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Investigation of antimalarial activity, cytotoxicity and action mechanism of piperazine derivatives of betulinic acid
Author(s) -
Silva Gloria N. S.,
Schuck Desirée C.,
Cruz Laura N.,
Moraes Miriam S.,
Nakabashi Myna,
Gosmann Grace,
Garcia Célia R. S.,
Gnoatto Simone C. B.
Publication year - 2015
Publication title -
tropical medicine and international health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.056
H-Index - 114
eISSN - 1365-3156
pISSN - 1360-2276
DOI - 10.1111/tmi.12395
Subject(s) - betulinic acid , piperazine , cytotoxicity , chemistry , traditional medicine , mechanism of action , antimalarial agent , pharmacology , malaria , biology , plasmodium falciparum , biochemistry , organic chemistry , in vitro , medicine , immunology , genetics
Objectives To semisynthesise piperazine derivatives of betulinic acid to evaluate antimalarial activity, cytotoxicity and action mechanism. Methods The new derivatives were evaluated against the CQ ‐sensitive Plasmodium falciparum 3D7 strain by flow cytometry ( FC ) using YOYO ‐1 as stain. Cytotoxicity of 4a and 4b was performed with HEK 293T cells for 24 and 48 h by MTT assay. The capability of compound 4a to modulate Ca 2+ in the trophozoite stage was investigated. The trophozoites were stained with Fluo4‐ AM and analysed by spectrofluorimetry. Effect on mitochondrial membrane potential (ΔΨ m ) was tested for 4a by FC with Di OC 6 (3) as stain. For β ‐haematin assay, 4a was incubated for 24 h with reagents such as haemin, and the fluorescence was measured by FlexStation at an absorbance of 405 nm. Results Antimalarial activity of 4a and 4b was IC 50 = 1 and 4 μ m , respectively. Compound 4a displayed cytotoxicity with IC 50 = 69 and 29 μ m for 24 and 48 h, respectively, and 4b was not cytotoxic at the tested concentrations. Addition of 4a leads to an increase in cytosolic Ca 2+ . We have measured ΔΨm after treating parasites with the compound. Data on Figure 4a show that mitochondria were not affected. The action mechanism for 4a, inhibition of β ‐haematin formation (17%), was lower than CQ treatment (83%; IC 50 = 3 m m ). Conclusion Compound 4a showed excellent antimalarial activity, and its action mechanism is involved in Ca 2+ pathway(s).