biomarker

4-Hydroxynonenal (4-HNE) (4-HNE) is an oxidative nitrosative stress biomarker. It is a substrate and an inhibitor of acetaldehyde dehydrogenase 2 (ALDH2).

7α-Hydroxycholesterol, a cholesterol oxide formed through both enzymatic and non-enzymatic oxidation, can serve as a biomarker for lipid peroxidation.

1,3,7-Trimethyluric acid, a purine alkaloid, occurs as a minor metabolite of caffeine in humans. It functions as an antioxidant with the ability to scavenge hydroxyl radicals and offers protective benefits against lipid peroxidation in erythrocyte membranes.

Lathosterol, a molecule akin to cholesterol, serves as a biomarker for the body's total cholesterol synthesis, as indicated by its serum concentration.

Formiminoglutamic acid (NSC 334078) is a biomarker for formylaminoglutaminuria, an indicator of folate deficiency.

3,5-Dihydroxybenzoic acid is a metabolite of alkylresorcinols in human urine and plasma, a potential biomarker of food intake such as beer, nuts, peanuts, and legumes, and a selective hydroxycarboxylic acid 1 (HCA1) inhibitor.

1-Hydroxypyrene (1-Pyrenol), a biomarker of exposure to polycyclic aromatic hydrocarbons, is analyzed in urine samples.

Indole-3-methanamine has been detected, but not quantified in, barley, cereals, and cereal products.

Methionine sulfoxide, an oxidation product of methionine formed through interaction with reactive oxygen species, serves as a biomarker for oxidative stress in vivo.

N-Methylsarcosine (Dimethylglycine) is used as an athletic performance enhancer and immunostimulant. It is also used in the treatment of autism, epilepsy and mitochondrial disease. It is also employed as a biomarker of protein degradation in chronic obstructive lung disease (COPD) patients. Further, it is used as a substrate to identify, differentiate and characterize amino acid methyltransferase. It plays an important role in the development of glycine-based ionic liquids and emulsifiers.

2-Hydroxybutyric acid (α-Hydroxybutyric acid) is a product of protein metabolism and serves as a biomarker for type 2 diabetes and pre-eclampsia.

D-(+)-Xylose (Wood sugar) is an aldopentose - a monosaccharide containing five carbon atoms and an aldehyde functional group. It has chemical formula C5H10O5 and is 40% as sweet as sucrose. Xylose is also found in mucopolysaccharides of connective tissue and sometimes in the urine. Xylose is the first sugar added to serine or threonine residues during proteoglycan type O-glycosylation. Therefore xylose is involved in the biosythetic pathways of most anionic polysaccharides such as heparan sulphate and chondroitin sulphate. In medicine, xylose is used to test for malabsorption by administering a xylose solution to the patient after fasting. If xylose is detected in the blood and or urine within the next few hours, it has been absorbed by the intestines. Xylose is said to be one of eight sugars which are essential for human nutrition, the others being galactose, glucose, mannose, N-acetylglucosamine, N-acetylgalactosamine, fucose, and sialic acid. . Xylose in the urine is a biomarker for the consumption of apples and other fruits.

Trans-Aconitic acid is normally present in normal human urine, and it has been suggested that is present in larger amounts with Reye's syndrome and organic aciduria. trans-Aconitic acid is a substrate of enzyme trans-aconitate 2-methyltransferase (EC 2.1.

L-Arabinitol (L-(-)-Arabitol) is a potential biomarker for the comsuption of the food products such as sweet potato, deerberry, moth bean. L-Arabinitol is associated with Alzheimer's disease and ribose-5-phosphate isomerase deficiency.

5'-Guanylic acid disodium salt (GMP-5) is a purine ribonucleoside monophosphate. L-Glutamic acid and guanosine monophosphate are biosynthesized from xanthylic acid and L-glutamine via GMP synthase [glutamine-hydrolyzing]. Guanosine triphosphate and guanosine monophosphate are biosynthesized from diguanosine tetraphosphate via bis(5'-nucleosyl)-tetraphosphatase [asymmetrical]. In humans, guanosine monophosphate is involved in the kanamycin, telithromycin, tobramycin, and erythromycin action pathways, and several metabolic disorders including AICA-ribosiduria, adenosine deaminase deficiency, adenine phosphoribosyltransferase deficiency (aprt), and 2-hydroxyglutric aciduria (D and L form) pathways. Guanosine monophosphate is also found in foods like onion-family vegetables, millet, Chinese water chestnut, and red rice, serving as a potential biomarker for the consumption of these foods.

