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Lactic acid is an organic acid. It is a chiral molecule, consisting of two optical isomers, L-lactic acid and D-lactic acid, with the L-isomer being the most common in living organisms. Lactic acid plays a role in several biochemical processes and is produced in the muscles during intense activity. In animals, L-lactate is constantly produced from pyruvate via the enzyme lactate dehydrogenase (LDH) in a process of fermentation during normal metabolism and exercise. It does not increase in concentration until the rate of lactate production exceeds the rate of lactate removal. This is governed by a number of factors, including monocarboxylate transporters, lactate concentration, the isoform of LDH, and oxidative capacity of tissues. The concentration of blood lactate is usually 1-2 mmol/L at rest, but can rise to over 20 mmol/L during intense exertion. There are some indications that lactate, and not glucose, is preferentially metabolized by neurons in the brain of several mammalian species, including mice, rats, and humans. Glial cells, using the lactate shuttle, are responsible for transforming glucose into lactate, and for providing lactate to the neurons. Lactate measurement in critically ill patients has been traditionally used to stratify patients with poor outcomes. However, plasma lactate levels are the result of a finely tuned interplay of factors that affect the balance between its production and its clearance. When the oxygen supply does not match its consumption, organisms adapt in many different ways, up to the point when energy failure occurs. Lactate, being part of the adaptive response, may then be used to assess the severity of the supply/demand imbalance. In such a scenario, the time to intervention becomes relevant: early and effective treatment may allow tissues and cells to revert to a normal state, as long as the oxygen machinery (i.e. mitochondria) is intact. Conversely, once the mitochondria are deranged, energy failure occurs even in the presence of normoxia. The lactate increase in critically ill patients may, therefore, be viewed as an early marker of a potentially reversible state (PMID: 16356243). When present in sufficiently high levels, lactic acid can act as an oncometabolite, an immunosuppressant, an acidogen, and a metabotoxin. An oncometabolite is a compound that promotes tumor growth and survival. An immunosuppressant reduces or arrests the activity of the immune system. An acidogen is an acidic compound that induces acidosis, which has multiple adverse effects on many organ systems. A metabotoxin is an endogenously produced metabolite that causes adverse health effects at chronically high levels. Chronically high levels of lactic acid are associated with at least a dozen inborn errors of metabolism, including 2-methyl-3-hydroxybutyryl CoA dehydrogenase deficiency, biotinidase deficiency, fructose-1,6-diphosphatase deficiency, glycogen storage disease type 1A (GSD1A) or Von Gierke disease, glycogenosis type IB, glycogenosis type IC, glycogenosis type VI, Hers disease, lactic acidemia, Leigh syndrome, methylmalonate semialdehyde dehydrogenase deficiency, pyruvate decarboxylase E1 component deficiency, pyruvate dehydrogenase complex deficiency, pyruvate dehydrogenase deficiency, and short chain acyl CoA dehydrogenase deficiency (SCAD deficiency). Locally high concentrations of lactic acid or lactate are found near many tumors due to the upregulation of lactate dehydrogenase (PMID: 15279558). Lactic acid produced by tumors through aerobic glycolysis acts as an immunosuppressant and tumor promoter (PMID: 23729358). Indeed, lactic acid has been found to be a key player or regulator in the development and malignant progression of a variety of cancers (PMID: 22084445). A number of studies have demonstrated that malignant transformation is associated with an increase in aerobic cellular lactate excretion. Lactate concentrations in various carcinomas (e.g. uterine cervix, head and neck, colorectal region) at first diagnosis of the disease, can be relatively low or extremely high (up to 40 µmol/g) in different individual tumors or within the same lesion (PMID: 15279558). High molar concentrations of lactate are correlated with a high incidence of distant metastasis. Low lactate tumors (< median of approximately 8 µmol/g) are associated with both an overall longer and disease-free survival compared to high lactate lesions (lactate > approximately 8 µmol/g). Lactate-induced secretion of hyaluronan by tumor-associated fibroblasts creates a milieu favourable for cell migration and metastases (PMID: 22084445). An acidic environment (pH 6-6.5), which is common in many tumors, allows tumor cells to evade the immune response, and therefore allows them to grow unchecked. Locally high concentrations of lactic acid are known to markedly impede the function of normal immune cells and will lead to a loss of T-cell function of human tumor-infiltrating lymphocytes (PMID: 22084445). Lactic acid is also an organic acid and acts as a general acidogen. Abnormally high levels of organic acids in the blood (organic acidemia), urine (organic aciduria), the brain, and other tissues lead to general metabolic acidosis. Acidosis typically occurs when arterial pH falls below 7.35. In infants with acidosis, the initial symptoms include poor feeding, vomiting, loss of appetite, weak muscle tone (hypotonia), and lack of energy (lethargy). These can progress to heart abnormalities, kidney abnormalities, liver damage, seizures, coma, and possibly death. These are also the characteristic symptoms of the untreated IEMs mentioned above. Many affected children with organic acidemias experience intellectual disability or delayed development. Lactic acid is also a microbial metabolite, urinary lactic acid is produced by Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Enterobacter, Acinetobacter, Proteus mirabilis, Citrobacter frundii, Enterococcus faecalis, Streptococcus group B, Staphylococcus saprophyticus (PMID: 22292465), Bacillus, Corynebacterium, Rhizopus and Saccharomyces cerevisiae (PMID: 26360870).

