Free (epi) catechin, quercetin, (epi) gallocatechin, flavonol glycosides and condensed tannins were identified according to their molecular mass, characteristic product ions and retention times in extracts obtained from leaves and branches of Maytenus ilicifolia (Congorosa) by mass spectrometry. The in vitro anthelmintic activity against cattle gastrointestinal nematodes of Congorosa extract was determined using the Egg Hatch Inhibition Assay. Additionally, commercial quercetin, gallocatechin and epicatechin were evaluated. Although total phenolics, total tannins and condensed tannins contents were lower in branches extract than in leaves extract, the EC50 were 0.065 mg/mL and 0.890 mg/mL for branches and leaves extract, respectively. Moreover, the use of polyvinylpyrrolidone as a blocking agent of tannins, did not change significantly the EC50 for branches extract, but significantly changed for leaves extract. Quercetin and gallocatechin EC50 values were in the range 0.03-0.05 mg/mL and epicatechin showed 100% inhibition of the egg hatching process at 0.004 mg/mL.
Keywords: Maytenus ilicifolia; egg hatch inhibition assay; mass spectrometry; phenolic compounds; ruminant´s anthelmintic activity.