Antischistosomal Potential of Animal-Derived Natural Products and Compounds

Abstract

Schistosomiasis is a neglected tropical disease that affects over 240 million people worldwide. Currently, praziquantel is the only drug recommended by the World Health Organization for treatment. However, cases of drug resistance have been reported, which indicates an urgent need for new therapeutics. In this context, natural compounds represent valuable sources of pharmacological substances. Plant-derived natural products have been greatly explored for their potential antischistosomal activity, while animal-derived compounds have received little attention. Recent advances in the biotechnology field allow the wide exploration of animal-derived compounds in drug discovery, which may represent a cost-effective option to find bioactive molecules also against Schistosoma mansoni and other parasites. This review highlights the research into animal-derived products and compounds that have already been tested against schistosomes. Phenotypic effects on schistosomes have been observed upon incubation with some of these substances, which may, therefore, represent possible candidates to be used in the development of new drugs. Overall, these studies advance the discovery of antischistosomal compounds by exploring a yet understudied natural resource. The present review also discusses the challenges of testing animal-derived products and provides examples of the experimental in vitro testing of different selected animal natural products against S. mansoni.

Keywords: animal natural products; antiparasitic activity; schistosomiasis.

Figure 1

Life cycle of Schistosoma spp. Image from the Centers for Disease Control and Prevention (CDC). Available at https://www.cdc.gov/dpdx/schistosomiasis/index.html, accessed on 29 December 2024.

Figure 2

Antischistosomal activity of animal-derived natural products. (A) Adult S. mansoni couples were treated for 72 h with crude products or purified compounds and motility was assessed by microscopy (Score 3, normal motility, down to Score 0, dead) at 24 h and 72 h. Four different animal-derived natural products were assayed: venom from saw-scaled viper Echis carinatus (E.c.) at 20 µg/mL; venom from the assassin bug Rhynocoris iracundus (R.i.) at 50 µg/mL; buprestin H, an acyl glucose derivative, from the European jewel beetle Chalcophora mariana (C.m.) at 40 µM; and the defensin scapularisin-6 from the black-legged tick Ixodes scapularis (I.s.) at 50 µM. As a positive control, 2 µM praziquantel was used. Means of two independent replicates. (B) Source organisms and representative images of adult worms treated for 72 h. Scale bar: 500 µm.