Protozoan diseases, such as leishmaniasis, are a cause of considerable morbidity throughout the world, affecting millions every year. In this study, two triterpenic acids (maslinic and oleanolic acids) were isolated from Tunisian olive leaf extracts and their in vitro activity against the promastigotes stage of Leishmania (L.) infantum and Leishmania (L.) amazonensis was investigated. Maslinic acid showed the highest activity with an IC50of 9.32 ± 1.654 and 12.460 ± 1.25 μg/ml against L. infantum and L. amazonensis, respectively. The mechanism of action of these drugs was investigated by detecting changes in the phosphatidylserine (PS) exposure, the plasma membrane permeability, the mitochondrial membrane potential and the ATP level production in the treated parasites. By using the fluorescent probe SYTOX® Green, both triterpenic acids showed that they produce a time-dependent plasma membrane permeabilization in the treated Leishmania species. In addition, spectrofluorimeteric data revealed the surface exposure of PS in promastigotes. Both molecules reduced the mitochondrial membrane potential and decreased the ATP levels to 15% in parasites treated with IC90for 24 h. We conclude that the triterpenic acids tested in this study, show potential as future therapeutic alternative against leishmaniasis. Further studies are needed to confirm this.
Bibliographical noteFunding Information:
The authors are grateful to Æterna Zentaris Inc for providing Miltefosine. This work was supported by the grants RICET (project no. RD12/0018/0012 of the programme of Redes Temáticas de Investigación Cooperativa, FIS), Spanish Ministry of Health, Madrid, Spain and the Project FIS PI10/01298 “Protozoosis emergentes poramebas de vida libre: aislamiento y caracterización molecular, identificación de cepas transportadoras de otros agentes patógenos y búsqueda de quimioterapias efectivas” and PI13/00490 “Protozoosis Emergentes por Amebas de Vida Libre: Aislamiento, Caracterización, Nuevas Aproximaciones Terapéuticas y Traslación Clínica de los Resultados” from the Instituto de Salud Carlos III and by the FP7-REGPOT-2012-CT2012-316137-IMBRAIN project.IS was funded by an alternating Scholarship from the University of Carthage, Tunisian Ministry of Higher Education and Scientific Research and by CEI Canarias, Campus Atlántico Internacional. ALA was funded by a grant “ Ayudas del Programa de Formación de Personal Investigador, para la realización de Tesis Doctorales ” from the Agencia Canaria de Investigación, Innovación y Sociedad de la Información from the Canary Islands Government. CMMN was supported by a postdoctoral grant from the Fundación Canaria Manuel Morales, La Palma, Canary Islands. JCT thanks MAE-AECI for the fellowship. MRB was funded by CEI Canarias, Campus Atlántico Internacional and Becas Fundación Caja canarias para Postgraduados 2014. JLM was supported by the Ramón y Cajal Subprogramme from the Spanish Ministry of Economy and Competivity RYC-2011-08863.
© 2014 Elsevier B.V. All rights reserved.
- Bioassay fractionation
- Leishmania spp
- Mechanism of action
- Olive leaf extract