| dc.description | Background: Cutaneous leishmaniasis (CL) is a vector-borne disease caused by obligate protist parasites from the
genus Leishmania. The potential toxicity as well as the increased resistance of standard treatments has encouraged
the development of new therapeutical strategies. Photodynamic inactivation (PDI) combines the use of
a photosensitizer and light to generate reactive oxygen species and kill cells, including microorganisms. Vegetal
kingdom constitutes an important source of bioactive compounds that deserve to be investigated in the search of
naturally occurring drugs with leishmanicidal activity.
Purpose: The purpose of this study was to test the antiparasitic activity of PDI (ApPDI) of five natural anthraquinones
(AQs) obtained from Heterophyllaea lycioides (Rusby) Sandwith (Rubiacae). To support our results,
effect of AQ mediated-PDI on parasite??s morphology and AQ uptake were studied. Cytotoxicity on fibroblasts
was also evaluated.
Study design/Methods: Two monomers, soranjidiol (Sor) and 5-chlorosoranjidiol (5-ClSor) plus three bi-anthraquinones
(bi-AQs), bisoranjidiol (Bisor), 7-chlorobisoranjidiol (7-ClBisor) and Lycionine (Lyc) were selected for
this study. Recombinant L. amazonensis promastigote strain expressing luciferase was subjected to AQs and LED
treatment. Following irradiation with variable light parameters, cell viability was quantified by bioluminescence.
Alteration on parasite's morphology was analyzed by scanning electron microscopy (SEM). In addition, we
verified the AQ uptake in Leishmania cells by fluorescence and their toxicity on fibroblasts by using MTT assay.
Results: Bisor, Sor and 5-ClSor exhibited photodynamic effect on L. amazonensis. SEM showed that promastigotes
treated with Bisor-mediated PDI exhibited a significant alteration in shape and size. Sor and 5-ClSor presented
higher uptake levels than bi-AQs (Bisor, Lyc and 7-ClBisor). Finally, Sor and Bisor presented the lowest toxic
activity against fibroblasts.
Conclusion: Taking together, our results indicate that Sor presents the highest specificity towards Leishmania
cells with no toxicity on fibroblasts. | |
