Quinones as novel chemiluminescent probes for the sensitive and selective determination of biothiols in biological fluids

Abstract

Altered plasma aminothiol concentrations are thought to be a valuable risk indicator and are interestingly utilized for routine clinical diagnosis and for the monitoring of various metabolic disorders and human diseases, and accordingly there is a need for an accurate and reliable assay capable of simultaneously determining aminothiols including glutathione (GSH), N-acetylcysteine (NAC), homocysteine (Hcys), and cysteine (Cys) in human plasma. Herein, a highly sensitive, selective, and very fast HPLC-chemiluminescence (HPLC-CL) coupled method is reported, exploiting for the first time the strong nucleophilicity and high reactivity of aminothiols toward quinones for a CL assay. The unique redox-cycling capability of quinone and/or Michael addition adducts, thioether-quinone conjugates, was utilized to establish a novel analytical method based on the reaction of adducts with dithiothreitol (DTT) to liberate reactive oxygen species (ROS), which are detected by using a luminol-CL assay. Specimen preparation involved the derivatization of aminothiols with menadione (MQ) for 5 minutes at room temperature. A unique green chemistry synthesis of thioether-quinones in HEPES buffer (pH 8.5) was introduced by using our reaction methodology without needing any hazardous organic solvent or catalyst. The aminothiol-MQ adducts were separated using solid-phase extraction followed by isocratic elution on an ODS column. Linearity was observed in the range of 2.5-500, 5-500, 10-1500, and 20-2000 nM with detection limits (S/N of 3) of 3.8, 4.2, 8, and 16 (fmol per injection) for GSH, NAC, Hcys, and Cys, respectively. The method was successfully applied for the selective determination of aminothiols in human plasma from healthy people and patients with rheumatic arthritis and diabetes mellitus. The obtained results postulated the usefulness of our method for investigating the relationship between aminothiol metabolism and related human disorders.

Interactive Materials for Bidirectional Redox‐Based Communication

“…The difference spectrum between the Cat Ox and Cat Red film shows a peak near 420 nm, which is consistent with the characteristic peak of thiol‐quinone adduct. [ 29 ] In summary, electrodeposition by catechol (but not by AS) leads to conjugation and crosslinking with redox‐active catecholic moieties.…”

A novel and simple imidazo[1,2-a]pyridin fluorescent probe for the sensitive and selective imaging of cysteine in living cells and zebrafish

“…Cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) are three biological thiols present in organisms [1][2][3][4]. Their metabolism and transport are closely related to the functional expression of many significant enzymes and proteins in the body [5]. Abnormal levels of biothiols in vivo can cause and indicate various diseases.…”

Determination of Anthraquinone-Tagged Amines Using High-Performance Liquid Chromatography with Online UV Irradiation and Luminol Chemiluminescence Detection

“…It was possible to determine quinone by measuring the CL produced through the above reactions. As an application to HPLC analysis, we reported a determination method of aminothiols in biological samples using menadione as a pre-column derivatization reagent [20,21]. The Michael addition reaction between menadione and aminothiol yielded a menadione-tagged aminothiol, which retained the ROS-generating capability of the parent menadione.…”