Procyanidin A2 in the Australian plant Alectryon oleifolius has anthelmintic activity against equine cyathostomins in vitro.

The research article focuses on how procyanidin A2, isolated from the Australian plant Alectryon oleifolius, demonstrates significant anthelmintic (anti-parasitic) activity against equine cyathostomins, a type of parasite in horses, presenting a potential alternative approach to controlling these parasites due to an increase in anthelmintic resistance.

Research Objective

• The aim of the study was to identify and isolate the bioactive compound(s) from the Australian plant Alectryon oleifolius, which was previously found to have an effect against cyathostomins, a kind of parasitic worm that affects horses. The researchers wanted to quantify the efficacy of this compound in vitro (in a controlled, outside-the-body environment).

Methodology

• The researchers used bioassay guided fractionation to isolate the component responsible for the anthelmintic activity. This process involves separating the plant extract into fractions and testing each one to identify which has the desired biological activity.
• The isolated compound, procyanidin A2, was then identified using 1D and 2D nuclear magnetic resonance spectroscopy and high performance liquid chromatography combined with mass spectrometry. These techniques allowed the researchers to determine the structure and composition of the compound.

Findings

• The compound procyanidin A2 was found to have significant anthelmintic activity in larval development assays. It completely inhibited the growth of the parasites from egg to third larval stage at concentrations as low as 50μg/mL, with an IC value (the concentration required to inhibit growth by 50%) of 12.6μg/mL.
• In addition to inhibiting development, procyanidin A2 significantly hindered the migration of larvae at concentrations of 25μg/mL.

Conclusion

• The researchers concluded that procyanidin A2 is the main anthelmintic compound in A. oleifolius. This discovery reaffirms the potential of using the plant in future programs for controlling cyathostomin infections in horses, especially in light of increasing resistance to existing anthelmintic treatments among these parasites.