Everything below concerns Analytical method. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-04-08. Numbers and descriptions here follow the published literature rather than marketing material.
Glutathione serves as a cofactor for several enzymes, including glutathione peroxidase and glutathione S-transferase. These enzymes help reduce hydrogen peroxide and lipid peroxides, and they conjugate reactive electrophiles for excretion. The molecule also acts as a reservoir for cysteine, an amino acid that is prone to oxidation. In addition, glutathione participates in the metabolism of nitric oxide, leukotrienes, and prostaglandins. Its roles extend to cell signaling, apoptosis, and the regulation of protein function through S-glutathionylation.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine, and it is the most abundant non-protein thiol in most living cells. The reduced form, GSH, carries a sulfhydryl group that can donate electrons, while the oxidized form, GSSG, forms when two GSH molecules link via a disulfide bond. The balance between these two forms helps define the cellular redox environment, and their ratio is often used as an indicator of oxidative stress. Because the sulfhydryl group is reactive, glutathione participates in many cellular processes, including detoxification and protein regulation.
Biosynthesis proceeds in two ATP-dependent steps. First, glutamate-cysteine ligase joins glutamate and cysteine. Second, glutathione synthetase adds glycine to the intermediate. The pathway is regulated by cysteine availability, enzyme expression, and feedback inhibition by glutathione itself. Liver tissue has a particularly high capacity for synthesis and export. Because the molecule is made inside cells, circulating glutathione reflects a balance of release, uptake, and breakdown rather than simple dietary supply.
Functionally, glutathione supports redox balance by donating electrons and becoming oxidized. It also serves as a cofactor for enzymes such as glutathione peroxidases and glutathione S-transferases. These enzymes participate in peroxide reduction and in conjugation reactions that help process reactive molecules. Separate from antioxidant roles, glutathione can modify protein cysteines through S-glutathionylation, influencing enzyme activity and signaling. Research continues to examine how these chemical roles translate into whole-organism effects.
| Property | Value | Notes |
|---|---|---|
| Chemical formula | C10H17N3O6S | Reduced form (GSH) |
| Molar mass | 307.32 g/mol | For GSH; GSSG is 612.63 g/mol |
| Appearance | White crystalline powder | Usually lyophilized |
| Solubility in water | Freely soluble (≥100 mg/mL) | pH dependent |
| Typical storage | -20 °C, desiccated | Protect from light and oxygen |
Measuring glutathione requires attention to sample preparation because the molecule oxidizes readily. Blood, tissue, and cell samples are often treated with acid to precipitate proteins and stabilize the thiol. Without such steps, GSH can convert to GSSG or form mixed disulfides during storage. Analytical methods include spectrophotometric assays, high-performance liquid chromatography, and mass spectrometry. Each approach has different sensitivity, specificity, and susceptibility to interference from related compounds in complex matrices.
For solid glutathione, storage conditions affect shelf life. The reduced form is typically kept cool, dry, and protected from air and light. Moisture can promote oxidation, while elevated temperatures accelerate degradation. Suppliers often specify storage at or below freezing, sometimes under inert gas. Solutions are less stable than powders and may require preparation shortly before use. Buffers and chelating agents can slow oxidation, but they do not eliminate it. Published stability data vary with matrix, pH, and container.
Cells synthesize glutathione through two ATP-dependent enzymatic steps. The first step combines glutamate and cysteine to form gamma-glutamylcysteine, catalyzed by glutamate-cysteine ligase. The second step adds glycine, producing the complete tripeptide, catalyzed by glutathione synthetase. Glutathione itself can inhibit the first enzyme, providing negative feedback when levels are high. Because cysteine is often limiting, its availability influences how quickly the pathway proceeds. These reactions occur in the cytosol, and the resulting glutathione can be distributed to other compartments.
Glutathione functions in redox balance, detoxification, and sulfur amino acid storage. It participates in reactions that help maintain ascorbate and protein thiol status. The molecule serves as a cofactor for several enzymes, including glutathione peroxidases and glutathione S-transferases. These enzymes reduce peroxides and conjugate electrophiles, respectively. Glutathione also contributes to the metabolism of xenobiotics and to the transport of cysteine between tissues. How interorgan transport and tissue-specific regulation shape whole-body pools remains an active area of study.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine. Its cysteine residue carries a thiol group, which allows the molecule to participate in reduction and oxidation reactions. The compound exists in most living cells, where the reduced form, often abbreviated GSH, is usually more abundant than the oxidized disulfide form, GSSG. Intracellular concentrations are commonly in the millimolar range, while extracellular concentrations are much lower. This uneven distribution supports its role as a major cellular redox buffer.
