In Vitro Anthelmintic Activity of Saponins Derived from Medicago spp. Plants against Donkey Gastrointestinal Nematodes

With the aim to find new effective natural compounds for the control of nematodes, the in vitro anthelminthic properties of purified 1% saponins showing different chemical compositions and derived from Medicago sativa (MS), Medicago arborea (MA), Medicago polymorpha cultivar ‘Santiago’ (MPS), M. polymorpha cultivar ‘Anglona’ (MPA), and 1% prosapogenins from M. sativa (MSp), were evaluated and compared. As a source of nematode eggs, pooled fresh fecal samples taken from dairy donkeys naturally infected by gastrointestinal nematodes were used. From fecal samples, eggs were recovered, suspended in deionized water, and used immediately in the bioassay (egg hatch test). The activity of the tested compounds was compared to positive (0.1% thiabendazole) and negative (deionized water and 1% DMSO) controls. All experiments were repeated in triplicate and the obtained data were statistically analyzed. All the tested plant compounds caused a significant (p < 0.05) inhibition of nematode egg hatching (>80%). Moreover, all saponins and prosapogenins showed in vitro anthelmintic properties statistically comparable to that of the reference drug (p < 0.05), except for MPS extract. Obtained results showed that the different Medicago saponins evaluated in this study possess high anthelmintic properties against gastrointestinal nematodes of dairy donkeys, although to a different extent depending on their composition.