Evaluation of the antioxidant potential of Copaifera multijuga in Ehrlich tumor-bearing mice

Copaifera multijuga, commonly known as copaiba, is popularly used in the form of tea for various conditions due to the presence of antioxidant substances in its composition, which protect cells against damage caused by free radicals. Its oleoresin is also used as an anti-inflammatory and antitumoral agent. The present study investigated the antioxidant effect of the ethanolic extract of copaiba stem bark on Swiss mice inoculated with solid Ehrlich tumors. Mice were inoculated subcutaneously with 1x106 Ehrlich's tumor cells and treated via gavage with ethanolic extract of copaiba for thirty days, with doses varying between 100 and 200 mg kg-1. Biochemical analyses of enzymatic antioxidants [superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST)], non-enzymatic antioxidants [reduced glutathione (GSH) and ascorbic acid (ASA)], substances reactive to thiobarbituric acid (TBARS) and protein carbonylation (carbonyl) in different tissues were significantly affected. The extract administered at 200 mg kg-1 presented higher antioxidant capacity in the liver, increased CAT, GST, GSH and decreased TBARS, as well as increased CAT activity and protein carbonylation in brain tissue. The results showed that the copaiba extract was able to reverse the oxidative stress caused by solid Ehrlich tumor, probably due to the presence of antioxidant compounds, and had potential antineoplasic effect after a 30-day treatment. (AU)

Natural killer activity of the spleen cells of Ehrlich tumor-bearing mice treated with Copaifera multijuga extract / Atividade natural killer das células esplênicas de camundongos portadores do tumor de Ehrlich tratados com extrato de Copaifera multijuga

AIMS: Copaifera multijuga Hayne oleoresin is commonly used in traditional medicine owing to its anti-inflammatory, antiseptic, antitumor, and antibacterial properties. However, little is known about the effect of the compounds from the bark of this plant. In this study, the immunomodulatory effect of the ethanolic extract of C. multijuga bark via natural killer activity of non-adherent spleen cells of Ehrlich tumor-bearing mice was evaluated. METHODS: Male Swiss mice were inoculated subcutaneously with 1×106 Ehrlich tumor cells (Ehrlich and Ehrlich/C. multijuga group) or phosphate buffered saline solution (control group and C. multijuga group) and treated orally daily with C. multijuga extract (200 mg kg-1, 0.1 mL per mouse, for the Ehrlich/C. multijuga and C. multijuga groups) or phosphate buffered saline solution (control group and Ehrlich group). The four experimental groups consisted in eight mice each and were organized in two sets, one treated for seven days and another treated for 14 days, totalizing 64 mice throughout the experiment. Twenty-four hours after the last oral administration, the mice were euthanized and the spleen tissue was isolated to prepare a non-adherent spleen cell suspension and to evaluate natural killer activity. Data are presented as the cell lysis percentage of Yac.1 target cells by non-adherent spleen cells. RESULTS: Treatment for seven days increased natural killer activity in the Ehrlich/C. multijuga group (21.20±8.89, p<0.05) compared to the control group (3.14±2.71, p<0.05); however, this effect was not maintained in the groups treated for 14 days (Control: 6.02±6.98, Ehrlich: 4.82±7.72, C. multijuga: 2.07±2.10, Ehrlich/C. multijuga: 2.01±1.63, p>0.05). CONCLUSIONS: Treatment for seven days with an ethanolic extract of C. multijuga bark enhanced the natural killer activity of non-adherent spleen cells from Ehrlich tumor-bearing mice.

OBJETIVOS: O óleo-resina de Copaifera multijuga Hayne é popularmente utilizado na medicina tradicional por suas propriedades antiinflamatória, antisséptica, antitumoral e antibacteriana. Entretanto, há poucos estudos sobre o efeito dos compostos obtidos da casca da planta. Assim, o objetivo deste trabalho foi avaliar o efeito imunomodulador do extrato etanólico da casca da C. multijuga na atividade natural killer das células esplênicas não aderentes de animais portadores do tumor de Ehrlich. MÉTODOS: Camundongos Swiss machos foram inoculados subcutaneamente com 1×106 células do tumor de Ehrlich (grupo Ehrlich e Ehrlich/C. multijuga) ou com solução salina tamponada (grupo controle e C. multijuga) e tratados diariamente (gavagem) com extrato de C. multijuga (200 mg kg-1, 0,1mL cada um, para os grupos Ehrlich/C. multijuga e C. multijuga) ou com solução salina tamponada (grupo controle e grupo Ehrlich). Os quatro grupos experimentais consistiram de oito animais cada e foram organizados em dois conjuntos, um tratado por sete dias e outro tratado por 14 dias, totalizando 64 animais durante todo o experimento. Após 24 horas do término do tratamento, os animais foram eutanasiados para obtenção da suspensão de células esplênicas não aderentes e avaliação da atividade natural killer. Os resultados são apresentados como porcentagem da lise celular das células alvo Yac.1 pelas células esplênicas não aderentes. RESULTADOS: A análise dos resultados demonstrou que aos sete dias de tratamento a C. multijuga aumentou a atividade natural killer no grupo Ehrlich/C. multijuga (21,20±8,89, p<0,05) em comparação ao grupo controle (3,14±2,71, p<0,05), entretanto tal efeito não foi mantido nos grupos tratados por 14 dias (Controle: 6,02±6,98; EHR: 4,82±7,72; C. multijuga: 2,07±2,10; EHR/C. multijuga: 2,01±1,63, p>0,05). CONCLUSÕES: Os resultados demonstraram que o tratamento com o extrato etanólico da casca de C. multijuga favoreceu a atividade natural killer das células esplênicas não aderentes dos animais portadores do tumor de Ehrlich apenas aos sete dias de tratamento.