**2. The role of the antioxidant system in** *Leishmania*

Leishmaniasis is caused by the protozoan flagellate *Leishmania* which is transmitted by sand‐ flies of the genus *Phlebotomus* (Sharma and Singh, 2008). There are several species of the ge‐ nus *Leishmania* which are known to cause this infectious disease. Leishmaniasis shows a broad spectrum of clinical manifestations and includes visceral, cutaneous and mucocutane‐ ous leishmaniasis. Whereas the two latter ones are not considered to be lethal (Herwaldt, 1999), infection with *Leishmania donovani/infantum* – resulting in kala azar or visceral leish‐ maniasis - can be lethal without treatment. Although treatment of leishmaniasis with che‐ motherapeutics is the only current option, drug resistance to first-line drugs is increasing which is accompanied by frequently occurring toxic side effects and by the high cost of treatment (Van Assche et al., 2011). Additionally, the small number of novel drugs com‐ bined with the low number of identified and subsequently validated number of *Leishmania* drug targets in clinical use, reveals an alarming situation for the current status in chemother‐ apy. The predominant target for the application of chemotherapy is the amastigote stage which proliferates intracellularly in tissue macrophages (Dedet et al., 2009), thereby hinder‐ ing the accessibility of antileishmanial drugs to the pathogen.
