Towards effective natural anthraquinones to mediate antimicrobial photodynamic therapy of cutaneous leishmaniasis

Abstract

Cutaneous leishmaniasis (CL) is an important tropical neglected disease withbroad geographical dispersion. The lack of effective drugs has raised an urgent need to improveCL treatment, and antimicrobial photodynamic therapy (APDT) has been investigated as a newstrategy to face it with positive outcomes. Natural compounds have emerged as promisingphotosensitizers (PSs), but their use in vivo remains unexplored.Purpose: In this work, we investigated the potential of three natural anthraquinones (AQs) onCL induced by Leishmania amazonensis in BALB/c mice.Study Design/Methods: Animals were infected and randomly divided into four groups: CG(control, non-treated group), G5ClSor-gL (treated with 5-chlorosoranjidiol and green LED,520±10 nm), GSor-bL and GBisor-bL (treated with soranjidiol and bisoranjidiol, respectively,exposed to violet-blue LED, 410±10 nm). All AQs were assayed at 10 μM and LEDs delivereda radiant exposure of 45 J/cm2 with an irradiance of 50 mW/cm2. We assessed the parasiteburden in real time for three consecutive days. Lesion evolution and pain score were assessedover 3 weeks after a single APDT session.Results: G5ClSor-gL was able to sustain low levels of parasite burden over time. Besides,GSor-bL showed a smaller lesion area than the control group, inhibiting the disease progression.Conclusion: Taken together, our data demonstrate that monoAQs are promising compounds forpursuing the best protocol for treating CL and helping to face this serious health problem.Studies involving host-pathogen interaction as well as monoAQ-mediated PDT immuneresponse are also encouraged.