RESUMEN
In this study, the protective role of Urtica dioica extract (Udex) against Li2CO3 toxicity in Allium cepa L. was investigated using various parameters such as germination rates, root growth, weight gain, mitotic index (MI), malondialdehyde (MDA), micronucleus (MN), antioxidant enzyme activity, chromosomal abnormalities (CAs) and anatomical changes. As the biological activity of Udex is related to its active content, the profile of phenolic compounds was determined by LC-MS/MS analysis. Li2CO3 caused abnormalities in the tested parameters and serious regressions in germination parameters. Application of 100 mg/L Li2CO3 reduced the chlorophyll a and b contents by 73.04% and 65.7%, respectively. Li2CO3 application exhibited a cytotoxic effect by inducing significant decreases in MI and increases in the frequency of MN, and also showed a genotoxic effect by causing CAs. After 100 mg/L Li2CO3 treatment, MDA, proline, superoxide dismutase, and catalase levels increased by 54.9%, 58.5%, 47.8%, and 52.3%, respectively. Li2CO3 and Udex co-administration resulted in a regression in increased biochemical parameters and genotoxicity parameters, and an improvement in germination parameters. Furthermore, Udex demonstrated efficacy in mitigating the detrimental effects of Li2CO3 on the root tip, particularly in the 200 µg/mL Udex-treated group. The thickening of the cortex cell wall and conduction tissue, which is commonly induced by Li2CO3, was not observed in the Udex-treated group. The protective effect of Udex can be explained by the phenolic compounds it contains. Rutin was detected as the major component in Udex and other phenolics were listed according to their presence rate as protecatechuic acid > caffeic acid > p-coumaric acid > syringic acid > rosemarinic acid > epicatechin. Li ions, which increase in the environment after industrialization, are an important environmental pollutant and exhibit toxicity that affects many pathways in organisms. Scientific research should not only detect these toxic effects but also develop solutions to such problems. In this study, it was determined that the Udex application had a toxicity-reducing role against Li2CO3 toxicity. Also, it has been demonstrated that A. cepa is an important indicator in determining this toxicity and toxicity-reducing applications.