological responses to assess the effect of anthropogenic xenobiotics with different structures on ecosystems adjacent to agricultural complexes. We analyzed alcohol solutions of 2-(1H-1,2,4-triazolyl-methyl)phenol (ortho-isomer) and 4-(1H-1,2,4-triazolyl-methyl)phenol (para-isomer) in three concentrations: 0,0001; 0,001; 0.01 mg/ml using the Allium-test. The solvent was 0,1% isopropyl alcohol; the test object was Allium fistulosum L. The duration of the experiment was 5 days. Triazolide solutions significantly inhibited seed germination at all investigated concentrations. However, no significant differences were found between the isomers and the studied concentrations. Both isomers inhibited root growth at all concentrations tested. The toxicity of a triazolide containing an OH group in the para-position didn’t change over the selected concentration range. For its ortho-isomer, toxicity increased with increasing concentration, reaching the toxicity of its homologue at a dose of 0,01 mg/ml. Both tested compounds significantly inhibited the proliferation of meristem cells as compared to the control. At the same time, no differences were observed in the effect of homologues with the OH-group in the para- and ortho-position on the value of the mitotic index. However, we found a paradoxical reaction: both homologues showed maximum cytotoxicity at a minimum concentration of 0,0001 mg/ml, and cytotoxicity decreased with increasing concentration compared to control. A triazolid containing an OH group in the para-position caused a block at the metaphase and anaphase stages at the lowest concentration. The specificity of its action disappeared with an increase in concentration, which was expressed in a general prophase and metaphase block. Its ortho-isomer inhibited cell division at all concentrations at the prophase stage. Both compounds are mutagenic. The number of chromosomal aberrations depended on both the structure of the compounds and their concentration. The para-homologue is less mutagenic than ortho. In the ortho-homologue, mutagenicity decreased slightly with increasing concentration. The highest mutagenicity was found for the ortho-homologue at its lowest concentration. The paper discusses possible mechanisms of action of isomers and their negative impact on plant organisms in ecosystems.