3.

Protease activity of Leishmania­(V.)­braziliensis extracts in the presence and absence of compounds. The activity was evaluated in 10 mM Tris–HCl pH 7.5 (A) and 10 mM sodium acetate buffer pH 5.5 containing 1 mM dithiothreitol (B). The x-axis shows the experimental conditions analyzed: 0.3 μM aprotinin (Apr), 10 μM E-64, 0.4 mM of compounds (TMC, 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, 3i, and 3j). The results are shown on the y-axis as relative fluorescence units per minute per microgram of protein (RFU × min^–1 × μg of protein^–1) and are expressed as the mean ± standard error of three independent experiments performed in triplicate. Differences between experimental groups and the solvent control (5.0% DMSO used to dilute the compounds), which represented 100% of enzyme activity (control). Data were analyzed by one-way ANOVA followed by Dunnett’s multiple comparisons test, with each treatment group compared with the control group. Statistically significant differences are indicated as (*) p < 0.05, (***) p < 0.001, and (****) p < 0.0001.