title: The anthelmintic efficacy of natural plant cysteine proteinases against the rat tapeworm Hymenolepis diminuta in vivo.
abstract: Hymenolepis diminuta is a natural parasite of the common brown rat Rattus norvegicus, and provides a convenient model system for the assessment of the anthelmintic activity of novel drugs against cestodes. The experiments described in this paper indicate that treatment of rats infected with H. diminuta with a supernatant extract of papaya latex, containing a mixture of four cysteine proteinases, was moderately efficacious, resulting in a significant, but relatively small, reduction in worm burden and biomass. However, faecal egg output was not affected by treatment. In our experiments these effects were only partially dose-dependent, although specific inhibition by E-64 confirmed the role of cysteine proteinases as the active principles in papaya latex affecting worm growth but not statistically reducing worm burden. Data collected for a further 7 days after treatment indicated that the effects of papaya latex supernatant on worm loss and on worm growth were not enhanced. Our findings provide a starting point for further refinement in formulation and delivery, or assessment of alternative natural plant-derived cysteine proteinases in efforts to develop these naturally occurring enzymes into broad-spectrum anthelmintics, with efficacy against cestodes as well as nematodes.
authors.affiliation: School of Life Sciences, University of Nottingham, University Park,Nottingham,NG7 2RD,UK.
authors.forename: F
authors.initials: F
authors.lastname: Mansur
authors.affiliation: School of Life Sciences, University of Nottingham, University Park,Nottingham,NG7 2RD,UK.
authors.forename: W
authors.initials: W
authors.lastname: Luoga
authors.affiliation: Department of Infection and Immunity,University of Sheffield Medical School,Beech Hill Road,Sheffield,UK,S10 2RX.
authors.forename: D J
authors.initials: DJ
authors.lastname: Buttle
authors.affiliation: School of Life Sciences, University of Nottingham, University Park,Nottingham,NG7 2RD,UK.
authors.forename: I R
authors.initials: IR
authors.lastname: Duce
authors.affiliation: School of Life Sciences, University of Nottingham, University Park,Nottingham,NG7 2RD,UK.
authors.forename: A
authors.initials: A
authors.lastname: Lowe
authors.affiliation: School of Life Sciences, University of Nottingham, University Park,Nottingham,NG7 2RD,UK.
authors.forename: J M
authors.initials: JM
authors.lastname: Behnke
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D029441:Carica / Q000737:chemistry; D057056:Cysteine Proteases / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D006925:Hymenolepiasis / Q000188:drug therapy / Q000662:veterinary*; D048190:Hymenolepis diminuta / Q000187:drug effects*; D008297:Male; D010270:Parasite Egg Count; D059208:Parasite Load; D010936:Plant Extracts / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D010940:Plant Proteins / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology; D051381:Rats; D012376:Rodent Diseases / Q000188:drug therapy*; D016896:Treatment Outcome
chemical_list: D000871:Anthelmintics; D010936:Plant Extracts; D010940:Plant Proteins; D057056:Cysteine Proteases