Anthelmintic Activities against Haemonchus contortus or Trichostrongylus colubriformis from Small Ruminants Are Influenced by Structural Features of Condensed Tannins

Abstract

Plants containing condensed tannins (CTs) may hold promise as alternatives to synthetic anthelmintic (AH) drugs for controlling gastrointestinal nematodes (GINs). However, the structural features that contribute to the AH activities of CTs remain elusive. This study probed the relationships between CT structures and their AH activities. Eighteen plant resources were selected on the basis of their diverse CT structures. From each plant resource, two CT fractions were isolated and their in vitro AH activities were measured with the larval exsheathment inhibition assay, which was applied to Haemonchus contortus and Trichostrongylus colubriformis. Calculation of mean EC50 values indicated that H. contortus was more susceptible than T. colubriformis to the different fractions and that the F1 fractions were less efficient than the F2 ones, as indicated by the respective mean values for H. contortus, F1 = 136.9 ± 74.1 μg/mL and F2 = 108.1 ± 53.2 μg/mL, and for T. colubriformis, F1 = 233 ± 54.3 μg/mL and F2 = 166 ± 39.9 μg/mL. The results showed that the AH activity against H. contortus was associated with the monomeric subunits that give rise to prodelphinidins (P < 0.05) and with CT polymer size (P < 0.10). However, for T. colubriformis AH activity was correlated only with prodelphinidins (P < 0.05). These results suggest that CTs have different modes of action against different parasite species.

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

“…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.…”

“…Like CT-protein interactions, variation in anthelmintic activity in response to different sources of CT is probably a structure-function relationship. Quijada et al (2015) demonstrated that CT composed predominately of prodelphinidin subunits had greater anthelmintic activity than those composed predominantly of procyanidin. This may explain why L. cuneata, a forage that produces CT composed predominately of prodelphinidin subunits (Naumann et al, 2015b), has demonstrated high anthelmintic efficacy in vivo (Shaik et al, 2006;Terrill et al, 2007;Terrill et al, 2009).…”

Galloylated proanthocyanidins from shea (Vitellaria paradoxa) meal have potent anthelmintic activity against Ascaris suum

“…Analysis of PA-fractions by thiolytic degradation Sephadex LH-20 was used to obtain three PA fractions from the aqueous acetone extract in order to test their efficacy against A. suum. With most plant materials, this fractionation scheme removes impurities and generates highly pure PA, especially for the F2-fraction, and also yields fractions with different mDP values, which is of particular interest for anthelmintic analysis when assessing their bioactivities (Novobilský et al, 2011;Williams et al, 2014;Quijada et al, 2015). The PA content and overall composition is described in Table 4 and the molar percentages of individual flavan-3-ol subunits within the PA fractions in Table 5 (see also Supplementary section).…”

Browse species from Ethiopia: role in methane reduction and nematode control in goats

“…The lower inhibition in D. angustifolia could be due to the absence of PDs in the PA. More potent inhibition of PA on the exsheathment in H. contortus and T. colubriformis in vitro were observed with a higher PD:PC ratio (Brunet and Hoste, 2006;Quijada et al, 2015). In C. tomentosa with the lowest PA concentration (0-4%) and M. angolensis lacking PA, L 3 exsheathment was blocked at 1200 µg/ml suggesting browse compounds other than PA are involved in the inhibition of L 3 exsheathment.…”

“…A marked reduction on H. contortus L 3 exsheathment in vitro has been associated with the PD monomers and with the galloyl derivatives of tannins (Brunet and Hoste, 2006). Quijada et al (2015) reported that the building units of PA and the polymer size influenced anthelmintic properties in in vitro larval exsheathment of H. contortus.…”