Studies of the Effectiveness of Bisphosphonate and Vanadium-Bisphosphonate Compounds In Vitro against Axenic Leishmania tarentolae

Leishmaniasis is a disease that is a significant problem for people, especially in tropical regions of the world. Current drug therapies to treat the disease are expensive, not very effective, and/or of significant side effects. A series of alkyl bisphosphonate compounds and one amino bisphosphonate compound, as well as alendronate and zoledronate, were tested as potential agents against Leishmania tarentolae. Also, two polyoxometalates (POMs) with nitrogen-containing bisphosphonate ligands, vanadium/alendronate (V(5)(Ale)(2)) and vanadium/zoledronate (V(3)(Zol)(3)), were tested against L. tarentolae and compared to the results of the alendronate and zoledronate ligands alone. Of the compounds evaluated in this study, the V(5)(Ale)(2) and V(3)(Zol)(3) complexes were most effective in inhibiting the growth of L. tarentolae. The V(5)(Ale)(2) complex had a larger impact on cell growth than either alendronate or orthovanadate alone, whereas zoledronate itself has a significant effect on cell growth, which may contribute to the activity of the V(3)(Zol)(3) complex.