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.

Euphorbia tirucalli L. is commonly used to treat various pathologies, including cancer. The objective of this study was to evaluate the effect of a crude extract of E. tirucalli on the development of Ehrlich solid tumors and immune function. We prepared an extract by macerating the aerial parts of the plant with 80% ethanol (1:10 g/v) for 15 days. Its effects on tumor development were assessed in male Swiss mice (n=10). The mice were injected subcutaneously with 10⁶ tumor cells and then treated by gavage daily with the extract (33.33, 67, and 133.34 mg kg-1) or saline (0.5% ethanol) for 30 days. The treatment had no toxic effect and did not reduce tumor growth. However, the weight of tumor mass was lowest in the mice treated with extract at 67 mg kg-1. Immunomodulatory activity was evaluated in mice (n=8), with and without tumors, treated with the extract (67 mg kg-1), under the same conditions as described above for 7 and 14 days. Lymphoproliferation, NK activity and IL-12, TNF-a, IFN-y, and IL-10 levels did not differ significantly between the groups. However, IL-4 levels were reduced in the E. tirucalli treated groups at 7 and 14 days when compared to the controls. We concluded that the extract is not toxic and cannot inhibit Ehrlich solid tumor development. Its immunomodulatory activity involves its ability to modulate IL-4 levels.