Antiparasitic evaluation of betulinic acid derivatives reveals effective and selective anti-Trypanosoma cruzi inhibitors

• Published in: Experimental parasitology Vol. 166; pp. 108 - 115
• Main Authors: Meira, Cássio Santana, Barbosa-Filho, José Maria, Lanfredi-Rangel, Adriana, Guimarães, Elisalva Teixeira, Moreira, Diogo Rodrigo Magalhães, Soares, Milena Botelho Pereira
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-07-2016
• Subjects: Animals; Annexin A5; Betulinic acid; Chagas disease; Coloring Agents; Drug Synergism; Flow Cytometry; Inhibitory Concentration 50; Macrophages, Peritoneal - drug effects; Macrophages, Peritoneal - parasitology; Mice; Mice, Inbred BALB C; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Natural compounds; Nitroimidazoles - pharmacology; Propidium; Semi-synthetic; Staining and Labeling; Triterpenes - chemistry; Triterpenes - isolation & purification; Triterpenes - pharmacology; Triterpenoids; Trypanocidal Agents - chemistry; Trypanocidal Agents - isolation & purification; Trypanocidal Agents - pharmacology; Trypanosoma cruzi; Trypanosoma cruzi - drug effects; Trypanosoma cruzi - ultrastructure; Ziziphus - chemistry; Chagas disease; Natural compounds; Triterpenoids; Semi-synthetic; Betulinic acid; Trypanosoma cruzi
• ISSN: 0014-4894; 1090-2449
• DOI: 10.1016/j.exppara.2016.04.007

Betulinic acid is a pentacyclic triterpenoid with several biological properties already described, including antiparasitic activity. Here, the anti-Trypanosoma cruzi activity of betulinic acid and its semi-synthetic amide derivatives (BA1-BA8) was investigated. The anti-Trypanosoma cruzi activity and selectivity were enhanced in semi-synthetic derivatives, specially on derivatives BA5, BA6 and BA8. To understand the mechanism of action underlying betulinic acid anti-T. cruzi activity, we investigated ultrastructural changes by electron microscopy. Ultrastructural studies showed that trypomastigotes incubated with BA5 had membrane blebling, flagella retraction, atypical cytoplasmic vacuoles and Golgi cisternae dilatation. Flow cytometry analysis showed that parasite death is mainly caused by necrosis. Treatment with derivatives BA5, BA6 or BA8 reduced the invasion process, as well as intracellular parasite development in host cells, with a potency and selectivity similar to that observed in benznidazole-treated cells. More importantly, the combination of BA5 and benznidazole revealed synergistic effects on trypomastigote and amastigote forms of T. cruzi. In conclusion, we demonstrated that BA5 compound is an effective and selective anti-T. cruzi agent.
[Display omitted]
•Terpenoids are potent and selective trypanocidal agents.•BA5 destroys parasite cells by necrotic death.•Betulinic acid derivatives inhibit the growth of intracellular amastigotes of T. cruzi.•Combination of BA5 and benznidazole showed synergistic effects.