In vitro efficacy of aqueous plants extracts in the control of gastrointestinal nematodes of cattle.
Fonseca L. D., Vieira T. M., Lázaro S. F., Silva M. L. F., Ferreira A. V. de P., Bastos G. A., Morais-Costa F., Martins E. R., Duarte E. R.
Author Affiliation: Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo (FZEA-USP), Pirassununga, SP, Brazil.
Acta Scientiae Veterinariae 42 :1216
Abstract : A study was conducted to evaluate the in vitro efficacy of plant aqueous extracts in the inhibition of larval development assay (ILDA) and inhibition of hatchability assay (IHA) of gastrointestinal nematodes of cattle. The ILDA was performed by quantitative coproculture, with aqueous extracts of the leaves of Acrocomia aculeata, Anacardium occidentale, Caryocar brasiliense, Cymbopogon citratus, Mangifera indica var. Ubá and Musa spp. cv. Prata-anã on the concentration of 100 mg/mL. The aqueous C. brasiliense leaf and fruit peel extracts at 15.00, 7.50, 3.75 and 1.88 mg/mL were evaluated for IHA. The controls of assays were ivermectin (16 µg/mL) and levamisole phosphate solution (15 mg/ml), respectively, and water in both tests. Efficiencies were calculated and count data submitted to analysis of variance and the means were compared by Tukey test (P0.01). The levels of condensed tannins from aqueous extracts of the leaves and fruit peels of C. brasiliense were quantified. In ILDA, the extract of C. brasiliense showed 91.29% efficacy and was not significantly different from ivermectin (P0.01). The other extracts did not obtain satisfactory efficacy and were similar to water (P0.01). In IHA the efficacy was over 90% for the extracts of the fruit peels and the three largest concentrations did not differ with levamisole phosphate. The greater efficacy of leaf extract was 89.15%, to 15.00 mg/mL. The LC50 and LC90 were 0.37 and 1.70 mg/mL for the aqueous extract of the fruit peels, respectively, and 0.043 and 15.88 mg/mL for the aqueous extract of leaves of C. brasiliense. The levels of condensed tannins expressed as cyanidin chloride were 2.7 and 8.3 mg/g of extract for crude extract of the fruit peels and leaves of C. brasiliense, respectively. The results shows that of the extracts evaluated only the leaves and fruit peels of C. brasiliense have great potential in the control of gastrointestinal nematodes of cattle. In the case of C. brasiliense, it is believed that anthelmintic potential is consequence of association between condensed tannins and other metabolites, since the extract of the fruit peels showed better efficacy and content of condensed tannins was higher in the leaf extract.