Bisphosphonate-based molecules as potential new antiparasitic drugs
Leishmaniasis; Leishmania amazonensis; Bisphosphonates; Farnesyl diphosphate synthase; Antiparasitic Drugs.
Leishmaniasis is one of the main neglected tropical diseases caused by several species of parasite of the genus Leishmania responsible for at least twelve million cases of infections worldwide. Despite its importance in terms of public health, treatment of patients is limited and has mainly low levels of efficacy and safety. Bisphosphonates are compounds that inhibit the enzyme farnesyl diphosphate synthase (FPPS) that acts in the initial stages of ergosterol synthesis that maintains the integrity of the lipid bilayer of the disease-causing parasite. In this sense, the central objective of this project is to evaluate the antiparasitic activity of synthetic compounds based on bisphosphonates in Leishmania amazonensis. Twenty-four compounds covering a concentration range of 100μM to 1μM were evaluated against L. amazonensis promastigotes for a period of 24 hours through the colorimetric assay of resazurin, and those that obtained inhibition greater than 50% of the initial concentration were selected to determine values IC50. In addition, the molecular docking was evaluated against the FPPS enzyme of L. amazonensis and the possible mechanisms of the antiparasitic activity of these compounds. Parasitic screening showed a significant reduction in the highest concentration in compounds 1656 and 1662, with inhibition values of 100% (IC50 = 58.39 μM) and 88% (IC50 = 52.86 μM), respectively. Moderate activity for 1651 (40%) and 1652 (42%). The other compounds showed inhibition below 40%. In molecular docking, compounds 1656 and 1662 interacted with the FPPS enzyme by bonding with hydrogen bonds. And in the double fixation assay by Appendix V-FITC and PI, compound 1662 showed apoptosis at concentrations of 100 μM (3.84%) and 50 μM (1.75%) and necrosis at 100 μM (17.7%) and 50 μM (12.4%). Only compound 1656 presented necrosis with values of 2.70 and 2.73%, in the same concentration sequence. These results show that synthetic compounds based on bisphosphonates have been shown to be potential candidates for leishmaniasis chemotherapy. Since the main measures to control this disease are through therapeutic treatment programs, this project encourages further studies to identify active compound (s) for the control of leishmaniasis.