**4.2 Mechanism of action**

Leishmania amastigote converts the pentavalent form of SSG to a toxic trivalent form by a specific reductase enzyme. This in turn promotes the efflux of glutathione and reduced thiols within the parasite and increases oxidative damage. Other action includes inhibition of glycolysis and oxidation of fatty acids of the parasite. Accumulation of SSG within macrophages is responsible for its prolonged inhibitory action against the parasite.
