Análise da influência do extrato EPs®7630 de Pelargonium sidoides na atividade tumoricida de linfócitos citotóxicos contra células Jurkat

Abstract

The immune response, especially that related to CD8 T lymphocytes and NK cells, is essential to combat tumor cells. Recent studies highlight the role of phytotherapeutics in the complementary treatment of neoplasms, with Pelargonium sidoides (P. sidoides) extract being a promising example, with immunomodulatory properties. Studies on the cytotoxic and antineoplastic potential of lymphocytes treated with P. sidoides are scarce in the literature. In this sense, the present study sought to analyze the effect of P. sidoides (EPs® 7630 extract) on the capacity of cytotoxic lymphocytes to eliminate tumor cells of hematologic origin in vitro, as well as to perform phytochemical screening of the extract and determine the IC50 in Jurkat tumor cell line and PBMCs. Qualitative analysis of metabolites was performed on a commercial ethanolic extract of the roots of P. sidoides (EPs® 7630) Kaloba®. To determine the IC50, treatment for 24 hours at concentrations of 40, 400, 4,000, 40,000 and 400,000 μg/mL was evaluated. Cell death was quantified by flow cytometry with 7-amino-actinomycin D (7-AAD) labeling. Peripheral blood mononuclear cells (PBMCs) from healthy individuals and the Jurkat tumor cell line were cultured and exposed to different times and concentrations of the EPs® 7630 extract to evaluate cytotoxicity. Death was also quantified by 7-AAD labeling, identified by flow cytometry. The results of the study showed that the EPs® 7630 extract, obtained from the roots of Pelargonium sidoides, contains a variety of secondary metabolites such as coumarins, phenols, flavonoids, flavones and flavanones. PBMCs presented an IC50 of 60,470 μg/mL and the Jurkat tumor cell line, 63,700 μg/mL of the extract. In the experiment in which PBMCs were treated for 24 hours with EPs® 7630, there was a higher percentage of Jurkat cell death by cells treated with 100 μg/mL, compared to untreated cells and those treated with 10 μg/mL. Treatment at concentrations of 50 μg/mL and 100 μg/mL promoted greater tumor cell death compared to the untreated group in the assay for 4 hours in concomitant treatment. Regarding the co-culture for 6 hours, it was observed that there was a higher percentage of death of Jurkat cells in those treated with EPs® 7630 in both the 10:1 and 30:1 ratio. The results presented here regarding the enhancement of the antitumor capacity of PBMCs by the EPs® 7630 extract of P. sidoides provide new insights into the potential of using this drug as a complementary therapy for neoplasms.