Impact of chemical structure of flavanol monomers and condensed tannins onin vitroanthelmintic activity against bovine nematodes

Abstract

SUMMARYPlants containing condensed tannins (CT) may have potential to control gastrointestinal nematodes (GIN) of cattle. The aim was to investigate the anthelmintic activities of four flavan-3-ols, two galloyl derivatives and 14 purified CT fractions, and to define which structural features of CT determine the anti-parasitic effects against the main cattle nematodes. We used in vitro tests targeting L1 larvae (feeding inhibition assay) and adults (motility assay) of Ostertagia ostertagi and Cooperia oncophora. In the larval feeding inhibition assay, O. ostertagi L1 were significantly more susceptible to all CT fractions than C. oncophora L1. The mean degree of polymerization of CT (i.e. average size) was the most important structural parameter: large CT reduced larval feeding more than small CT. The flavan-3-ols of prodelphinidin (PD)-type tannins had a stronger negative influence on parasite activity than the stereochemistry, i.e. cis- vs trans-configurations, or the presence of a gallate group. In contrast, for C. oncophora high reductions in the motility of larvae and adult worms were strongly related with a higher percentage of PDs within the CT fractions while there was no effect of size. Overall, the size and the percentage of PDs within CT seemed to be the most important parameters that influence anti-parasitic activity.

The role of condensed tannins in ruminant animal production: advances, limitations and future directions

“…Similar findings have been reported with cattle parasites. Condensed tannins composed predominantly of prodelphinidin reduced motility of L1 and adult stage Ostertagia ostertagi and Cooperia oncophora (Desrues et al, 2016).…”

“…However, Quijada et al (2015) and Desrues et al (2016) reported the opposite effect and suggested that variation in results is likely due to differences and difficulties in extraction and purification of CT, as well as differences in modes of action of different CT on different gastrointestinal nematode parasites. The mode of action of CT on gastrointestinal nematode parasites has not been entirely clarified.…”

Benefits of Condensed Tannins in Forage Legumes Fed to Ruminants: Importance of Structure, Concentration, and Diet Composition

“…These include inhibition of L3 migration and L4 motility with Ascaris suum, as well as L1 feeding inhibition, adult motility assays of Ostertagia ostertagi and Cooperia oncophora, and larval exsheathment inhibition of Haemonchus contortus and Trichostrongylus colubriformis of L3 larvae (Brunet and Hoste 2006;Quijada et al, 2015;Desrues et al, 2016a;Ramsay et al, 2016). These include inhibition of L3 migration and L4 motility with Ascaris suum, as well as L1 feeding inhibition, adult motility assays of Ostertagia ostertagi and Cooperia oncophora, and larval exsheathment inhibition of Haemonchus contortus and Trichostrongylus colubriformis of L3 larvae (Brunet and Hoste 2006;Quijada et al, 2015;Desrues et al, 2016a;Ramsay et al, 2016).…”

“…The average size of CTs in a polymeric mixture (mDP value) can also affect their antiparasitic activity, with larger polymers being more potent against exsheathment of H. contortus L3 and larval feeding of O. ostertagi and C. oncophora L1 larvae in vitro Desrues et al, 2016a). However, PD-rich plants tend to have CTs with high mDP values and high CT concentrations Laaksonen et al, 2015;Mueller-Harvey et al, unpublished data, 2016), confounding our understanding of CT structure-activity relationships.…”

“…Taken together, these observations could explain why PDs, which generally have larger mDP values than PCs, have better anthelmintic properties Kommuru et al, 2014Kommuru et al, , 2015. Given the low uptake (bioavailability) of polymeric CTs in mammalian tissues in comparison with monomeric flavonoids (Li and Hagerman, 2013), it would be worth exploring whether the internal tissue damage arises from the CTs or from other compounds that may be present in plant extracts (Brunet and Hoste, 2006;Williams et al, 2015;Klongsiriwet et al, 2015;Desrues et al, 2016a;Mengistu et al, 2017). leaves (Martínez-Ortíz-de-Montellano et al, 2013;Kommuru et al, 2015).…”