Phenolic Acids and Flavonoids from Pithecellobium dulce (Robx.) Benth Leaves Exhibit Ovicidal Activity against Haemonchus contortus .

Pithecellobium dulce (Robx.) Benth is an arboreal legume used in traditional medicine for the treatment of several ailments, including a number of intestinal disorders, and as a natural deworming. The objective of this study was to evaluate the ovicidal activity of a hydroalcoholic extract (HA-E) and its fractions (aqueous, Aq-F and organic, EtOAc-F) from P. dulce leaves, as well as subfractions (C1F1-C17) obtained from EtOAc-F against Haemonchus contortus eggs. The HA-E, Aq-F, and EtOAc-F were assessed at 0.03-5.00 mg/mL and subfractions (C1F1-C17) were assessed at 0.06-1.00 mg/mL. The HA-E and Aq-F showed an ovicidal activity close to 100% at 2.5 mg/mL, and EtOAc-F displayed the highest anthelmintic effect (100% at 0.25 mg/mL). Meanwhile, the sub-fractions with the highest ovicidal effect were C1F6, C1F9, C1F10, C1F11, and CIF13. The main compounds identified in the most active fractions (C1F9, C1F11, and C1F13) were kaempferol ( 1 ), quercetin ( 2 ), coumaric acid ( 3 ), ferulic acid ( 4 ), luteolin 7-O-rhamnoside ( 5 ), quercetin 3-O-rhamnoside ( 6 ), and a caffeoyl derivate (NI). The results indicate that P. dulce leaves exhibit a potent anthelmintic activity and contain bioactive compounds able to inhibit egg hatching in H. contortus . Therefore, this plant could be used for the control of gastrointestinal nematodes in small ruminants.