Action of sisal (Agave sisalana, Perrine) extract in the in vitro development of sheep and goat gastrointestinal nematodes.

Active compounds from Agave sisalana with antiparasitic action against gastrointestinal nematodes (GINs) could be an alternative to diversify the range of parasite management methods in the livestock sector. The objective of this study was to evaluate the in vitro action of A. sisalana extract on the development of sheep and goat GINs. The extract, obtained from shredded sisal leaves, was utilized at various concentrations in the egg hatch test (EHT), larval development test (LDT), larval feeding inhibition test (LFIT) and adult motility test (AMT). The LC(50) and LC(95) in the EHT were 6.90 and 24.79 mg/mL, in the LDT were 0.041 and 0.067 mg/mL and in the LFIT were 0.053 and 0.24 mg/mL, respectively, showing a dose-dependent relationship. The development and feeding inhibition on L(1) were both 100% at a dose of 0.12 mg/mL. In the AMT there was 100% inhibition at 75 mg/mL after 24h of exposure. The extract of A. sisalana therefore demonstrated significant action on L(1) at 0.12 mg/mL. So, if part of the A. sisalana extract passes through the animal's gastrointestinal system, this material can have a significant effect on the parasites in the feces. This is an interesting approach because it can drastically reduce the pasture contamination as well as the infection of herds.

The anthelmintic effect of plant extracts on Haemonchus contortus and Strongyloides venezuelensis.

The indiscriminate use of anthelmintics has resulted in the establishment of parasite resistance. Thus, this study aimed to evaluate the in vitro antiparasitic effect of plant extracts on Haemonchus contortus in sheep and the in vivo effect on Strongyloides venezuelensis in Rattus norvegicus. The plant extracts from Piper tuberculatum, Lippia sidoides, Mentha piperita, Hura crepitans and Carapa guianensis, produced at different research institutions, were chemically analyzed and evaluated through the egg hatch test (EHT) and larval development test (LDT) in H. contortus. P. tuberculatum (150 and 250 mg kg(-1) of body weight) was evaluated for its anthelmintic action on R. norvegicus experimentally infected with S. venezuelensis. In the EHT, the LC(50) and LC(90) of the extracts were respectively as follows: 0.031 and 0.09 mg mL(-1) for P. tuberculatum, 0.04 and 0.13 mg mL(-1) for L. sidoides, 0.037 and 0.10 mg mL(-1) for M. piperita, 2.16 and 17.13 mg mL(-1) for H. crepitans and 2.03 × 10(-6) and 1.22 × 10(-12) mg mL(-1) for C. guianensis. In the LDT, the LC(50) and LC(90) were respectively: 0.02 and 0.031 mg mL(-1) for P. tuberculatum, 0.002 and 0.04 mg mL(-1) for L. sidoides, 0.018 and 0.03 mg mL(-1) for M. piperita, 0.36 and 0.91 mg mL(-1) for H. crepitans and 17.65 and 1890 mg mL(-1) for C. guianensis. The extract of P. tuberculatum showed the following substances: piperamides as (Z)-piplartine, (E)-piplartine, 8,9-dihydropiplartine, piperine, 10,11-dihydropiperine, 5,6 dihydropiperlongumine and pellitorine. The major compounds of the oils were thymol (76.6%) for L. sidoides, menthol (27.5%) for M. piperita and oleic acid (46.8%) for C. guianensis. Regarding the in vivo test, neither dose of P. tuberculatum caused any significant reduction (P>0.05) in worm burden and fecal egg counts compared with the control group. We conclude that the extracts of P. tuberculatum, L. sidoides and M. piperita have effective activity when tested in vitro, but the doses of the extract of P. tuberculatum have no effect when employed in in vivo tests.