E-Cyanoacrylamides and 5-Imino Pyrrolones against Trypanosoma cruzi: Activity and Induced Mechanisms of Cell Death

Abstract

Chagas disease is caused by a protozoan parasite called Trypanosoma cruzi. The infection produces a first clinical phase, commonly asymptomatic or showing non-specific symptoms, and a second chronic phase characterized by cardiac and digestive dysfunctions in some individuals with the disease. This disease affects 7 million people and has been categorized by the World Health Organisation as a neglected tropical disease. In addition, the drugs used to combat it were developed in the 1970s and present major toxicity problems and limited efficacy in the chronicity of the disease. This has led to research into new active compounds that are effective against the disease, with studies on cyanoderivatives showing promising activity. In this work, eight active E-cyanoacrylamides/5-imino pyrrolones were studied. Compounds B and F showed excellent activity, while compounds C and G stood out for their lower cytotoxicity. After correlating the activity and cytotoxicity of the compounds, it was observed that compounds B, C, and G obtained the most favourable results. Various cell death studies were carried out with these compounds, and it was determined that all of them produced programmed cell death, with compound B standing out as being at a late stage in the process.

Keywords: ADME; Chagas; Trypanosoma cruzi; chemoterapy; cyanoacrilamides; iminopirrolones; programmed cell death.

Figure 1

Molecular structure of benznidazole used as reference treatment.

Figure 2

Results of ATP levels presented as a percentage relative to the negative control (C-, without any treatment). A Tukey test with GraphPad.PRISM^® 10.1.1 software was conducted to test the statistical differences between means (p < 0.0001 [****]). Benznidazole was added as the reference treatment and sodium azide was used as the positive control.

Figure 3

Results of plasmatic membrane permeability levels presented as a percentage of fluorescent cells, and the statistical analysis was conducted relative to the negative control (C-, without treatment). A Tukey test with GraphPad.PRISM^® 10.1.1 software was conducted to test the statistical differences between means (p < 0.05 [*]; p < 0.001 [***]; p < 0.0001 [****]). Benznidazole was added as the reference treatment and triton was used as the positive control.

Figure 4

Results of mitochondrial membrane potential alterations, expressed as a percentage relative to the negative control (C-, without any treatment). A Tukey test with GraphPad.PRISM^® 10.1.1 software was conducted to test the statistical differences between means. (p < 0.0001 [****]). Benznidazole was added as the reference treatment and carbonyl cyanide m-chlorophenyl hydrazone (CCCP) was used as the positive control.

Figure 5

Results of double stain Hoechst/PI, expressed as a percentage relative to the negative control (C-, without any treatment). A Tukey test with GraphPad.PRISM^® 10.1.1 software was conducted to test the statistical differences between means. (p > 0.05, non-significative [^ns]; p < 0.01 [**]; p < 0.0001 [****]). Benznidazole was added as the reference treatment.

Figure 6

Results of the accumulation of reactive oxygen species (ROS), expressed as a percentage relative to the negative control (C-, without any treatment). A Tukey test with GraphPad.PRISM^® 10.1.1 software was conducted to test the statistical differences between means. (p < 0.01 [**]; p < 0.0001 [****]). Benznidazole was added as the reference treatment and oxygen peroxide as the positive control.

Figure 7

Boiled-egg graph representing the SwissADME predictions. The yellow area refers to the probability to pass the blood–brain barrier and the white area represents the high probability of absorption in the gastrointestinal tract. Each compound is presented as a point; those that were not shown to be P-gp substrates (PGP-) are indicated in red.