The extract was hydrolysed to analyse the aglycones by gas chromatography (Fig. 2), which verified

MK-8776 supplier two compounds comprised the majority of the fraction. The GC–MS analysis enabled characterise the compounds as tigogenin and hecogenin, which demonstrated retention times at 6.3 min (Peak a) and 8.1 min (Peak b), respectively. The liquid waste of A. sisalana was effective against eggs, larvae and adults worms of the gastrointestinal nematodes in vitro ( Domingues, 2008 and Silveira, 2009). The lack of similarity between the in vitro and in vivo tests can be attributed to several factors. In the in vitro tests, the extracts were in direct contact with the parasites. Furthermore, the concentrations of the potentially BIBW2992 mouse active substances in the extract do not always correspond to the bioavailability in vivo ( Githiori et al., 2006). Another possibility is the biotransformation of these compounds within the gastrointestinal tract of the animal, which may lead to a loss of biological activity ( Athanasiadou and Kyriazakis, 2004). The bioavailability of plants constituents can be modified by rumen microorganism, which may explain to the low efficacy of

AESW against NGIs. In lambs that received an intra-ruminal administration of saponins from Yucca schidigera was observed a rapid hydrolysis in the rumen and a large amount of free sapogenins in the contents of omasum and abomasums ( Flaoyen Idoxuridine et al., 2002). The effectiveness of levamisole against nematodes in the positive control group was less than 90%. Furthmore, the FEC of one goat of this

group remained high eleven day after the treatment, which led to death of this animal. These findings may indicate the resistance of these parasites. Such resistance has been previously reported in goats and sheep in Brazil (Melo et al., 2003). The oral treatment of goats with AESW did not cause clinical changes that suggested toxicity. The low intestinal absorption of orally administered saponins may be responsible for their reduced toxicity (Price et al., 1987). In addition, the sisal extract did not influence (0.9 g/kg) the clinical, haematological, biochemical and histopathological parameters of the goats (Domingues, 2008). However, saponins may interfere with rumen fermentation, cause an increase in pH, lead to a decrease in the protozoa population and promote the concentration of volatile fatty acids (Santoso et al., 2007). The haemoglobin level after treatment was higher in group II (positive control) compared to the other groups, which may have been due to a lower level of parasite infection. It is possible that there was an inverse correlation between FECs and haemoglobin (Farias et al., 2002). However, saponins usually cause haemolysis due to their ability to form complexes with sterols in cell membranes and promote cell lysis. in vitro studies investigating the effect of steroidal saponins from A.