Quality control for glutathione materials checks identity, assay, purity, water content, and disulfide content. Commercial products vary from research-grade powder to dietary supplements, and labels may not distinguish reduced from oxidized forms. In the United States, oral glutathione is commonly sold as a dietary supplement rather than an approved drug, while injectable forms fall under different rules and may require a prescription. Regulatory status differs by country. Analytical certificates, when available, help verify what a material contains, but independent testing remains important for interpretation.
Laboratory measurement of glutathione typically starts with rapid acid extraction to prevent oxidation and enzymatic degradation. Common methods include enzymatic recycling assays, high-performance liquid chromatography, and liquid chromatography coupled with mass spectrometry. The recycling assay uses glutathione reductase and a thiol-reactive colorimetric or fluorescent reagent, measuring total glutathione after converting disulfide forms. Chromatographic methods can separate reduced and oxidized forms, which helps when the redox ratio is the target. Choice of method affects sensitivity, specificity, and the amount of sample needed.
Samples for glutathione analysis require careful handling because the compound oxidizes readily and can be consumed by enzymes after collection. Blood is often treated with acid or thiol-blocking agents soon after draw, and plasma should be separated quickly from red blood cells. Tissues are usually snap-frozen or extracted immediately. Aqueous solutions of glutathione are less stable than dry powder and degrade faster at neutral or alkaline pH, in light, or with dissolved oxygen. Repeated freeze-thaw cycles also reduce reliability.
In cells, glutathione helps maintain the reducing environment of the cytosol and supports enzymes that counteract reactive oxygen species. It acts as a cofactor for glutathione peroxidases, which reduce hydrogen peroxide and lipid peroxides, and for glutathione S-transferases, which conjugate electrophiles. The ratio of GSH to GSSG is often used as an indicator of oxidative stress, although the ratio can vary by compartment and cell type. Glutathione also stores cysteine, an amino acid that can be limiting for protein synthesis and antioxidant defense.
Synthesis occurs in two ATP-dependent steps. The enzyme glutamate-cysteine ligase joins glutamate and cysteine to form gamma-glutamylcysteine, and glutathione synthetase adds glycine. The first step is rate-limiting and is influenced by cysteine availability and feedback inhibition by GSH. Breakdown involves gamma-glutamyl transferase and subsequent peptidases, which release constituent amino acids for reuse. Because turnover differs among tissues, measurements from blood, plasma, and tissues are not directly interchangeable. Research continues to clarify how compartment-specific pools are regulated in health and disease.
==== Hospitalized patients ==== Remdesivir was approved for medical use in the United States in October 2020. The US Food and Drug Administration (FDA) approved remdesivir based on the agency's analysis of data from three randomized, controlled clinical trials that included participants hospitalized with mild-to-severe COVID‑19. The FDA granted approval and reissued the revised EUA to Gilead Sciences Inc. The FDA approved remdesivir based primarily on evidence from three clinical trials (NCT04280705, NCT04292899, and NCT04292730) of 2043 hospitalized participants with COVID‑19. The trials were conducted at 226 sites in 17 countries including the United States. In November 2020, the World Health Organization (WHO) updated its guideline on therapeutics for COVID‑19 to include a conditional recommendation against the use of remdesivir, triggered by results from the WHO Solidarity trial. Meanwhile, the Public Health Agency of Canada's COVID‑19 Clinical Pharmacology Task Group recommended that remdesivir only be administered to hospitalized patients as part of a randomized controlled trial due to limited information on risks and benefits. In January 2022, the Canadian component of the WHO Solidarity Trial reported that in-hospital people with COVID‑19 treated with remdesivir had 17% lower relative risk of death (18.7% versus 22.6% death rates) and 47% reduced relative risk for needing oxygen and mechanical ventilation (8.0% versus 15.0%) compared to people receiving standard-of-care treatments.
== Production == One method for industrial production of dried cherries involves first dipping them in a boiling 0.5–2% solution of sodium carbonate (NaCO3) for up to 20 seconds, and then rinsing in cool water; this induces small cracks in the skin and speeds up the drying process. Some other possible materials for the dipping solution include ethyl oleate and oleyl alcohol; adding alkalis like potassium carbonate (K2CO3) to such a dip was shown to have no positive effect on drying time. Such results had already been demonstrated in scientific research by the 1940s. Dried cherries might also be produced by freeze drying or air drying. After drying, they typically have a moisture content of around 25%. Adding sulfur dioxide (SO2) may help to improve color and flavour retention over long periods of storage. Sweet varieties recommended for drying include Lambert, Royal Ann, Napoleon, Van, or Bing; tart varieties recommended for drying include Early Richmond or Large Montmorency. Most cherries sold in North America are sour varieties (either Montmorency or Morello). The first recorded experiments attempting to dry Montmorency tart cherries were performed in the late 1970s by professors at Utah State University. After drying the cherries, they were rolled in sugar and then sampled as "snow cherries".
