In vitro effects of aqueous extract from Maytenus senegalensis (Lam.) Exell stem bark on egg hatching, larval migration and adult worms of Haemonchus contortus

Abstract

Background: Maytenus senegalensis is a common shrub which is scattered in tropical Africa. Different parts of this plant have been reported to be useful in traditional medicine against gastrointestinal disorders and intestinal worms. This study evaluated the anthelmintic activity of the aqueous stem bark extract of M. senegalensis using egg hatch assay (EHA), larval migration inhibition assay (LMIA) and adult worms' motility inhibition assay (AMIA). Results: On EHA, the extract concentrations tested resulted in a significant (p<0.01) inhibition of egg hatching in concentration-dependent manner and ranged between 31.86% at 75 μg.mL-1 to 54.92% at 2400 μg.mL-1 after a 48 h post-exposure with eggs. For the LMI assays, the aqueous extract of M. senegalensis showed a significant (p<0.05) inhibition of larval migration in a concentration-dependent manner. The highest concentration used (2400 μg.mL-1) showed a 37.77% inhibition. The use of polyvinyl polypyrrolidone (PVPP) indicated that tannins and flavonoids were partly involved in the effect since the larval migration was inhibited by 15.5%, but other biochemical compounds were also implicated. On AMIA, M. senegalensis was associated with a reduced worm motility after a 24 h post exposure compared to phosphate buffered saline as control (p<0.05). By this time 66.66% of the worms' were found immotile or dead in the wells containing plant extract at 2400 μg.mL-1. The Phytochemical analysis of aqueous extract of M. senegalensis by HPLC-ESI-MSn detected the presence of proanthocyanidins (20%) and flavonoids (>50%). Conclusions: These in vitro results suggest the presence of some anthelmintic properties in M. senegalensis extract, which is traditionally used by small farmers in west and central Africa. These effects may be due to the flavonoids and proanthocyanidins present in the extract and need to be studied under in vivo conditions.