Cytotoxicity of myriocin against axenic culture of Leishmania mexicana

Serine Palmitoyltransferase SPT is the key enzyme in the de novo sphingolipids biosynthesis pathway in eukaryotes, including the intracellular parasite Leishmania. Previous studies showed that this enzyme SPT is expressed only in divided promastigote forms and it is non-essential in the amastigotes form of Leishmania major, which is known as the old world leishmaniasis. In this study we have studied the viability of new world lesihamniasis, Leishmania mexicana. Cytotoxicity test used to determine the effect of the SPT inhibitor myriocin which did not significantly affect the viability of the two forms of the in vitro cultures of the parasite p<0.05, procyclic promastigotes and amastigotes, in which cell viability for miltefosine treatment 100, 50, 25, 12.5, 6.25µM against procyclic promastigotes form was 133.7, 115.8, 103.7, 94.98, 94.78 respectively for 24 hours incubation, while for amastigotes, cell viability for miltefosine treatment was 114.77, 114.34, 104.21, 132.95, 102.74 respectively for the 24 hours incubation and was 81.46, 81.25, 71.40, 68.38, 66.51 respectively for the 48 hours incubation and was 78.99, 90.22, 85.59, 95.18, 84.43 respectively for the 72 hours incubation. While in the old world leishmaniasis, Leishmania major, it has been found that ceramide production is absent and non-essential for the proliferation of intra-amastigotes.