The Miller–Urey experiment, or Miller experiment, was an experiment in chemical synthesis carried out in 1952 that simulated the conditions thought at the time to be present in the atmosphere of the early, prebiotic Earth. It is seen as one of the first successful experiments demonstrating the synthesis of organic compounds from inorganic constituents in an origin of life scenario. The experiment used methane (CH4), ammonia (NH3), hydrogen (H2), in ratio 2:2:1, and water (H2O). Applying an electric arc (simulating lightning) resulted in the production of amino acids. It is regarded as a groundbreaking experiment, and the classic experiment investigating the origin of life (abiogenesis). It was performed in 1952 by Stanley Miller, supervised by Nobel laureate Harold Urey at the University of Chicago, and published the following year. At the time, it supported Alexander Oparin's and J. B. S. Haldane's hypothesis that the conditions on the primitive Earth favored chemical reactions that synthesized complex organic compounds from simpler inorganic precursors. After Miller's death in 2007, scientists examining sealed vials preserved from the original experiments showed that more amino acids were produced in the original experiment than Miller reported with paper chromatography. While evidence suggests that Earth's prebiotic atmosphere might have typically had a composition different from the gas used in the Miller experiment, prebiotic experiments continue to produce racemic mixtures of simple-to-complex organic compounds, including amino acids, under varying conditions.
Saffron likely originated in Iran, Greece, Mesopotamia, or Kashmir. Harold McGee states that it was domesticated in or near Greece during the Bronze Age. C. sativus is probably a triploid form of Crocus cartwrightianus, which is also known as "wild saffron". Saffron crocus was slowly propagated by humans throughout much of Eurasia and was later brought to parts of North Africa, North America, and Oceania. Several wild species of Crocus similar to the commercial plant are known to have been harvested in recent times for use as saffron. Crocus ancyrensis was used to make saffron in Sivas in Central Turkey, the corms were also eaten. Crocus cartwrightianus was harvested on Andros in the islands of the Cyclades, for medicinal purposes and the stigmas for making a pigment called Zafran. Crocus longiflorus stigmas were used for saffron in Sicily. Crocus thomasii stigmas were used to flavour dishes around Taranto, South Italy. In Syria the stigmas of an unknown wild species were collected by women and children, sun-dried and pressed into small tablets which were sold in the Bazaars. Not all ancient depictions or descriptions of saffron spice or flowers are certain to be the same species as the modern commercial species used for spice.
Sources: en.wikipedia.org
==== Cancer ==== The mechanism of action of arsenic trioxide anti-cancer effects is complex and not fully understood. Generally, the drug inhibits the proliferation of cancer cells and induces their differentiation and/or apoptosis, which can occur in various ways depending on the involved organelles and biochemical processes. Arsenic trioxide induces apoptosis through:
In the following years, the Swedish Navy added another seven submarines in three different classes (Undervattensbåten No 2, Laxen, and Abborren class) using the same propulsion technology but fitted with true diesel engines rather than semidiesels from the outset. Since by that time, the technology was usually based on the diesel engine rather than some other type of combustion engine, it eventually came to be known as diesel–electric transmission. Like many other early submarines, those initially designed in Sweden were quite small (less than 200 tonnes) and thus confined to littoral operation. When the Swedish Navy wanted to add larger vessels, capable of operating further from the shore, their designs were purchased from companies abroad that already had the required experience: first Italian (Fiat-Laurenti) and later German (A.G. Weser and IvS). As a side-effect, the diesel–electric transmission was temporarily abandoned. However, diesel–electric transmission was immediately reintroduced when Sweden began designing its own submarines again in the mid-1930s. From that point onwards, it has been consistently used for all new classes of Swedish submarines, albeit supplemented by air-independent propulsion (AIP) as provided by Stirling engines beginning with HMS Näcken in 1988.
Aliphatic, Semi-aromatic (also referred to as alipharomatic), Aromatic: these are the most used polyimides because of their thermostability. According to the type of interactions between the main chains, polyimides can be:
Sources: en.wikipedia.org
Glutathione is a tripeptide of three amino acids: glutamate, cysteine, and glycine. The cysteine residue provides the sulfhydryl group that gives the molecule its reducing properties.
GSH is the reduced form, which contains a free sulfhydryl group. GSSG is the oxidized form, formed when two GSH molecules join through a disulfide bond. The ratio of GSH to GSSG is often used to assess cellular redox status.
No, glutathione is synthesized endogenously in most cells. It is not classified as an essential nutrient because the body can produce it from amino acid precursors. Dietary sources exist, but they are not required to maintain life.
Glutathione is a sulfur-containing tripeptide made from glutamate, cysteine, and glycine. It is found in most cells and participates in redox balance and detoxification reactions.