ABSTRACT
This study aimed to determine whether the eggs of laying hens fed caffeine contain this compound and its primary metabolites (theophylline, theobromine, and paraxanthine). Laying hens were distributed into four experimental groups fed rations containing 0 (control), 150, 300, or 450 µg/g of caffeine. For residual analysis, six eggs per group were collected after 4, 8, and 12 weeks. The concentrations of caffeine, theophylline, theobromine, and paraxanthine were determined in the white and yolk of each egg by a high-performance liquid chromatography with photodiode array detector (HPLC-PDA) method. All four compounds were detected in the white and yolk of eggs produced by hens fed caffeine, but their levels in the egg white were approximately twice those in the yolk. The major metabolite found in eggs was theophylline (57.5% of caffeine metabolites in the egg white and 58.5% in the yolk), followed by theobromine (39.9% in the egg white and 41.5% in the yolk), and paraxanthine (2.64% in the egg white and non-detected in the yolk). In summary, caffeine and its metabolites, theophylline, theobromine, and paraxanthine, are transferred to the chicken eggs.
ABSTRACT
Plumbago scandens L. (Plumbaginaceae) occurs in all regions of Brazil. It has been described as toxic to cattle and goats. Caustic lesions in the upper digestive tract characterize poisoning. P. scandens contains a naphthoquinone named plumbagin, which presents high cytotoxic activity. Plumbago auriculata Lam., a widely used ornamental plant, is considered potentially toxic, but there is limited data about its toxicity. This work aimed to validate analytical methodologies for determining the levels of plumbagin in samples of leaves, stems, and rumen content to be used as an auxiliary chemical marker in the laboratory diagnosis of intoxication. One methodology used thin layer chromatography (TLC), and another used high-performance liquid chromatography (HPLC). The presence of palisade grass (Urochloa brizantha (Hochst. ex A.Rich.) R.D.Webster), Guinea grass (Megathyrsus maximus (Jacq.) B.K.Simon & S.W.L.Jacobs), corn silage, and rumen content did not interfere with plumbagin in the two methodologies. The TLC methodology generates qualitative results but is simple to implement and has a low cost. The HPLC methodology showed a limit of detection (LOD) of 0.01 µg/mL and a limit of quantification (LOQ) of 0.05 µg/mL. Leaf and stem samples of P. scandens evaluated showed high levels of plumbagin (0.261 ± 0.087 % and 0.327 ± 0.055 %, respectively). In contrast, leaves of P. auriculata did not show detectable levels of the toxin, and some stem samples showed low levels (up to 0.000114 %). Thus, these methodologies can be used to confirm or rule out the consumption of P. scandens in rumen content from animals suspected of poisoning.
