Anthelmintic activity of Annona crassiflora leaves against Haemonchus contortus: part 1: in vitro inhibition of the hatchability and larval development

We evaluated the activity of Annona crassiflora leaves against Haemonchus contortus resistant to albendazol. Aqueous (AE), ethanolic (EE) and ethyl acetate (EAE) extracts were produced and the predominant presence of flavonoids was observed in HPLC-DAD chromatograms. Initially we evaluated the larval development inhibition (LDI) of dry A. crassiflora leaf powder or its AE directly in fecal quantitative cultures. The efficacies of the extracts, with or without tannins, on egg hatching inhibition (EHI) were investigated reveling that the EE was the most effective (LC90 = 8.96 mg/mL). However, after tannin removal, AE showed the highest activity (LC90 = 4.27 mg/mL). In the LDI test, the LC90 of AE was < 6.25 mg/g of fecal culture and to leaf powder of leaves was 69.14 mg/g. High efficacies of AE and EE for EHI were detected and the tannins were not the main active metabolites. The anthelmintic potential of this plant could be attributed to association between flavonoids and other metabolites