Papaya latex supernatant has a potent effect on the free-living stages of equid cyathostomins in vitro
| Autor: | Jane E. Hodgkinson, Jerzy M. Behnke, Laura E Peachey, Gina Pinchbeck, Faith Burden, J. B. Matthews |
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| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Latex Cuticle Cysteine Proteinase Inhibitors 03 medical and health sciences Cysteine Proteases In vivo Botany medicine Animals Food science Anthelmintic Ananas Incubation Strongylida Infections Anthelmintics chemistry.chemical_classification General Veterinary biology Carica Plant Extracts General Medicine 030108 mycology & parasitology biology.organism_classification In vitro Enzyme chemistry Larva Strongylida Parasitology medicine.drug |
| Zdroj: | VETERINARY PARASITOLOGY |
| ISSN: | 0304-4017 |
| DOI: | 10.1016/j.vetpar.2016.07.036 |
| Popis: | The control of equid gastrointestinal nematodes in developed countries, in particular the cyathostomins, is threatened by high levels of anthelmintic resistance. In recent years, there has been increasing interest in the evaluation of traditional ‘ethnoveterinary’ medicines as alternatives to chemical anthelmintics. The cysteine proteinases (CPs), a group of enzymes derived from fruits such as papaya (Carica papaya), pineapple (Ananas comosus) and figs (Ficus spp.), have shown good efficacy against adult stages of a range of parasitic nematodes, in vitro and in vivo. The efficacy of CPs against cyathostomins remains to be explored. In this study, the efficacy of a crude preparation of CPs, papaya latex supernatant (PLS), against the free-living stages of cyathostomins was evaluated using two in vitro tests, the egg hatch test (EHT) and the larval migration inhibition test (LMIT). It was demonstrated that PLS had a potent effect in the EHT, with EC-50 values in the range of 0.12–0.22 μM. At concentrations above 6.25 μM the eggs did not develop, below this concentration the L1 developed but they lost integrity of the cuticle upon hatching. These effects were inhibited by pre-incubation of PLS with the CP inhibitor L-trans-epoxysuccinyl- l -leucylamido-(4-guanidino butane) (E64), indicating that CPs were responsible for the anti-parasitic activity. A dose-dependent inhibition of migration of third stage larvae (L3) in the LMIT was demonstrated at higher concentrations of PLS, with EC-50 values in the range of 67.35–106.31 μM. Incubation of PLS with E64 prior to use in the LMIT did not reverse the anti-migratory effect, suggesting that CPs were not responsible for the reduced migration of cyathostomin L3 and that PLS also contains an additional active compound. This is the first report of PLS and/or CPs showing activity against the free-living stages of a parasitic helminth. In addition, it suggests that cyathostomins are highly sensitive to the effects of CPs and further evaluation of their efficacy against parasitic stages and in vivo are strongly indicated. |
| Databáze: | OpenAIRE |
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