Efeito do extrato etanólico da própolis de Plebeia droryana (Hymenoptara: Apidae) na viabilidade de leucócitos humanos e em linhagens de melanoma e leucemia

Abstract

Cancer is a multifactorial disease influenced by lifestyle, genetic, and epigenetic factors that affect gene expression and lead to dysfunctional cellular processes, such as uncontrolled proliferation and apoptosis evasion. With approximately 10 million deaths per year, the demand for new therapies continues to grow. Brazil’s biodiversity, rich in bioactive natural products, emerges as a promising source, and alternatives such as apitherapy have been investigated in search of more effective treatments with fewer side effects. In this context, the present study aimed to investigate the effect of propolis from the stingless bee Plebeia droryana on healthy cells and cancer cell lines. Propolis samples were collected and the ethanolic extract of Plebeia droryana propolis (EEPPd) was prepared. The effects of EEPPd were then evaluated through a cell viability assay using the reagent 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) in peripheral blood mononuclear cells (PBMCs; healthy cells) and in cancer cell lines: murine melanoma (B16F10-Nex2), human melanoma (SK-MEL-103), and leukemia (Jurkat). PBMCs and cancer cells were treated with different concentrations (10–1000 µg/mL) of the extract for 24 h. The results show that EEPPd did not affect PBMC viability at concentrations below 250 µg/mL. The extract reduced the viability of all three cancer cell lines, although with distinct response patterns. In the murine melanoma line B16F10-Nex2, reduction occurred only at 500 and 1000 µg/mL (IC₅₀ = 783.3 µg/mL). In the human melanoma line SK MEL-103, the effect was observed from 25 to 1000 µg/mL (IC₅₀ = 614.1 µg/mL). The Jurkat leukemia lineage was the most sensitive, with significant reduction at 250, 500, and 1000 µg/mL (IC₅₀ = 447.59 µg/mL). Selectivity index (SI) analysis revealed values of 0.79 for B16F10-Nex2, 1.01 for SK-MEL-103, and 1.39 for Jurkat, indicating slight selectivity only for the latter. These findings suggest that concentrations below 250 µg/mL are safe and reinforce the potential of EEPPd as a candidate for future studies focused on elucidating mechanisms of action and assessing its anticancer activity.