Simultaneous quantification of glutathione, glutathione disulfide and glutathione-S-sulfonate in grape and wine using LC-MS/MS

A robust ultra-performance liquid chromatography-tandem mass spectrometry method for simultaneous determination of 10 components in glutathione cycle

Glutathione (GSH) is an important antioxidant that is generated and degraded via the GSH cycle. Quantification of the main components in the GSH cycle is necessary to evaluate the process of GSH. In this study, a robust ultra-performance liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of 10 components (GSH; γ-glutamylcysteine; cysteinyl-glycine; n-acetylcysteine; homocysteine; cysteine; cystine; methionine; glutamate; pyroglutamic acid) in GSH cycle was developed. The approach was optimized in terms of derivative, chromatographic, and spectrometric conditions as well as sample preparation. The unstable thiol groups of GSH, γ-glutamylcysteine, cysteinyl-glycine, n-acetylcysteine, cysteine, and homocysteine were derivatized by n-ethylmaleimide. The derivatized and underivatized analytes were separated on an amino column with gradient elution. The method was further validated in terms of selectivity (no interference), linearity (R2 > 0.99), precision (% relative standard deviation [RSD%] range from 0.57 to 10.33), accuracy (% relative error [RE%] range from -3.42 to 10.92), stability (RSD% < 5.68, RE% range from -2.54 to 4.40), recovery (RSD% range from 1.87 to 7.87) and matrix effect (RSD% < 5.42). The validated method was applied to compare the components in the GSH cycle between normal and oxidative stress cells, which would be helpful in clarifying the effect of oxidative stress on the GSH cycle.

Optimization of extraction and development of an LC-HRMS method to quantify glutathione and glutathione disulfide in white wine lees and yeast derivatives

The antioxidant capacity of wine depends on its quality and aging potential. Aging on lees can improve this capacity thanks to the release of glutathione (GSH), as can the addition of yeast derivatives (YD). Therefore, the GSH potential of wine lees (WL) and YD requires investigation. We propose an optimized method to extract and quantify GSH from WL and YD. First, a method was developed to detect and quantify GSH and glutathione disulfide (GSSG) using LC-HRMS. Second, Box-Behnken response surface methodologies (RSM) were applied to both matrices. Results showed that the main parameter affecting GSH extraction efficiency was ethanol concentration. Quantitation of various samples revealed GSH concentrations of up to 900 µg/g for WL and 40 mg/g for YD. To our knowledge, the absolute quantitation of GSH/GSSG in these matrices has not been reported until now.

Ultrahighly Sensitive and Selective Glutathione Sensor Based on Carbon Dot-Functionalized Solution-Gate Graphene Transistor

A new type of carbon dot (CD)-functionalized solution-gated graphene transistor (SGGT) sensor was designed and fabricated for the highly sensitive and highly selective detection of glutathione (GSH). The CDs were synthesized via a one-step hydrothermal method using DL-thioctic acid and triethylenetetramine (TETA) as sources of S, N, and C. The CDs have abundant amino and carboxyl groups and were used to modify the surface of the gate electrode of SGGT as probes for detecting GSH. Remarkably, the CDs-SGGT sensor exhibited excellent selectivity and ultrahigh sensitivity to GSH, with an ultralow limit of detection (LOD) of up to 10-19 M. To the best of our knowledge, the sensor outperforms previously reported systems. Moreover, the CDs-SGGT sensor shows rapid detection and good stability. More importantly, the detection of GSH in artificial serum samples was successfully demonstrated.

Beyond the Bottle: Exploring Health-Promoting Compounds in Wine and Wine-Related Products-Extraction, Detection, Quantification, Aroma Properties, and Terroir Effects

Health-promoting compounds in wine and wine-related products are important due to their potential benefits to human health. Through an extensive literature review, this study explores the presence of these compounds in wine and wine-related products, examining their relationship with terroir and their impact on the aromatic and flavor properties that are perceived orally: sunlight exposure, rainfall patterns, and soil composition impact grapevines' synthesis and accumulation of health-promoting compounds. Enzymes, pH, and the oral microbiome are crucial in sensory evaluation and perception of health promotion. Moreover, their analysis of health-promoting compounds in wine and wine-related products relies on considerations such as the specific target compound, selectivity, sensitivity, and the complexity of the matrix.

Voltammetric studies of glutathione transfer across arrays of liquid-liquid microinterfaces for sensing applications

The simple and facilitated transfer of tripeptide glutathione across the water/2-nitrophenyl octhyl ether interface was studied via cyclic voltammetry at interface between two immiscible electrolyte solutions (ITIES). The micro-perforated membrane prepared with a laser with a femtosecond pulse was used for mechanical stabilization of the interface. The method of cyclic voltammetry was used to study the passive and facilitated interfacial transfer of glutathione and its complex with the crown ether dibenzo-18-crown-6 (DB18C6).The glutathione mass transfer mechanism was established and substantiated, the diffusion coefficients, thermodynamic characteristics of interphase transfer and the constant of complexation of the glutathione by DB18C6 were determined. Square wave voltammetry based on facilitated transfer was used for more accurate and sensitive determination of glutathione low detection limit (0.8 μM) with wide linear dynamic range (from 3.0 to 80 μM) was reached. The influence of various potentially interfering ions on the voltammetric determination of glutathione has also been investigated. The method developed was applied to determine glutathione in aqueous solutions and malt extract.