Figure 4.

Activity of 33 DHB compounds against B. malayi microfilariae and adults. (A) Primary screen: assessment of B. malayi mf motility (5 point scoring system) after 6 days of continuous exposure to 35 test compounds screened at 10 μM in triplicate. Ivermectin (50 μM) was the positive control. (B) Confirmatory mf motility and (C) metabolic activity screening of 15 active compounds identified in (A) and 5 inactive compounds (10 μM in triplicate). (D, E) EC₅₀ assays of active compounds 1 and 14 on B. malayi microfilarial metabolic activity after 6-day continuous exposure. Metabolic activity (C–E) was assessed by colorimetric MTT assay; data are optical density of mf extracts measured at 490 nm. (F) Effects on adult female B. malayi motility and (G) metabolic activity following 14 days of continuous exposure to 1 or 14 (10 μM). Flubendazole (10 μM) was used as a positive control in the assay. Data plotted is mean ± SD of 3 replicates (A–E) median and range of 6 replicates (F) and mean ± SEM of 9–11 replicates (G). Significant differences were determined by one-way ANOVA with Holm–Sidak multiple comparisons test (A–C and G) or Kruskal–Wallis with Dunn’s multiple comparisons test (F). Significance is indicated ****P < 0.0001, ***P < 0.001, **P < 0.01, and *P < 0.05.