Dalbergia palo-escrito (Fabaceae) contains phenolic compounds with anthelmintic effect on the parasitic nematode Haemonchus contortus.

This study evaluated the anthelmintic activity of a hydroalcoholic extract (HA-E) from Dalbergia palo-escrito aerial parts against Haemonchus contortus using a bioguided approach. The egg hatching inhibition (EHI) assay was conducted to determine activity. The HA-E was partitioned into an aqueous fraction (Aq-F) and an ethyl acetate fraction (EtOAc-F). The EtOAc-F was fractioned by column chromatography into seven subfractions (PeF1 to PeF7). HA-E and EtOAc-F achieved 100% EHI at 50 and 1.0 mg/mL, respectively. Subfractions PeF1, PeF3, and PeF4a exhibited strong activity, with EC90 values of 0.32, 0.15 and 0.23 mg/mL. From PeF4, a precipitate (PeF4p) and its mother liquor (PeF4a) were obtained. NMR analysis identified caviunin in PeF4p, but it did not show anthelmintic activity. PeF4a contained a mixture of linear alcohols, terpenes, hydroxybenzoic acids and isoflavones. These results highlight D. palo-escrito as a valuable natural source of compounds with ovicidal activity against H. contortus eggs.