Dados do Trabalho

Título

Bioactive content and anti-Leishmania amazonensis activity of geopropolis extracts

Introdução

Leishmania amazonensis the etiological agent of human tegumentary leishmaniasis in Brazil. Current treatment relies on the use of pentavalent antimonials and amphotericin B, despite their high toxicity and variable efficacy. Geopropolis, a resinous material produced by stingless bees, is rich in phenolics and has been attracting attention for its pharmacological properties.

Objetivo (s)

The present study aimed to evaluate the anti-L. amazonensis activity of geopropolis produced by the stingless bees Tetragona clavipes, Tetragonisca angustula, and Scaptotrigona postica.

Material e Métodos

The geopropolis were subjected to maceration in 95% ethanol for 12 h, followed by filtration and solvent evaporation, resulting in the extracts TCGE (T. clavipes), TAGE (T. angustula), and SPGE (S. postica). The total flavonoid (TFC) content was determined spectrophotometrically by the flavonoid-aluminum complex formation method. Cytotoxicity was assessed against RAW 264.7 and VERO cell lines after 48 h treatment with the extracts (30-1000 µg.mL-1) using the MTT method. Hemolytic activity (ethical approval CEPUFRJ 68341721.0.0000.5257) was determined spectrophotometrically by measuring hemoglobin release after erythrocytes were exposed to extracts (15-1000 µg.mL-1) for 1 h. The viabilities of L. amazonensis promastigotes and axenic amastigotes were assessed using the drug microdilution method (6-400 µg.mL-1), followed by resazurin colorimetric assay. 

Resultados e Conclusão

Among the extracts, TAGE showed the highest TFC (471 mg QE/g) values. SPGE and TAGE showed lower cytotoxicity to VERO and RAW 264.7 cell lines, with CC50 values of 100 and 143 µg.mL-1, respectively. In addition, SPGE stood out for its lower hemolytic activity (HC50 = 609 µg.mL-1). All extracts demonstrated anti-L. amazonensis activity, with TCGE displaying the best results (IC50 = 22.7 and 19 µg.mL-1 against promastigotes and amastigotes, respectively). Despite containing low amounts of phenolics, TCGE showed the best results against both parasite evolutive forms. These results suggest that other chemical classes might be responsible for the antileishmanial activity. This study paves the way for further investigation into anti-L. amazonensis agents in stingless bee geopropolis.

Palavras Chave

Leishmania amazonensis; tegumentary leishmaniasis; Brazilian stingless bee