Chemical characterization and leishmanicidal activity of Araucaria sp Brazilian brown propolis

Brazilian brown propolis from Araucaria sp is composed predominantly by a mixture of acid diterpenes and displays a wide spectrum of biological activities, including antiparasitary [1], [2]. Thus, the hydroalcoholic extract of Brazilian brown propolis (EBBP) was tested against promastigote forms of Leishmania amazonensis. The result revealed that EBBP is a rich source of potent leishmanicidal compounds since it displayed an IC₅₀ = 8.32 ± 0.61 µg · mL⁻¹ after 24 hours of incubation. Then, ten diterpenes were isolated from EBBP, identified and also biologically investigated but none of them showed promising leishmanicidal effect (IC₅₀ values higher than 50 µM). Due to these results, only EBBP was evaluated at its IC₅₀ concentration on intracellular amastigotes. After 48 hours of treatment EBBP reduced the internalization of parasites in about 58%. Morphological analysis of promastigotes by scanning electron microscopy treated with EBBP at 8.32 µg · mL⁻¹ (IC₅₀ concentration) revealed noticeable differences between the treated parasites and the control group, such as the losing of their fusiform morphology, and a significant damage in the cell membranes. In general, the results described herein pointed out EBBP as a promising natural source for further in vivo leishmanicidal investigation and bring news perspectives about synergistic studies between the main isolated diterpenes.

Publication History

Article published online:
12 December 2022

• References

• 1 Paula LAL, Cândido ACBB, Santos MFC. et al. Antiparasitic properties of propolis extracts and their compounds. Chem Biodiver 2021; 18: e2100310
• 2 Santos MFC, Oliveira LC, Ribeio VP. et al. Isolation of diterpenes from Araucaria sp Brazilian brown propolis and development of a validated HPLC method for its analysis. J Sep Sci 2021; 44: 3089-3097