Two in vitro anthelmintic assays of four Paraguayan medicinal plants for proof of concept of the role of polyphenols in their biological activities and LC-HRMS analysis.

ETHNOPHARMACOLOGICAL RELEVANCE: Gastrointestinal nematodes (GIN) control in small ruminants has relied on the systematic use of synthetic anthelmintics (AH), their effectiveness has been progressively decreasing due to the rise and diffusion of anthelmintic resistances. The most prevalent genera affecting small ruminants were Haemonchus spp., and Trichostrongylus spp. The investigation of new anthelmintics in plants is a highly studied option, especially when it is linked to ethnobotanical knowledge and phenolic compounds. THE AIMS OF OUR STUDY: Four medicinal plants mentioned in traditional medicine were selected to evaluate their anthelmintic proprieties at different stages of the life cycle of GIN, namely: Kyllinga odorata Valh., Cassia occidentalis L., Artemisia absinthium L, and Verbena litoralis Kunth and to explore the role of polyphenols in the AH activity. MATERIALS AND METHODS: To evaluate the anthelmintic activity in this study, two models of GIN species, namely Haemonchus contortus (Hc) and Trichostrongylus colubriformis (Tc) were selected and tested on two in vitro assays: 1) Larval Exsheathment Inhibition Assay (LEIA) and, 2) Egg Hatch Assay (EHA). To explore the role of tannins and polyphenols in AH activity by comparing the effects of LEIA and EHA with or without polyvinylpolypyrrolidone (PVPP) and to characterize the phytochemical composition of the most active plants using ultra-high performance liquid chromatography (UHPLC) coupled with high-resolution mass spectrometry (HRMS). RESULTS: C. occidentalis exhibited the highest activity on LEIA (EC50 = 250.42-41.80 µg/mL) and A. absinthium on egg hatching processes (EC50 = 121.70-137.34 µg/mL) in both species of GIN. The inhibition in the development of eggs was from 67.70% to 96.36% on H. contortus, and from 78.87% to 99.65% on T. colubriformis. At the maximal dose, Additionally, it was observed that the AH on eggs varies according to the GIN species: on H. contortus the extracts tested blocked the formation of larvae Ovicidal Effect (% higher OE) and on T. colubriformis they blocked the appearance of L1 larvae, Larvae Failing Eclosion (% higher LFE). After PVPP, a reduction in AH activity on LEIA and EHA was noted, especially with C. occidentalis (87.20-67.00% of larvae exsheathment, (p < 0.05) and 40.51-24.96% of egg hatching, (p > 0.05) of both parasite species. Nine putative features were identified using HRMS and MS/MS after addition of PVPP. CONCLUSIONS: The present study demonstrated that C. occidentalis, A. absinthium, and K. odorata, which parts have been traditionally used as medicinal plants are a valuable source of active compounds with anthelmintic activity. The medicinal use of these plants against GIN parasites was proven by in vitro analysis. Therefore exploration of the secondary metabolites of these plant extracts and testing of isolated fractions of active compounds under in vivo experiments are planned and represent a specific challenge for alternative drug research. Regarding the PVPP, in this study we hypotheses about the standard doses it was not able to completely absorb the polyphenols of extracts of K. odorata, C. occidentalis, and A. absinthium, which would lead to more studies to evaluate the role of this product in the absorption of phenolic compounds.

Use of agro-industrial by-products containing tannins for the integrated control of gastrointestinal nematodes in ruminants.

Previous studies have illustrated that different bioactive legume fodders containing condensed tannins might represent one of the options for integrated sustainable control of gastrointestinal nematodes (GIN) in ruminants, which may help address the worldwide development of resistance to synthetic anthelmintics. More recently, impetus has been given to assess the potential antiparasitic activity of less conventional resources, represented by different agro-industrial by-products (AIBPs). This review presents in vitro and in vivo results obtained with a range of tannin-containing AIBPs of various geographical and botanical origins, namely AIBP of nuts, temperate and tropical barks, carob, coffee and cocoa. They tend to confirm the "proof of concept" for their antiparasitic effects and also for other aspects of ruminant production in an agro-ecological context. Socio-economic aspects of the exploitation of such non-conventional resources are also discussed as potential models of the circular economy, by using waste. The different modes of use of these resources are presented in this review, as well as strengths, weaknesses, opportunities, and threats (SWOT) analyses to illustrate the advantages and limitations of on-farm use.

TITLE: Utilisation de sous-produits agro-industriels contenant des tanins pour le contrôle intégré des nématodes gastro-intestinaux chez les ruminants. ABSTRACT: Plusieurs études antérieures ont illustré le fait que des légumineuses bioactives contenant des tannins condensés peuvent représenter une des alternatives à intégrer avec d'autres options pour une maitrise durable des nématodes gastro-intestinaux en réponse au développement constant et à l'expansion continue à l'échelle mondiale des résistances aux anthelminthiques de synthèse. Des recherches plus récentes se sont intéressées au potentiel d'application de ressources moins conventionnelles que représentent des coproduits agroindustriels (CPAI). Cette revue vise à présenter des résultats in vitro et in vivo obtenus avec une gamme de CPAI d'origines géographiques et botaniques diversifiées (coproduits de l'industrie des noix, du bois (en régions tempérées et tropicales), du caroubier, du café et du cacao). Ces résultats ont confirmé la preuve de concept pour les effets antiparasitaires, et aussi pour d'autres volets de la production des ruminants dans un contexte agro écologique de l'élevage. Par ailleurs, les aspects socio-économiques d'exploitation de ces ressources, considérées jusqu'à présent comme des déchets, dans un modèle de circuits courts sont aussi évoqués. Les avantages et inconvénients des différentes modalités d'exploitation des CPAI sont aussi discutés dans le cadre d'une analyse SWOT.