Lactic acid is an organic acid. It is a chiral molecule, consisting of two optical isomers, L-lactic acid and D-lactic acid, with the L-isomer being the most common in living organisms. Lactic acid plays a role in several biochemical processes and is produced in the muscles during intense activity. D-Lactic acid is the end product of the enzyme glyoxalase II (or hydroxyacyl-glutathione hydrolase) (EC 3.1.2.6), which converts the intermediate substrate S-lactoyl-glutathione to reduced glutathione and D-lactate (OMIM: 138790). Lactic acid is a microbial metabolite found in Aerococcus, Bacillus, Carnobacterium, Corynebacterium, Enterococcus, Escherichia, Lactobacillus, Lactococcus, Leuconostoc, Oenococcus, Pediococcus, Rhizopus, Saccharomyces, Streptococcus, Tetragenococcus, Vagococcus and Weissella (PMID:26287368; PMID:26360870).

3-Hydroxypropionic acid is a carboxylic acid. It is an intermediate in the breakdown of branched-chain amino acids and propionic acid from the gut. Typically it originates from propionyl-CoA and a defect in the enzyme propionyl carboxylase. This leads to a buildup in propionyl-CoA in the mitochondria.  Such a buildup can lead to a disruption of the esterified CoA:free CoA ratio and ultimately to mitochondrial toxicity. Detoxification of these metabolic end products occurs via the transfer of the propionyl moiety to carnitine-forming propionyl-carnitine, which is then transferred across the inner mitochondrial membrane. 3-Hydroxypropionic acid is then released as the free acid. As an industrial chemical, it is used in the production of various chemicals such as acrylates in industry. When present in sufficiently high levels, 3-hydroxypropionic acid can act as an acidogen and a metabotoxin. An acidogen is an acidic compound that induces acidosis, which has multiple adverse effects on many organ systems. A metabotoxin is an endogenously produced metabolite that causes adverse health effects at chronically high levels. Chronically high levels of hydroxypropionic acid are associated with many inborn errors of metabolism including biotinidase deficiency, malonic aciduria, methylmalonate semialdehyde dehydrogenase deficiency, methylmalonic aciduria, methylmalonic aciduria due to cobalamin-related disorders, and propionic acidemia. Hydroxypropionic acid is an organic acid. Abnormally high levels of organic acids in the blood (organic acidemia), urine (organic aciduria), the brain, and other tissues lead to general metabolic acidosis. Acidosis typically occurs when arterial pH falls below 7.35. Infants with acidosis have symptoms that include poor feeding, vomiting, loss of appetite, weak muscle tone (hypotonia), and lack of energy (lethargy). These can progress to heart, liver, and kidney abnormalities, seizures, coma, and possibly death. These are also the characteristic symptoms of the IEMs mentioned above. Many affected children with organic acidemias experience intellectual disability or delayed development. In adults, acidosis or acidemia is characterized by headaches, confusion, feeling tired, tremors, sleepiness, and seizures. 3-Hydroxypropionic acid is also a microbial metabolite found in Escherichia, Klebsiella and Saccharomyces (PMID: 26360870).

