Yerba mate is a popular beverage in Argentina. It is a common practice to include used yerba mate in the horse’s feed.
The aim of this work is to study the different profiles of methylxanthines by LCMSMS and times to fall under the IRL, in urine samples after the administration of caffeine and the addition of yerba mate.
The trail was carried out on three male Thoroughbreds. From Day 1-3, 1 g of caffeine was administered daily (20mL i.v., Cardiotónico Cume ® Agropharma). From Day 10-15 they received 100 g of yerba mate along with the morning and afternoon meal (total of 10 doses). To simulate real conditions, yerba mate was pre-hydrated. Two horses received used yerba mate and one was given unused yerba mate. A total of 29 urine samples were taken within day 0 and 24.
The results showed that with Cume, the profile was Theophylline > Caffeine > Theobromine. However, after yerba mate intake, it shifted to Theobromine = Theophylline > Caffeine. The highest concentrations of all xanthines were found in the horse given unused yerba mate. Theobromine levels from yerba mate administration were notably higher than those from Cume.
The urinary concentration of theobromine fell below the IRL after two days with Cume, three days with used yerba mate, and four days with unused yerba mate. Theophylline and caffeine concentrations remained above the IRL for five days after the last administration of either Cume or yerba mate.
In conclusion, the profile of xanthines vary between the two treatments. Theobromine concentrations are below the IRL within two days after consuming Cume, and up to four days with unused yerba mate. In contrast, theophylline and caffeine remain above IRL for five days after the last administration of either Cume or yerba mate.