Evaluation of the Effects of Ephedrine on Human Lymphocytes in the Comet Assay

Ephedrine, a natural alkaloid from plants of the genus Ephedra, has a chemical structure similar to catecholamines. It is well established that catecholamines (adraneline, noradrenaline and dopamine) cause genotoxic and mutagenic effects. Therefore, the objectives of this investigation were to examine weather ephedrine can exhibit genotoxic effects on isolated human lymphocytes in the Comet assay. Dose-response of human lymphocytes was determined at the concentration range of ephedrine from 0.0005 μM to 500 μM. Three concentrations of ephedrine (1, 50 and 300 μM) which had acceptable cell viability (over 90%) were used for further experiments with inhibitors of DNA reparation (cytosine arabinoside and hydroxyurea). The obtained results showed that ephedrine did not induce DNA damage in isolated human lymphocytes. However, co-treatment of the negative control with DNA repair inhibitors caused a slight but significant increase of DNA damage, due to an endogenous DNA damage. Interestingly, cells treated with ephedrine and DNA repair inhibitors did not express increased DNA damage. On the basis of the obtained results it can be concluded that ephedrine did not exhibit genotoxic effects on isolated human lymphocytes. This result is in accordance with previous investigations showing negative genotoxicological results for ephedrine using bacterial gene mutation test-systems and in vitro cytogenetic analysis.