Novel Gallate Triphenylphosphonium Derivatives with Potent Antichagasic Activity

PLoS One. 2015 Aug 28;10(8):e0136852. doi: 10.1371/journal.pone.0136852. eCollection 2015.

Abstract

disease is one of the most neglected tropical diseases in the world, affecting nearly 15 million people, primarily in Latin America. Only two drugs are used for the treatment of this disease, nifurtimox and benznidazole. These drugs have limited efficacy and frequently induce adverse effects, limiting their usefulness. Consequently, new drugs must be found. In this study, we demonstrated the in vitro trypanocidal effects of a series of four gallic acid derivatives characterized by a gallate group linked to a triphenylphosphonium (TPP(+)) moiety (a delocalized cation) via a hydrocarbon chain of 8, 10, 11, or 12 atoms (TPP(+)-C8, TPP(+)-C10, TPP(+)-C11, and TPP(+)-C12, respectively). We analyzed parasite viability in isolated parasites (by MTT reduction and flow cytometry) and infected mammalian cells using T. cruzi Y strain trypomastigotes. Among the four derivatives, TPP(+)-C10 and TPP(+)-C12 were the most potent in both models, with EC50 values (in isolated parasites) of 1.0 ± 0.6 and 1.0 ± 0.7 μM, respectively, and were significantly more potent than nifurtimox (EC50 = 4.1 ± 0.6 μM). At 1 μM, TPP(+)-C10 and TPP(+)-C12 induced markers of cell death, such as phosphatidylserine exposure and propidium iodide permeabilization. In addition, at 1 μM, TPP(+)-C10 and TPP(+)-C12 significantly decreased the number of intracellular amastigotes (TPP(+)-C10: 24.3%, TPP(+)-C12: 19.0% of control measurements, as measured by DAPI staining) and the parasite's DNA load (C10: 10%, C12: 13% of control measurements, as measured by qPCR). Based on the previous mode of action described for these compounds in cancer cells, we explored their mitochondrial effects in isolated trypomastigotes. TPP(+)-C10 and TPP(+)-C12 were the most potent compounds, significantly altering mitochondrial membrane potential at 1 μM (measured by JC-1 fluorescence) and inducing mitochondrial transition pore opening at 5 μM. Taken together, these results indicate that the TPP(+)-C10 and TPP(+)-C12 derivatives of gallic acid are promising trypanocidal agents with mitochondrial activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Chagas Disease / drug therapy
  • Chagas Disease / parasitology
  • Chlorocebus aethiops
  • Gallic Acid / pharmacology*
  • Humans
  • Macrophages / drug effects
  • Macrophages / metabolism
  • Macrophages / parasitology*
  • Membrane Potential, Mitochondrial / drug effects
  • Mice
  • Mitochondria / drug effects
  • Parasitic Sensitivity Tests / methods
  • Trypanocidal Agents / pharmacology*
  • Trypanosoma cruzi / drug effects*
  • Trypanosoma cruzi / isolation & purification*
  • Trypanosoma cruzi / metabolism
  • Vero Cells

Substances

  • Trypanocidal Agents
  • Gallic Acid

Grants and funding

This work was supported by the following grants from the Consejo Nacional de Ciencia y Tecnología (CONICYT-Chile: http://www.conicyt.cl): FONDECYT 11110182 (RLM), FONDECYT 1130772 (JF), FONDECYT 1130189 (JDM), and the Academy Insertion Grant 791220004 (JAJ). The following grants were obtained from the Vicerrectoría de Investigación y Desarrollo, Universidad de Chile (http://www.uchile.cl/investigacion): U-INICIA 11/07 (RLM) and U-INICIA 2014 (JAJ). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.