Techniques to screen plant extracts for their nematicidal (anthelmintic) effects
New research ideas and plans

Dr I. Mueller-Harvey (University of Reading) visited Dr Herve Hoste, INRA-IHAP, ENVT, Toulouse from 23rd until 28th May 2011.

This STSM visit addressed the following objectives:

Objective. 1: To mine data from a recent research project in order to write joint publications. It is expected that this will generate at least one joint publication which will acknowledge this COST Action. Dr H. Hoste, Dr F. Manolaraki and me discussed the results of two manuscripts plus data for a third manuscript:

  • Manolaraki F., Regos I., Treutter D., Stringano E., Mueller-Harvey I., Caussade Semences, Hoste H. Environmental factors influence the in vitro anthelmintic activity of sainfoin (Onobrychis viciifolia).
  • Ojeda-Robertos, N., Manolaraki, F., Theodoridou, K., Aufrère, J., Halbwirth, H., Stich, K., Regos, I., Treutter, D., Mueller-Harvey, I., Hoste, H. Conservation methods (fresh, hay, silage) affect the in vitro anthelmintic activity of sainfoin: possible role of flavonoid glycosides and aglycosides.

Objective. 2: To familiarise myself with the laboratory techniques, which Dr H. Hoste has set up and continues to develop and which can be used to screen plant extracts for their nematicidal (anthelmintic) effects against parasitic nematodes in small ruminants. This is necessary for maximising results from the proposed, new interdisciplinary research. Dr Hoste explained in detail the anthelmintic assays that are currently being used in his laboratory (larval development assay, migration assay, exsheathment assay, mucosal direct challenge assay, adult worm motility inhibition assay). In addition, he outlined his ideas for developing new assays that will probe anthelmintic effects against adult worms.

Objective. 3: To generate research ideas and plan new experiments at the interface between plant chemistry and veterinary science. Our discussions focused on planning a series of experiments for testing contrasting willow tannins and for investigating any synergistic effects. These experiments will be carried out by two EU funded postdoctoral researchers and a PhD student starting in 2011. We discussed a series of novel experiments that will test which tannin features possess anthelmintic activities against the different stages in the parasitic nematode life cycle (L3 to L5). We developed ideas for screening a commercial Lotus corniculatus germplasm collection (Jouffray-Drillaud).

Objective. 4: To prepare joint EU and bi-lateral grant applications. Dr Hoste and I met with Dr Celine Mathieu (ENSIACET/Laboratoire de Chimie Agro-Industrielle, Toulouse) to discuss a range of researchable questions and experiments that could form the basis for new grant applications. These will target the better utilisation of agro-industrial byproducts, in order to harvest and/or preserve their tannins for controlling parasitic worms. Dr Mathieu’s laboratory has a suite of instruments for extracting and processing of plant materials (microwave, ultrasound, thermal induction, 100 l reactor-evaporator, a twin-screw extrusion system for preparing fibres and extracts, a pelleting system that can operate at different temperatures and pressures, macerators and Soxhlet instruments plus a wide range of HPLC, LC-MS and LC/GC-MS-MS instruments). We established that Soxflo, HPLC-GPC, Counter Current Chromatography and high-field NMR instruments at the University of Reading would be complementary to Dr Mathieu’s extraction facilities. In addition, we made contact with Professor Farid Chemat, who heads the Green Extractions Laboratory at the University of Avignon. His laboratory conducts research into environmentally friendly extraction systems at the laboratory to pilot scale. To conclude, this grouping of researchers and laboratories is well placed to design new extraction systems for adding value to agro-industrial by-products, by processing/preserving the by-products or by extracting anthelmintic compounds. We formulated a plan that includes additional scientific disciplines, such as parasitic plant nematodes, animal nutrition, toxicology, immunology and chemical analysis for a new EU application. In addition, we planned several dissemination activities for the recently completed EU HealthyHay project, e.g. - Rapid screening by NIR spectroscopy of sainfoin for AH properties - FAO-CIHAEM meeting - A handbook on sainfoin Report prepared by Dr I. Mueller-Harvey, on 24 June 2011.

STSM Irene Mueller Harvey
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