A 2-hydroxy monocarboxylic acid that is propanoic acid in which one of the alpha-hydrogens is replaced by a hydroxy group." []

Dimethyl carbonate is used for cold sterilisation of beverages. Effective against typical beverage-spoiling microorganisms, like yeasts and fermentative bacteria Dimethyl carbonate, often abbreviated DMC, is a flammable clear liquid boiling at 90 °C. It has recently found use as a methylating reagent. Its main benefit over other methylating reagents such as iodomethane and dimethyl sulfate is its lesser toxicity and its biodegradability. Also, it is now prepared from catalytic oxidative carbonylation of methanol with carbon monoxide and oxygen, instead of from phosgene making its production non-toxic and environmentally friendly. This allows dimethyl carbonate to be considered a green reagent

2-Acetamido-4-O-(1-carboxyethyl)-2-deoxyglucose is a natural product found in Proteus penneri with data available.

Glyceraldehyde is a triose monosaccharide with chemical formula C3H6O3. It is the simplest of all common aldoses. It is a sweet, colourless crystalline solid that is an intermediate compound in carbohydrate metabolism. The word "glyceraldehyde" comes from combining glycerine and aldehyde, as glyceraldehyde is merely glycerine with one hydroxide changed to an aldehyde. Glyceraldehyde is produced from the action of the enzyme glyceraldehyde dehydrogenase, which converts glycerol to glyceraldehyde using NADP as a cofactor. When present at sufficiently high levels, glyceraldehyde can be a cytotoxin and a mutagen. A cytotoxin is a compound that kills cells. A mutagen is a compound that causes mutations in DNA. Glyceraldehyde is a highly reactive compound that can modify and cross-link proteins. Glyceraldehyde-modified proteins appear to be cytotoxic, depress intracellular glutathione levels, and induce reactive oxygen species (ROS) production (PMID:14981296). Glyceraldehyde has been shown to cause chromosome damage to human cells in culture and is mutagenic in the Ames bacterial test.

A glycosylglucose formed by an alpha-(1->6)-linkage between D-galactose and D-glucose." []

Methoxyacetic acid belongs to the family of Carboxylic Acids. These are compounds containing a carboxylic acid group with the formula -C(=O)OH.

This compound belongs to the family of N-acyl-alpha-hexosamines. These are carbohydrate derivatives containing a hexose moeity in which the oxygen atom is replaced by an n-acyl group.

D-Maltose, also known as maltose, maltobiose or malt sugar, is a disaccharide formed from two units of glucose joined with an alpha (1→4) bond. Its name comes from malt, combined with the suffix '-ose' which is used in names of sugars. Maltose is a key structural motif of starch. When alpha-amylase breaks down starch, it removes two glucose units at a time, producing maltose. Maltose can be further broken down to glucose by the maltase enzyme, which catalyses the hydrolysis of the glycosidic bond. D-maltose exists in all living species, ranging from bacteria to plants to humans. Within humans, D-maltose participates in a number of enzymatic reactions. In particular, maltose can be converted into glucose; which is mediated by the enzyme maltase-glucoamylase. In addition, maltose can be converted into glucose through its interaction with the enzyme glycogen debranching enzyme. Maltose is found in high concentrations in oriental wheats and in a lower concentrations in sweet potato, grape wines, yellow pond-lilies, sunflowers, and spinach. Maltose is a component of malt, a substance which is obtained in the process of allowing grain to soften in water and germinate. It is also present in highly variable quantities in partially hydrolysed starch products like maltodextrin, corn syrup and acid-thinned starch. Maltose has a sweet taste but is only about 30–60% as sweet as sucrose, depending on the concentration.

A glycosylfructose that is D-fructofuranose attached to a alpha-D-glucopyranosyl unit at position 6 via a glycosidic linkage. It is found in honey and sugarcane." []

1,1-Dihydroxypropan-2-one is a natural product found in Homo sapiens, Catharanthus roseus, and other organisms with data available.