D-(-)-Tartaric acid (D-Tartaric acid; (S, S)-tartarate; D-threaric acid) is mainly located in the cytoplasm. D-(-)-Tartaric acid can be converted into (2S,3S)-cis-fertaric acid and (2S,3S)-trans-fertaric acid. Outside the human body, it can be found in vinegar. This makes it a potential biomarker for the consumption of this food.

2-Hydroxyphenylacetic acid (Ortho-Hydroxyphenylacetic acid) can be found in a number of food items such as natal plum, lemon verbena, half-highbush blueberry, and parsley, which makes 2-Hydroxyphenylacetic acid a potential biomarker for the consumption of these food products. 2-Hydroxyphenylacetic acid (Ortho-Hydroxyphenylacetic acid) can be found primarily in blood, feces, and urine.

1,3,5-Trimethoxybenzene (Phloroglucinol trimethyl ether) is a methoxybenzene carrying methoxy groups at positions 1, 3 and 5. It has been found to be a biomarker of flavonoid consumption in humans. It has a role as a biomarker and a human xenobiotic metabolite.

N-Acetyl-L-arginine (Ac-Arg-OH), an N-acyl-L-alpha-amino acid with a strong basic nature (based on its pKa), has elevated serum levels in hyperargininemic patients and is associated with several diseases, including uremia and colorectal cancer. In untreated hyperargininemic patients, it reaches its highest levels in cerebrospinal fluid. It has also been detected in apples and loquats, suggesting it could be a potential biomarker for consumption of these foods. Additionally, a low-arginine diet combined with sodium benzoate therapy leads to a marked decrease in plasma N-acetyl-L-arginine concentrations.

γ-Hexalactone (γ-caprolactone) belongs to the class of organic compounds known as gamma butyrolactones. Gamma butyrolactones are compounds containing a gamma butyrolactone moiety, which consists of an aliphatic five-member ring with four carbon atoms, one oxygen atom, and bears a ketone group on the carbon adjacent to the oxygen atom. Thus, Gamma-caprolactone is considered to be a fatty ester lipid molecule. Gamma-Caprolactone is a very hydrophobic molecule, practically insoluble (in water), and relatively neutral. Gamma-Caprolactone exists in all eukaryotes, ranging from yeast to humans. Outside of the human body, Gamma-caprolactone has been detected, but not quantified in, several different foods, such as potato, cereals and cereal products, pomes, alcoholic beverages, and fruits. This could make Gamma-caprolactone a potential biomarker for the consumption of these foods. 4-hydroxy-Hexanoic acid gamma-lactone is occasionally found as a volatile component of human urine. In some cases differences up to an order of magnitude are observed. 4-hydroxy-Hexanoic acid gamma-lactone has been found in the polar fraction of human blood. Biological fluids such as blood and urine have been shown to contain a large number of components, some of them volatiles (low boiling point) apparently present in all individuals, while others such are much more variable. Although some of these changes may have dietary origins, others seem to be characteristic of the individual.

1H-Indole-3-carboxaldehyde (3-Formylindole), also known as 3-formylindole or 3-indolealdehyde, belongs to the class of organic compounds known as indoles. Indoles are compounds containing an indole moiety, which consists of pyrrole ring fused to benzene to form 2,3-benzopyrrole. 1H-Indole-3-carboxaldehyde is an extremely weak basic (essentially neutral) compound (based on its pKa). Outside of the human body, 1H-Indole-3-carboxaldehyde has been detected, but not quantified in, several different foods, such as gram beans, brussel sprouts, cucumbers, cereals and cereal products, and white cabbages. This could make 1H-indole-3-carboxaldehyde a potential biomarker for the consumption of these foods. A heteroarenecarbaldehyde that is indole in which the hydrogen at position 3 has been replaced by a formyl group.

Quercitrin (3-rhamnosyl quercetin) is a plant-derived flavonoid compound, displays antioxidant and anti-inflammatory activities. Quercitrin can be found in a number of food items such as garden tomato (var. ), German camomile, endive, and kiwi, which makes quercitrin a potential biomarker for the consumption of these food products.

7α-Hydroxy-4-cholesten-3-one is an intermediate in bile acid synthesis from cholesterol, a PXR agonist, and a biomarker for bile acid loss and diseases related to defective bile acid biosynthesis. It is also the physiological substrate for [CYP8B1].

Cinnamoylglycine, a glycine conjugate of cinnamic acid and a urinary metabolite in humans, is used as a potential urinary biomarker.