Evaluation of in vitro anti-leishmanial activities of curcumin and its derivatives “gallium curcumin, indium curcumin and diacetylecurcumin”

Background: Leishmania species are intracellular parasitic hemoflagellates that infect macrophages of the skin and viscera to produce diseases in their vertebrates’ hosts. Curcumin is the active ingredient in the herbal remedy and dietary spice turmeric (curcuma longa linn). Curcumin was identified to be responsible for most of the biological effects of turmeric. Methods: Leishmania major promastigotes were cultivated in RPMI 1640 and each well of micro plate was filled with a final concentration of 4×106 parasites/ml (100μl) of culture medium and after the incubation period, the test agents including curcumin, indium curcumin (In(CUR)3), diacetylcurcumin (DAC) and gallium curcumin (Ga(CUR)3) were added. Negative control only received RPMI medium, and the positive control contained varying concentrations of standard anti-leishmanial compound, amphotericin B. MTT solution was added to each well and incubated at 25̊C for 72 hours. Afterward, isopropanol was added for solving the formazan crystals. Finally, the plates were read with an ELISA reader using 540 nm as test wavelength and 630 nm as the reference wavelength. Results: The IC50 values for curcumin, Ga(CUR)3, In(CUR)3, DAC and amphotericine B were 38μg/ml, 32μg/ml, 26μg/ml, 52μg/ml and 20μg/ml respectively. In(CUR)3 was more effective than other three test agents (IC50: 26μg/ml) and the second effective agent against leishmania was Ga(CUR)3 (IC50: 32μg/ml). Conclusion: Gallium and indium complexes of curcumin had much lower IC50 values than did their DAC analogs. Based on our study results, In(CUR)3 and Ga(CUR)3 are two important derivatives of the curcumin which need to be more evaluated as potent agents against leishmania Parasites.