Toxoplasma gondii: Effects of Artemisia annua L. on susceptibility to infection in experimental models in vitro and in vivo

Considering that the treatment for toxoplasmosis is based on drugs that show limited efficacy due to their substantial side effects, the purpose of the present study was to evaluate the effects of Artemisia annua on in vitro and in vivo Toxoplasma gondii infection. A. annua infusion was prepared from dried herb and tested in human foreskin fibroblasts (HFF) or mice that were infected with the parasite and compared with sulfadiazine treatment. For in vitro experiments, treatment was done on parasite before HFF infection or on cells previously infected with T gondii and the inhibitory concentration (IC50) values for each treatment condition were determined. Viability of HFF cells in the presence of different concentrations of A. annua infusion and sulfadiazine was above 72%, even when the highest concentrations from both treatments were tested. Also, the treatment of T. gondii tachyzoites with A. annua infusion before infection in HFF cells showed a dose-response inhibitory curve that reached up to 75% of inhibition, similarly to the results observed when parasites were treated with sulfadiazine. In vivo experiments with a cystogenic T. gondii strain demonstrated an effective control of infection using A. annua infusion. In conclusion, our results indicate that A. annua infusion is useful to control T gondii infection, due to its low toxicity and its inhibitory action directly against the parasite, resulting in a well tolerated therapeutic tool. (C) 2009 Elsevier Inc. All rights reserved.