Abstract
The activity of a novel enaminone derivative of 4-hydroxyquinoline, BDHQ, was screened for its effectiveness against murine schistosomiasis by electron microscopy and parasitologic studies. The correlation of these studies with serum levels of IFN-gamma and IgE is described. Two groups of 10 mice each were treated with different doses of BDHQ, and their results were correlated with the control and praziquantel (PZQ)-treated groups. Parasitologic study revealed significant reduction in mature worms and tissue egg loads in BDHQ- and PZQ-treated groups, whereas immature worms revealed significant reduction in BDHQ groups only. The group treated with a higher dose of BDHQ showed significant reductions in intestinal ova count when compared with the PZQ-treated group. Ultrastructural examination of the worm revealed significant degeneration of the spines and tegument in all treated groups, while the genital system was affected in BDHQ-treated groups only. BDHQ showed considerable effect on cellular activation where serum levels of IFN-gamma were significantly increased in comparison to control, while anti-soluble worm antigen preparation (SWAP) IgE was significantly increased in comparison to both the control and PZQ-treated groups. Ultrastructural examination revealed cellular activation in buffy coat and the liver in both the BDHQ- and PZQ-treated groups in comparison to the untreated one, whereas in the bone marrow and spleen, evidence of cellular activation was remarkable in the BDHQ-treated groups. In conclusion, BDHQ exhibits high levels of activity against adult and juvenile stages of these parasites, which may be due to its mixed cellular and humoral immunologic mechanisms, as demonstrated by the significant increase of serum levels of IgE and IFN-gamma shown on electron microscopy. Therefore, our results support the comparative advantage that BDHQ has over PZQ.