Synthesis and comparison of anti-Leishmania major activity of antimony and iron complexes of 3-hydroxypyran-4-one and 3-hydroxypyridine-4-one as bi-dentate ligands

Background: Leishmaniasis infection threatens millions of people in under developing and developing countries. Treatment of this neglected disease is very complicated. Subjects and Methods: A novel series of antimony (V) complexes using bidentate ligands of hydroxypyranones and hydroxypyridinones have been designed and synthesized. For the synthesis of the complexes, SbCl5 in water was added to the solution of each ligand at 60°C and the pH of mixture was adjusted to 8 using aqueous NaOH. After 24 h stirring, extraction of produced compound into acetone gave the desired complex. The structure of complexes was achieved by using FTIR, 1HNMR, and electron spin ionization mass spectroscopic techniques. All compounds were evaluated for in vitro anti amastogote form of Leishmania major. Results and Conclusion: The most potent antimony complexes against amastigotes were 5b (after 48 and 72 h) and 5a (after 72 h) with IC50 values of 24.4, 16.3, and 30.1 µg/mL, respectively. Furthermore, antimony and iron complexes were used together for in vitro anti amastigote form of L. major activity. These compounds were toxic for macrophages and destroyed them.