Ellagitannins Inhibit the Exsheathment of Haemonchus contortus and Trichostrongylus colubriformis Larvae: The Efficiency Increases Together with the Molecular Size.

Maarit Karonen,Lucie Legroux,Marica T Engström,Jussi Suvanto,Jeffrey R Ahern,Juha-Pekka Salminen,Hervé Hoste,Jari Sinkkonen

doi:10.1021/acs.jafc.9b06774

Abstract

Worldwide, parasitic gastrointestinal nematodes continue to threaten animal health, welfare, and production in outdoor breeding systems of small ruminants. For more than 50 years, the control of these parasitic worms has relied on the use of commercial synthetic anthelmintics. However, anthelmintic resistance in worm populations is nowadays widespread and requires novel solutions. The use of tannin-rich plants has been suggested as an alternative to synthetic anthelmintics to control gastrointestinal nematodes. The majority of previous studies have focused on the activity of proanthocyanidins (syn condensed tannins), and less is known about ellagitannins. In this study, the effects of 30 structurally unique ellagitannins on the exsheathment of third-stage infective larvae were examined on Haemonchus contortus and Trichostrongylus colubriformis by the in vitro larval exsheathment inhibition assay. Ellagitannins were found to be promising natural anthelmintics as they showed direct inhibition on larval exsheathment for both nematode species. In general, ellagitannins were more efficient at inhibiting the exsheathment of H. contortus larvae than those of T. colubriformis. The efficiency of inhibition increased as the degree of oligomerization or the molecular weight of the ellagitannin increased. Otherwise, we found no other structural features of ellagitannins that significantly affected the anthelmintic activity on the third-stage infective larvae. The effective concentrations were physiologically relevant and should be achievable in the gastrointestinal tract also in in vivo conditions.

Highlights

Parasitic nematodes of the gastrointestinal tract remain a major threat to small ruminant health, welfare, and production.[1,2] Broad-spectrum anthelmintic drugs with varying chemical structures have been used for more than 50 years for eliminating worms from hosts
This study aims at further exploring the potential anthelmintic properties of ETs against gastrointestinal nematode species and the key stages of the life cycle of gastrointestinal nematodes
The current study focused on the third-stage infective larvae by investigating the anthelmintic activities of 30 individual ETs against two main parasitic nematodes species

Summary

Introduction

Parasitic nematodes of the gastrointestinal tract remain a major threat to small ruminant health, welfare, and production.[1,2] Broad-spectrum anthelmintic drugs with varying chemical structures have been used for more than 50 years for eliminating worms from hosts. Reports on multiresistant isolates are increasing.[6] In cattle and horses, the situation is not yet so severe, but they have nematodes resistant to multiple anthelmintic classes.[3] alternative, sustainable options are urgently needed to ensure sheep and goat welfare and health. There is a clear need to address the increasing societal demands of consumers to reduce the use of synthetic chemicals in various farming systems This is illustrated by the demand and development of organic livestock farming systems and products, which do not use synthetic anthelmintics but require novel alternative options to reduce worm infection

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