Evaluation of the effects of ephedrine on human lymphocytes in the comet assay

Abstract

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.

Efedrin, prirodni alkaloid iz biljaka roda Ephedra, ima sličnu hemijsku strukturu sa kateholaminima. Dobro je poznato da kateholamini (adrenalin, noradrenalin i dopamin) mogu da prouzrokuju genotoksične i mutagene efekte. Stoga su ciljevi ovog istraživanja bili da se ispita da li efedrin može da ispolji genotoksične efekte na izolovanim limfocitima čoveka u Komet testu. Odnos doza-efekat određ en je u rasponu koncentracija efedrina od 0.0005 μM do 500 μM. Tri koncentracije efedrina (1, 50 and 300 μM) koje su imale prihvatljiv nivo ćelijske vijabilnosti (preko 90%) upotrebljene su za dalje eksperimente sa inhibitorima reparacije DNK (citozin arabinozid i hidroksiurea). Dobijeni rezultati pokazuju da efedrin nije indukovao oštećenja DNK na izolovanim limfocitima čoveka. Međutim, istovremeni tretman sa inhibitorima reparacije DNK doveo je do malog ali statistički značajnog porasta oštećenja DNK kod negativne kontrole, usled endogenog oštećenja DNK. Interestantno je da ćelije tretirane sa efedrinom i inhibitorima reparacije DNK nisu ispoljile povećan nivo oštećenja DNK. Na osnovu dobijenih rezultata može se zaključiti da efedrin nije ispoljio genotoksične efekte na izolovanim limfocitima čoveka. Ovaj rezultat je u saglasnosti sa prethodnim istraživanjima u kojima je dokazano da efedrin ne dovodi do genotoksičnih efekata u bakterijskim testovima na genske mutacije i u in vitro citogenetičkim analizama.