Analysis of iridoids from Harpagophytum and eleutherosides from Eleutherococcus senticosus in horse urine.

The study investigates how Liquid Chromatography/Mass Spectroscopy can identify the consumption of two plants, Harpagophytum and Eleutherococcus senticosus, in horses. Main evidence was the presence of specific compounds (harpagoside and eleutheroside E respectively) in the horses’ urine. However, detection rates differed greatly, with harpagophytum evidence found in only one out of 317 urine samples tested, versus eleutheroside E detected in almost 39% of 382 samples.

Methodology and Findings

• The study utilised Liquid Chromatography/Electron Spray Ionization-Mass Spectroscopy (LC/ESI-MS n) techniques. These methods were previously developed for the detection of Harpagophytum and preparations containing Eleutherococcus senticosus, both plants possessing health benefits for horses.
• The analysis focused on identifying specific compounds as primary evidence of the plants’ consumption. Harpagoside was identified as the main indicator of Harpagophytum ingestion, whilst Eleutheroside E provided evidence of Eleutherococcus senticosus consumption.
• Rapid analysis of a large number of urine samples from horses of various origins was conducted to verify the efficacy of these methods in real-life scenarios.

Key Findings

• Examination of 317 samples for the intake of Harpagophytum returned only one positive detection. The positive sample revealed the presence of harpagoside, harpagide, and 8-para-coumaroyl harpagide; these compounds occur in conjunction in this plant.
• On the contrary, the investigation into Eleutherococcus senticosus consumption presented different results:
  • Post-administration samples from two horses that had received a feed supplement containing Eleutherococcus senticosus for several days exhibited traces of eleutheroside E – the primary indicator of the plant’s consumption.
  • Additionally, out of the total 382 samples tested, 39% returned positive results for the presence of eleutheroside E. This surprisingly high detection rate was independent of sample origin and could not be attributed solely to the use of herbal dietary supplements.

Conclusions and Implications

• The study reaffirms the effectiveness of LC/ESI-MS n methods in detecting specific plant consumptions in horses through urinalysis.
• The low detection rate of Harpagophytum might suggest that it is either not commonly consumed or that it doesn’t stay in the horse’s system for long.
• The high detection rate of Eleutherococcus senticosus might indicate that it is more widely used, has a longer retention in the body, or could be inherent to the animal’s diet or environment in general, beyond intentional supplementation.
• Overall, the research findings present valuable insights for future research, particularly related to equine diet and management, as well as for the development and refinement of drug testing methodologies in sport and veterinary science.