| Popis: |
Helminth parasites are able to regulate the host’s defense mechanisms in order to prevent their expulsion or killing and these are characterized by chronic immunosuppression and reduced pathology. Hence, any combined therapy would take advantage of the synergistic action of a drug and a natural compound, which exert immunomodulatory as well as antiparasitic activities. To date, only a few natural compounds with defined molecular structure and well-described biological and medicinal activities have been investigated as having also an anthelmintic effect. In this chapter, after a brief introduction to key features of immunosuppression and host pathology, anthelmintic and immunomodulatory activities of artemisinins, genistein, curcumin, and tannins are described with some insight into selective toxicity to pathogens and cancer cells, but very low toxicity to the normal cells in the hosts. The host-protecting effect of a natural compound with antioxidant and antifibrotic activities in reducing the host pathology, thus, contributing to the elevated drug efficacy, is also highlighted in this chapter. The focus is on phenolic compounds paeoniflorin and silymarin, so far examined in flatworm infections, and the description of several molecular mechanisms underlying the above beneficial effects is provided. Regarding immunomodulatory activity of all phenolic compounds reviewed, the direction to selected subsets of immune cells toward the immunological balance depends on the type of disease. |
