Flavonoids are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in diets.
Polyphenols are a large family of naturally occurring organic compounds characterized by multiples of phenol units. They are abundant in plants and structurally diverse. Polyphenols include flavonoids, tannic acid, and ellagitannin, some of which have been used historically as dyes and for tanning garments.
Catechin is a flavan-3-ol, a type of natural phenol and antioxidant. It is a plant secondary metabolite. It belongs to the group of flavan-3-ols, part of the chemical family of flavonoids.
Proanthocyanidins are a class of polyphenols found in a variety of plants such as blueberry. Chemically, they are oligomeric flavonoids. Many are oligomers of catechin and epicatechin and their gallic acid esters. More complex polyphenols, having the same polymeric building block, form the group of tannins.
Thearubigins are polymeric polyphenols that are formed during the enzymatic oxidation and condensation of two gallocatechins with the participation of polyphenol oxidases during the fermentation reactions in black tea. Thearubigins are red in colour and are responsible for much of the staining effect of tea. Therefore, a black tea often appears red while a green or white tea has a much clearer appearance. The colour of a black tea, however, is affected by many other factors as well, such as the amount of theaflavins, another oxidized form of polyphenols.
Procyanidins are members of the proanthocyanidin class of flavonoids. They are oligomeric compounds, formed from catechin and epicatechin molecules. They yield cyanidin when depolymerized under oxidative conditions.
Vanillic acid is a dihydroxybenzoic acid derivative used as a flavoring agent. It is an oxidized form of vanillin. It is also an intermediate in the production of vanillin from ferulic acid.
The Duquenois reagent is used in the Rapid Modified Duquenois–Levine test, is an established screening test for the presence of cannabis. The test was initially developed in the 1930s by the French Medical Biochemist, Pierre Duquénois (1904–1986), and was adopted in the 1950s by the United Nations as the preferred test for cannabis, and originally claimed to be specific to cannabis. After several modifications, it became known as the Duquenois–Levine test. However, in the 1960s and 70s various studies showed that the test was not specific to cannabis. In 1973 the Supreme Court of Wisconsin ruled the D–L test insufficient evidence for demonstrating that a substance was cannabis, specifically noting that the D–L tests used "are not exclusive or specific for marijuana."
The phenolic content in wine refers to the phenolic compounds—natural phenol and polyphenols—in wine, which include a large group of several hundred chemical compounds that affect the taste, color and mouthfeel of wine. These compounds include phenolic acids, stilbenoids, flavonols, dihydroflavonols, anthocyanins, flavanol monomers (catechins) and flavanol polymers (proanthocyanidins). This large group of natural phenols can be broadly separated into two categories, flavonoids and non-flavonoids. Flavonoids include the anthocyanins and tannins which contribute to the color and mouthfeel of the wine. The non-flavonoids include the stilbenoids such as resveratrol and phenolic acids such as benzoic, caffeic and cinnamic acids.
Ehrlich's reagent or Ehrlich reagent is a reagent that contains p-dimethylaminobenzaldehyde (DMAB) and thus can act as an indicator to presumptively identify indoles and urobilinogen. Several Ehrlich tests use the reagent in a medical test; some are drug tests and others contribute to diagnosis of various diseases or adverse drug reactions. A very common Ehrlich test is a simple spot test to identify possible psychoactive compounds such as tryptamines and ergoloids. It gives a negative test-result for 25I-NBOMe and many other non-indole-related psychoactives. The reagent will also give a positive result for opium, because of the presence of tryptophan in natural opium. It is named after Nobel Prize winner Paul Ehrlich who used it to distinguish typhoid from simple diarrhoea.
Prodelphinidin is a name for the polymeric tannins composed of gallocatechin. It yields delphinidin during depolymerisation under oxidative conditions.
Leucocyanidin is a colorless chemical compound that is a member of the class of natural products known as leucoanthocyanidins.
A type proanthocyanidins are a specific type of proanthocyanidins, which are a class of flavonoid. Proanthocyanidins fall under a wide range of names in the nutritional and scientific vernacular, including oligomeric proanthocyanidins, flavonoids, polyphenols, condensed tannins, and OPCs. Proanthocyanidins were first popularized by French scientist Jacques Masquelier.
Procyanidin A2 is an A type proanthocyanidin.
Epicatechin gallate (ECG) is a flavan-3-ol, a type of flavonoid, present in green tea. It is also reported in buckwheat and in grape.
Condensed tannins are polymers formed by the condensation of flavans. They do not contain sugar residues.
Tryptophol is an aromatic alcohol that induces sleep in humans. It is found in wine as a secondary product of ethanol fermentation. It was first described by Felix Ehrlich in 1912. It is also produced by the trypanosomal parasite in sleeping sickness.
Dragendorff's reagent is a color reagent to detect alkaloids in a test sample or as a stain for chromatography plates. Alkaloids, if present in the solution of sample, will react with Dragendorff's reagent and produce an orange or orange-red precipitate. This reagent was invented by the German pharmacologist, Johann Georg Dragendorff (1836–1898) at the University of Dorpat.
