|Chagas, Ana Carolina|
Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/4/2011
Publication Date: 7/4/2011
Citation: Katiki, L.M., Chagas, A., Bizzo, H.R., Ferreira, J.F., Amarante, A. 2011. Anthelmintic activity of Cymbopogon martinii, Cymbopogon schoenanthus and Mentha piperita essential oils evaluated in four different in vitro tests. Veterinary Parasitology. 183:103-108. Interpretive Summary: Nematode resistance to current commercial drugs used for the control of livestock parasites is of worldwide concern. Gastrointestinal nematodes are a major parasitic hindrance to the economic development of ruminant grazing systems around the world. The essential oils of the aromatic plants lemon grass (two species) and mint have an established value for the aromatic oils industry around the world but have not been evaluated for their potential anthelmintic activity against a gastrointestinal nematode of goats and sheep. We have used laboratory assays based on the ability of these oils to impair nematode egg hatching (EHA), larval development (LDA), larval feeding (LFIA), and larval molting (LEA); all four being vital for nematode life cycle completion, feeding and survival inside of the host animal. One of the species of lemon grass was the best in affecting the adult nematodes used in those four laboratory tests described above, while both the oils of the other lemon grass species and mint had little or no effect on the nematodes in any of the four assays used for testing. The most active essential oil was rich in the terpenic compounds geraniol (62.5%), geranial (12.5%), and neral (8,2%), believed to be responsible for a concerted action against the adult nematodes used in the laboratory tests. These results indicate that these four laboratory assays can be an efficient way to estimate anthelmintic efficacy of plant products and that certain species of lemon grass are potential sources of anthelmintic compounds. Small farmers in Appalachia, and elsewhere, who depend on small ruminants as their major source of animal protein and cash flow would benefit from affordable and efficient ways to control livestock parasitic nematodes that hinder the establishment and profitability of grazing ruminant systems.
Technical Abstract: Anthelmintic resistance is a worldwide concern in small ruminant industry and new plant derived compounds are being studied for their potential use against gastrointestinal nematodes. Mentha piperita, Cymbopogon martinii and Cymbopogon schoenanthus essential oils were evaluated against developmental stages of trichostrongylids from sheep through the Egg Hatch Assay (EHA), Larval Development Assay (LDA), Larval Feeding Inhibition Assay (LFIA), and the Larval Exsheathment Assay (LEA). The major constituents of the essential oils, quantified by gas chromatography for M. piperita oil was menthol (42.5%), while for C. martinii and C. schoenanthus the main component was geraniol (81.4% and 62.5%, respectively). In all in vitro tests C. schoenanthus essential oil had the best activity against ovine trichostrongylids followed by C. martini, while M. piperita presented the least activity. Cymbopogon schoenanthus essential oil had LC50 value of 0.05 µL/mL in EHA, 0.07 µL/mL in LDA, 0.01 µL/mL in LFIA, and 27.1 µL/mL in LEA. The anthelmintic activity of essential oils followed the same pattern in all in vitro tests, suggesting the in vivo evaluation of C. schoenanthus essential oil for its anthelmintic activity.