Effects of Dexamethasone (A, B), L-NAME (C, D), aqueous (E, F) and methanol (G, H) extracts of Paullinia pinnata on cell viability and nitric oxide production by non-stimulated macrophages. None of the treatments significantly affected the NO production although extracts at 30 and 100 μg/ml (E, G) tend to reduce it. The methanol extract at 100 μg/ml significantly reduced the cell viability. Each bar represents the mean ± SEM of five repetitions. *p<0.05 significant difference compared to control (0 μg/ml) using 1-Way ANOVA with Tukey as post hoc test.