RESUMO

Uncaria tomentosa is a plant native to the Amazon that has immunomodulatory and antitumor properties due to the alkaloids found in the plant, being able to modify the immune response by potentiating or suspending the action of cytokines secreted by macrophages that induce the immune response, either by the classical route (M1) or through the alternative route (M2). Macrophages activated by M1 convert L-arginine into L-citrulline and nitric oxide (NO), whereas macrophages activated by the M2 pathway use the enzymatic activity of arginase to convert the same substrate into L-ornithine and urea. The aim of this work was to evaluate the immunostimulating activity of the crude hydroalcoholic extract from the bark of the U. tomentosa stem in RAW 264.7 macrophages. Concentrations of 0.2, 0.1 and 0.05 mg/mL of U. tomentosa extract associated with LPS, INF-γ and IL-4 inducers were tested by determining NO production and arginase enzyme activity. Nitric oxide production was enhanced by the extract when associated with LPS and LPS + INF-γ inducers. In the activity of the arginase enzyme, the extract decreased the stimulation of IL-4 on the enzyme, mainly at 0.2 mg/mL concentration. Therefore, it is concluded that the crude hydroalcoholic extract of the stem bark of U. tomentosa in RAW 264.7 cells, at a concentration of 0.2 mg/mL, showed considerable pro-inflammatory activity.

Assuntos

Unha-de-Gato , Arginase , Interleucina-4 , Lipopolissacarídeos/farmacologia , Óxido Nítrico , Macrófagos , Extratos Vegetais/farmacologia

RESUMO

Abstract Uncaria tomentosa is a plant native to the Amazon that has immunomodulatory and antitumor properties due to the alkaloids found in the plant, being able to modify the immune response by potentiating or suspending the action of cytokines secreted by macrophages that induce the immune response, either by the classical route (M1) or through the alternative route (M2). Macrophages activated by M1 convert L-arginine into L-citrulline and nitric oxide (NO), whereas macrophages activated by the M2 pathway use the enzymatic activity of arginase to convert the same substrate into L-ornithine and urea. The aim of this work was to evaluate the immunostimulating activity of the crude hydroalcoholic extract from the bark of the U. tomentosa stem in RAW 264.7 macrophages. Concentrations of 0.2, 0.1 and 0.05 mg/mL of U. tomentosa extract associated with LPS, INF-γ and IL-4 inducers were tested by determining NO production and arginase enzyme activity. Nitric oxide production was enhanced by the extract when associated with LPS and LPS + INF-γ inducers. In the activity of the arginase enzyme, the extract decreased the stimulation of IL-4 on the enzyme, mainly at 0.2 mg/mL concentration. Therefore, it is concluded that the crude hydroalcoholic extract of the stem bark of U. tomentosa in RAW 264.7 cells, at a concentration of 0.2 mg/mL, showed considerable pro-inflammatory activity.

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Resumo A Uncaria tomentosa é uma planta nativa da Amazônia que possui propriedades imunomoduladoras e antitumorais devido aos alcaloides encontrados no vegetal, sendo capaz de modificar a resposta imune ao potencializar ou suspender a ação de citocinas secretadas por macrófagos que induzem a resposta imune, seja pela via clássica (M1) ou pela via alternativa (M2). Macrófagos ativados pela M1 converte L-arginina em L-citrulina e óxido nítrico (NO), já os macrófagos ativados pela via M2 utilizam a atividade enzimática da arginase para converter o mesmo substrato em L-ornitina e ureia. O trabalho teve como objetivo avaliar a atividade imunoestimuladora do extrato hidroalcoólico bruto da casca do caule da U. tomentosa em macrófagos RAW 264.7. Foram testadas as concentrações 0.2, 0.1 e 0.05 mg/mL do extrato de U. tomentosa associadas aos indutores LPS, INF-γ e IL-4, por meio da determinação da produção de NO e atividade da enzima arginase. A produção de óxido nítrico foi potencializada pelo extrato quando associado aos indutores LPS e LPS + INF-γ. Na atividade da enzima arginase, o extrato diminuiu a estimulação da IL-4 sobre a enzima, principalmente na concentração 0.2 mg/mL. Portanto, conclui-se que o extrato hidroalcoólico bruto da casca do caule de U. tomentosa em células RAW 264.7, na concentração 0.2 mg/mL, demostrou atividade pró-inflamatória considerável.