Immunosuppressant activity and morphological changes in Leishmania amazonensis treated with extracts from seeds of Lonchocarpus cultratus

Banhuk, Fernanda Weyand; Staffen, Izabela Virg&iacute;nia; Tomiotto-Pellissier, Fernanda; Bortoleti, Bruna Taciane Da Silva; Pavanelli, Wander Rog&eacute;rio; Ayala, Thaís Soprani; Menolli, Rafael Andrade

doi:10.22038/ajp.2025.26025

Immunosuppressant activity and morphological changes in Leishmania amazonensis treated with extracts from seeds of Lonchocarpus cultratus

Articles in Press

Document Type : Original Research Article

Authors

¹ Laboratory of Applied Immunology, Center of Medical and Pharmaceutical Sciences, State University of West Paraná, Cascavel, Paraná, Brazil

² Biosciences and Biotechnology Postgraduate Program, Carlos Chagas Institute, Curitiba, Paraná, Brazil

³ Biosciences and Biotechnology Postgraduate Program, Carlos Chagas Institute, (ICC/Fiocruz/PR)

10.22038/ajp.2025.26025

Abstract

Objective: The first-line drugs used for treating leishmaniasis are highly costly and aggressive. Extracts from Lonchocarpus cultratus have trypanocidal activity and possess several compounds with biological activities. This study sought to observe the in vitro anti-Leishmania amazonensis action of extracts from seeds of L. cultratus. Furthermore, the immunomodulatory and antioxidant characteristics of the extracts were determined.
Materials and Methods: Sequential extraction with hexane, dichloromethane, and methanol was performed to obtain extracts from L. cultratus seeds, which were characterized via ¹H NMR. Promastigotes, intracellular amastigotes, and murine macrophages were treated with increasing concentrations of the extracts, and the inhibition rates were determined by scanning electron microscopy (SEM) analysis of the extracellular forms of the extracts. The immunomodulatory activity of the extract was determined against stimulated RAW macrophages.
Results: Isocordoin and lonchocarpine were identified in dichloromethane and hexane extracts. Dichloromethane (LDS), hexane (LHS), and methanolic (LMS) extracts inhibited promastigote cell growth (IC₅₀ values of 5.18±1.18, 5.25±1.47, and 33.89±1.62 μg/ml, respectively) and decreased the number of amastigotes in the macrophages (IC₅₀ values of 1.41±0.31, 6.33±1.42, and 5.87±1.37 μg/ml, respectively). Hexane and methanolic extracts showed low toxicity in macrophages, resulting in a high selectivity index against promastigotes and amastigotes. In addition, the three extracts immunomodulated macrophages, reducing nitric oxide (NO) secretion.
Conclusion: The results revealed that the activities of the L. cultratus extracts included leishmanicidal effects, low cytotoxicity to macrophages, and immunosuppression in vitro.

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