Detoxifying and anti-oxidant enzymes of Fasciola gigantica worms under triclabendazole sulphoxide (TCBZ-SX): an in vitro study.

Triclabendazole (TCBZ) is an efficient fasciolicide that affects both juvenile and adult worms. After oral administration it is rapidly metabolized to TCBZ sulphoxide and sulphone that were found responsible for its fasciolicidal activity. Parasite defense mechanisms include detoxifying and anti-oxidant enzymes that would suppress its oxidative killing. The present work aimed at evaluating these enzymes under TCBZ-SX. Thirty juvenile and 30 adult F. gigantica worms collected from the liver parenchyma and bile ducts formed the subject of the study. Levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), and glutathione (GSH) were measured in juvenile and adult worms incubated, without and with 15 and 50 microg/ml TCBZ-SX for 18 hours at 37 degrees C. Results demonstrated a significant decrease in SOD activity and an increase in GST level in both juvenile and adult worms after incubation in the two concentrations. The remaining enzymes and GSH revealed variable levels.