Forskning

June 10, 2020

Detection of caffeine and its main metabolites for early diagnosis of Parkinson’s disease using micellar electrokinetic capillary chromatography

Y Han et al, 2020. Detection of caffeine and its main metabolites for early diagnosis of Parkinson’s disease using micellar electrokinetic capillary chromatography, Electrophoresis, published online.

ABSTRACT:

Caffeine is a common xanthine alkaloid found in tea leaves, coffee beans, and other natural plants, and is the most widely used psychotropic substance in the world. Accumulating evidence suggests that low plasma levels of caffeine and its metabolites may serve as reliable diagnostic markers for early Parkinson’s disease patients. In this study, we demonstrated a new MEKC method for determining caffeine and its three main downstream metabolites, paraxanthine, theobromine and theophylline, in human plasma. Plasma samples were collected and analyzed after solid-phase extraction, by using MEKC. The running buffer was composed of 35 mM phosphate, pH of 10.5, and 25 mM SDS. The separation voltage was 15 kV and the detection wavelength was at 210 nm. Under the optimum conditions, four distinct analytes were completely separated and detected in less than 12 min. Method limits of detection were as low as 7.5 ng/mL for caffeine, 5.0 ng/mL for theobromine and 4.0 ng/mL for both paraxanthine and theophylline. The recoveries were between 88.0%-105.9%. This method was successfully applied to 27 human plasma samples. The results indicate that the plasma concentrations of the four analytes are significantly lower in patients with early Parkinson’s disease than in control subjects (p<0.05). The area under curve was improved to 0.839 when caffeine and its three main metabolites were included, suggesting that MEKC testing of caffeine, theophylline, theobromine, and paraxanthine may serve as a potential method for early diagnosis of Parkinson’s disease.