Journal Article

The Effect of Ursolic Acid on Leishmania (Leishmania) amazonensis Is Related to Programed Cell Death and Presents Therapeutic Potential in Experimental Cutaneous Leishmaniasis

Campos, Bruno L. S., Levy, Débora, Silva, Marcelo S., Rafael-Fernandes, Mariana, Lago, João H. G., Ribeiro, Susan P., Passero, Luiz F. D., Yamamoto, Eduardo S., Kallás, Esper G., Laurenti, Márcia D., Sessa, Deborah P., Jesus, Jéssica A., Santos-Gomes, Gabriela

2015

Overview

Among neglected tropical diseases, leishmaniasis is one of the most important ones, affecting more than 12 million people worldwide. The available treatments are not well tolerated, and present diverse side effects, justifying the search for new therapeutic compounds. In the present study, the activity of ursolic acid (UA) and oleanolic acid (OA) were assayed in experimental cutaneous leishmaniasis (in vitro and in vivo). Promastigote forms of L. amazonensis were incubated with OA and UA for 24h, and effective concentration 50% (EC50) was estimated. Ultraestructural alterations in Leishmania amazonensis promastigotes after UA treatment were evaluated by transmission electron microscopy, and the possible mode of action was assayed through Annexin V and propidium iodide staining, caspase 3/7 activity, DNA fragmentation and transmembrane mitochondrial potential. The UA potential was evaluated in intracellular amastigotes, and its therapeutic potential was evaluated in L. amazonensis infected BALB/c mice. UA eliminated L. amazonensis promastigotes with an EC50 of 6.4 μg/mL, comparable with miltefosine, while OA presented only a marginal effect on promastigote forms at 100 μg/mL. The possible mechanism by which promastigotes were eliminated by UA was programmed cell death, independent of caspase 3/7, but it was highly dependent on mitochondria activity. UA was not toxic for peritoneal macrophages from BALB/c mice, and it was able to eliminate intracellular amastigotes, associated with nitric oxide (NO) production. OA did not eliminate amastigotes nor trigger NO. L. amazonensis infected BALB/c mice submitted to UA treatment presented lesser lesion size and parasitism compared to control. This study showed, for the first time, that UA eliminate promastigote forms through a mechanism associated with programed cell death, and importantly, was effective in vivo. Therefore, UA can be considered an interesting candidate for future tests as a prototype drug for the treatment of cutaneous leishmaniasis.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Acids / Agricultural and Biological Sciences(all) / Amastigotes / Animals / Annexin V / Apoptosis / Apoptosis - drug effects / Biochemistry / Biocompatibility / Camellia / Care and treatment / Caspase / Caspase-3 / Cell death / Chemical compounds / Cutaneous leishmaniasis / Cytokines - biosynthesis / Deoxyribonucleic acid / Diadema / Disease Models, Animal / DNA / DNA fragmentation / Electron microscopy / Female / Genetics and Molecular Biology(all) / Immunology / In vivo methods and tests / Infections / Infectious diseases / Intracellular / Iodides / Laboratories / Leishmania / Leishmania - drug effects / Leishmania - ultrastructure / Leishmania amazonensis / Leishmaniasis / Leishmaniasis, Cutaneous - drug therapy / Leishmaniasis, Cutaneous - parasitology / Leishmaniasis, Cutaneous - pathology / Macrophages / Macrophages, Peritoneal - drug effects / Macrophages, Peritoneal - metabolism / Macrophages, Peritoneal - parasitology / Male / Medical schools / Medicine / Medicine(all) / Mice / Miltefosine / Mitochondria / Mitochondrial DNA / Mode of action / Mortality / Nitric oxide / Nitric Oxide - metabolism / Oleanolic acid / Oleanolic Acid - pharmacology / Parasites / Parasitic diseases / Parasitism / Pathology / Peritoneum / Pharmaceutical sciences / Pharmacology / Plant Extracts - pharmacology / Promastigotes / Propidium iodide / Protozoans / Risk factors / Side effects / Skin lesions / Transmission electron microscopy / Triterpenes - pharmacology / Trypanocidal Agents - pharmacology / Ursolic Acid / Vector-borne diseases