Pentaethylene glycol is a poly(ethylene glycol).

An aldohexose that is the C-3 epimer of glucose." []

A local anesthetic of the amide type now generally used for surface anesthesia. It is one of the most potent and toxic of the long-acting local anesthetics and its parenteral use is restricted to spinal anesthesia. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1006)

D-Arabitol is a polyol. Polyols are sugar alcohols linked to the pentose phosphate pathway (PPP). They are classified on the basis of the number of carbon atoms. Polyols occur in body fluids. A patient with leukoencephalopathy and peripheral neuropathy has been identified as suffering from ribose-5-phosphate isomerase (RPI) deficiency, a defect in the PPP. In this disorder, highly elevated concentrations of the C5 polyols such as D-arabitol are found in body fluids. In addition, transaldolase deficiency, another defect in the PPP, has been diagnosed in a patient with mainly liver problems among others. This patient had increased concentrations of polyols, mainly D-arabitol. So far, the pathophysiological role of polyols is relatively unknown. It is thought that D-arabitol is a metabolic end-product in humans. The strong brain-CSF-plasma gradient of polyols in the patient with RPI deficiency suggested a primary metabolic disorder. The mechanisms of brain and neuronal damage in RPI deficiency remain to be elucidated. A neurotoxic effect due to the accumulation of the polyols may play a role. D-Arabitol is a product of the enzyme D-arabinitol 4-dehydrogenase (EC 1.1.1.11) in the pentose and glucuronate interconversion pathway (PMID: 16435225, J Inherit Metab Dis. 2005;28(6):1181-3). D-Arabitol has also been found to be a fungal metabolite, urinary D-Arabinitol is a marker for invasive candidiasis or infection by Candida fungal species (PMID: 15183861; PMID: 10647119). It can also a metabolite in Debaryomyces, Pichia and Zygosaccharomyces (PMID: 25809659).

Oxalic acid is a strong dicarboxylic acid occurring in many plants and vegetables. It is produced in the body by metabolism of glyoxylic acid or ascorbic acid. It is not metabolized but excreted in the urine. It is used as an analytical reagent and general reducing agent (Pubchem). Oxalic acid (IUPAC name: ethanedioic acid, formula H2C2O4) is a dicarboxylic acid with structure (HOOC)-(COOH). Because of the joining of two carboxyl groups, this is one of the strongest organic acids. It is also a reducing agent. The anions of oxalic acid as well as its salts and esters are known as oxalates (Wikipedia). Bodily oxalic acid may also be synthesized via the metabolism of either glyoxylic acid or unused ascorbic acid (vitamin C), which is a serious health consideration for long term megadosers of vitamin C supplements. 80% of kidney stones are formed from calcium oxalate. Some Aspergillus species produce oxalic acid, which reacts with blood or tissue calcium to precipitate calcium oxalate. There is some preliminary evidence that the administration of probiotics can affect oxalic acid excretion rates (and presumably oxalic acid levels as well) (Wikipedia). Oxalic acid is found to be associated with fumarase deficiency and primary hyperoxaluria I, which are inborn errors of metabolism. Oxalic acid is a marker for yeast overgrowth from Aspergillus, Penicillum and/or Candida. Can also be elevated due to exposures from vitamin C or ethylene glycol poisoning. Oxalate is elevated in the urine of children with autism. (PMID: 21911305). Oxalic acid has also been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821).

The D-enantiomer of glyceraldehyde." []

The L-enantiomer of glyceraldehyde." []

Aldehydo-D-arabinose is an aldehydo-arabinose and a D-arabinose. It is an enantiomer of an aldehydo-L-arabinose. (2S,3R,4R)-2,3,4,5-tetrahydroxypentanal is a natural product found in Ascochyta medicaginicola, Codonopsis pilosula, and other organisms with data available. D-Arabinose is a metabolite found in or produced by Saccharomyces cerevisiae.

6Z-Octene-2,4-diynoic acid

6E-Octene-2,4-diynoic acid

Swertiamarin is a glycoside. Swertiamarin is a natural product found in Schultesia lisianthoides, Gentiana thunbergii, and other organisms with data available. See also: Centaurium erythraea whole (part of).