Nitro-Heterocyclic compounds induce apoptosis-like effects in Leishmania (L). amazonensis promastigotes

 

Daiane Barros Dias Mendonça^1  2, Renata Ellen Costa Silva^1  2, Fanny Palace-Berl³, Cleusa F. H. Takakura⁴, Sandra Regina C Soares⁵, Lucia Maria Almeida Braz^1  2, Leoberto Costa Tavares³, Jose Angelo Lauletta Lindoso^{1  2  6  7}

 

1 Laboratory of Serum Epidemiology, Faculty of Medicine, University of São Paulo, São Paulo, SP, Brazil

2 Institute of Tropical Medicine, University of São Paulo, São Paulo, SP, Brazil

3 Laboratory of Planning and Development of Pharmaceuticals, Department of Biochemical-Pharmaceutical Technology, Faculty of Pharmacy, University of São Paulo, São Paulo, SP, Brazil

4 Department of Pathology, Faculty of Medicine, University of São Paulo, São Paulo, SP, Brazil

5 Laboratory of Protozoology, Institute of Tropical Medicine, Faculty of Medicine, University of São Paulo, São Paulo, SP, Brazil

6 Institute of Infectology Emilio Ribas, Secretary of State for Health, São Paulo, SP, Brazil

7 Center for Tropical Medicine, Faculty of Medicine, University of Brasilia, Brasilia, Federal District, Brazil.

 

ABSTRACT

Background:

Three drugs - pentavalent antimonials, amphotericin B and pentamidine - are currently used for leishmaniasis treatment. They are administered for long periods, only parenterally, and have high cardiac, renal and hepatic toxicities. Therefore, the investigation of new compounds is required. Nitro-heterocyclic derivatives have been used as possible drug candidates to treat diseases caused by trypanosomatids.

 

Methods:

Leishmania (L.) amazonensis promastigotes (MHO/BR/73/M2269), maintained in the Laboratório de Soroepidemiologia - Instituto de Medicina Tropical- USP, were exposed to five nitroheterocyclic derivatives, with differences at phenyl-ring position 4: BSF-C4H9' BSF-H, BSF-NO2' BSF-CH3 and BSF-Cl, for 48 hours. After analyzing viability (MTT assay), we evaluated cellular-morphology activity of compounds by transmission electron microscopy (TEM) and measurement of apoptosis (phosphatidylserine expression) by flow cytometry.

 

Results:

EC50 of amphotericin B and BSF-CH3 were 0.50 (M and 0.39 (M respective. Other nitro-heterocyclic compounds presented EC50 higher than amphotericin B. All compounds showed greater AV- and PI-positive expression than amphotericin B at 100 (M, except BSF-NO2. TEM showed complete nuclear disfigurement with 100 (M of BSF-NO2' 25 and 6.25 (M of BSF-H, and 6.25 (M BSF-Cl; presence of vesicles within the flagellar pocket with 25 (M BSF-H; alteration of the kinetoplast with 25 (M BSF-C4H9' 25 (M of BSF-H, 6.25 (M BSF-CH3 and 6.25 (M of BSF-Cl.

 

Conclusions:

Nitro-heterocyclic compounds have shown activity against promastigotes of L. amazonensis, at lower concentrations. However, improvement of compound scaffolds are needed to assist the elucidation of the mechanism of action and to achieve greater activity.

 

Keywords: Leishmaniasis treatment; Nitro-heterocyclic compounds; Leishmania (L.) amazonensis

 

Received: May 03, 2018.

Accepted: November 30, 2018.

 

Correspondence: jlindoso@usp.br

 

Competing interests The authors declare that there are no conflicts of interest.

 

Authors' contributions DBDM designed and performed all experiments and wrote the manuscript. RECS take part in the experiments related to cytometry. FPB was responsible for synthesis of compounds and corrected the manuscript. CFHT took part in the experiments related to transmission electron microscopy. SRCS helped in all experiments. LMAB helped to write the manuscript. LCT was responsible for compounds and corrected the manuscript. JALL designed the experiments, and wrote and corrected the manuscript.