Determination of the Effective Dose of Curcumin alone and in Combination with Antimicrobial Peptide CM11 on Promastigote Forms of Iranian Strain of L. major (MRHO / IR / 75 / ER).

Zoonotic cutaneous leishmaniasis t caused by Leishmania major is spread in focal areas of more than 90 countries in the tropics, subtropics, and southern Europe. In the absence of any effective vaccine, the only means to treat and control leishmaniasis is conventional medication. Glucantime is the first choice of anti-leishmanialdrug, has serious side effects like high toxicity, exorbitant cost, problems with the administration and development of resistance. Curcumin is the active component from the rhizome of herb Curcuma longa, possessing many pharmacological and biological activities with antiprotozoal and anti-proliferative effects which make it a good alternative to existing therapy. Antimicrobial peptides like CM11, a small peptide consisting of 11 amino acids, are also novel potential drugs against at least wide spectrum of microbial organisms. The aim of this study was to evaluate the effect of curcumin alone and in combination with CM11 on promastigote form of L. major (MRHO / IR / 75 / ER) for 12h and 24h in vitro. The results of Giemsa staining showed that the morphology of the flagellum and cell shape increased changed with increasing concentration of curcumin (5 µM, 10 μM, 20 μM, 40 μM and 80 μM). MTT and Trypan blue results demonstrated that the promastigotes were susceptible against curcumin in dose and time dependent manner, while CM11 alone at concentration of 8 µM as well as in combination with 10 and 20 µM curcumin had no significant effect on promastigotes. Our results revealed that curcumin can provide a new curative candidate against cutaneous leishmaniasis.