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

Abstract

Caffeine (CA) 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 CA and its metabolites may serve as reliable diagnostic markers for early Parkinson's disease (PD) patients. In this study, we demonstrated a new MEKC method for determining CA and its three main downstream metabolites, paraxanthine (PX), theobromine (TB), and theophylline (TP), in human plasma. Plasma samples were collected, and analyzed using MEKC, after SPE. 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 CA, 5.0 ng/mL for TB, and 4.0 ng/mL for both PX and TP. The recoveries were between 88.0% and 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 PD than in control subjects (p < 0.05). The area under curve was improved to 0.839 when CA and its three main metabolites were included, suggesting that MEKC testing of CA, TP, TB, and PX may serve as a potential method for early diagnosis of PD.

Strategies for capillary electrophoresis: Method development and validation for pharmaceutical and biological applications—Updated and completely revised edition

“…Here, the optimum BGE was composed of 50 mM sodium phosphate, pH 9 and 30 mM SDS; allowing the analysis of ethanol, butanol, and pentanol with limit of detections (LODs) of 0.17%, 0.18%, and 0.50%, respectively [51]. Table 2 [28,42,44,45,49,[52][53][54][55][56][57][58][59] provides additional examples of combinations of BGEs optimized for the separation of specific analytes.…”

“…The BGE were 1 × TBE containing SDS (10-35 mM) and PEO (5.0 × 10 −6 -5.0 × 10 −5 g/mL) [54] Synthetic cathinones 75 mM borate buffer at pH 9.3 and 0.4 mM of C12E10 surfactant [55] Caffeine and its main metabolites 35 mM phosphate, pH of 10.5, and 25 mM SDS [56] Apolipoproteins on human VLDL 3). Additional examples are listed in Table 5 and Table 6.…”

Exploring Partial Structural Disorder in Anhydrous Paraxanthine through Combined Experiment, Solid-State Computational Modelling, and Molecular Docking

“…Molecular mechanism of PX action is determined by its potent but nonselective antagonism to adenosine A1, A2A, and A2B receptors, which are involved in such processes as regulation of myocardial, oxygen consumption, and coronary blood flow, as well as in neurotransmitters, such as dopamine and glutamate, and in inflammation and immune responses [12]. Thus, it affects fundamental human processes, such as sleep, arousal, cognition, learning, and memory, and can stimulate the central nervous system, as well as the muscular, respiratory and circularity systems [4,[13][14][15][16][17][18][19]. PX treatment may affect short-term memory, reasoning, response time to cognitive challenges, and help to sustain attention [19].…”

“…PX, unlike CF, is a potent dopaminergic and protects against neurodegeneration and loss of synaptic function [20]. PX, rather than CF, has recently been reported to reduce the risk of developing Alzheimer's and Parkinson's diseases [4,15,21,22]. It was approved by the FDA for the treatment of most reversible obstructive airway diseases (e.g., chronic bronchitis, emphysema, and asthma), but later relegated from the treatment of chronic obstructive pulmonary disease (COPD) due to an imbalance between benefits and side effects [16].…”

Simultaneous quantitation of serum caffeine and its metabolites by ultra‐high‐performance liquid chromatography–tandem mass spectrometry for CYP1A2 activity prediction in premature infants

“…Unfortunately, both failed to quantify these four analytes simultaneously using 100 μL plasma because of the low sensitivity of the HPLC method. Several quantitative methods for determination of CA and its different metabolites in plasma, urine and saliva in adult volunteers have been reported, for example, HPLC, micellar electrokinetic capillary chromatography and MS (Begas et al, 2015; Caubet et al, 2002; Dobson et al, 2016; Han et al, 2020; Jordan et al, 2015; Ptolemy et al, 2010; Turjap et al, 2016). An HPLC–tandem mass spectrometry (MS/MS) method has been reported to quantify CA, PX, TP and TB simultaneously in human plasma with the linear range of CA from 4.1 to 3000 ng/mL (Chen et al, 2017).…”