Flavonolignans are natural phenols composed of a part flavonoid and a part phenylpropane.
Flavonolignans identified in Silybum marianum (milk thistle) silymarin complex include silibinin, silychristin, silydianin, dehydrosilybin, deoxysilycistin, deoxysilydianin, silandrin, silybinome, silyhermin and neosilyhermin and can be produced in vitro. [1] Silibinin is found in the roots of S. marianum [2] while silyamandin [3] can be found in the fruit. [4]
Hydnocarpin can be found naturally in Onopordon corymbosum [5] and can be synthesised. [6]
Scutellaprostin A, B, C, D, E and F can be isolated from Scutellaria prostrata and can also be synthesized. [7]
Hydnowightin can be isolated from Hydnocarpus wightiana seeds. [8]
Three flavonolignans derived from the flavone tricin have been isolated from the herb Avena sativa . [9]
Palstatin has been isolated from the Amazon tree Hymeneae palustris . [10]
Salcolin A and salcolin B can be found in Salsola collina . [11]
Rhodiolin, the product of the oxidative coupling of coniferyl alcohol with the 7,8-dihydroxy grouping of the flavonol herbacetin, can be found in the rhizome of Rhodiola rosea . [12]
The flavonolignans tricin 4'-O-(erythro-beta-guaiacylglyceryl) ether and tricin 4'-O-(threo-beta-guaiacylglyceryl) ether can be isolated together with their 7-O-glucosides in the leaves of Hyparrhenia hirta. [13]
A 2022 research has concluded that flavonolignans "reduce the virulence of antibiotic-resistant bacterial strains". [14]
Rhodiola rosea is a perennial flowering plant in the family Crassulaceae. It grows naturally in wild Arctic regions of Europe, Asia, and North America, and can be propagated as a groundcover.
Silibinin (INN), also known as silybin (both from Silybum, the generic name of the plant from which it is extracted), is the major active constituent of silymarin, a standardized extract of the milk thistle seeds, containing a mixture of flavonolignans consisting of silibinin, isosilibinin, silychristin, silidianin, and others. Silibinin itself is a mixture of two diastereomers, silybin A and silybin B, in approximately equimolar ratio. The mixture exhibits a number of pharmacological effects, particularly in the fatty liver, non-alcoholic fatty liver, non-alcoholic steatohepatitis, and there is great clinical evidence for the use of silibinin as a supportive element in alcoholic and Child–Pugh grade 'A' liver cirrhosis. However, despite its several beneficial effects on the liver, silibinin and all the other compounds found in silymarin, especially silychristin seem to act as potent disruptors of the thyroid system by blocking the MCT8 transporter. The long term intake of silymarin can lead to some form of thyroid disease and if taken during pregnancy, silymarin can cause the development of the Allan–Herndon–Dudley syndrome. Although this information is not being taken into consideration by all regulatory bodies, several studies now consider silymarin and especially silychristin to be important inhibitors of the MCT8 transporter and a potential disruptor of the thyroid hormone functions.
Silybum marianum is a species of thistle. It has various common names including milk thistle, blessed milkthistle, Marian thistle, Mary thistle, Saint Mary's thistle, Mediterranean milk thistle, variegated thistle and Scotch thistle. This species is an annual or biennial plant of the family Asteraceae. This fairly typical thistle has red to purple flowers and shiny pale green leaves with white veins. Originally a native of Southern Europe through to Asia, it is now found throughout the world.
Phenanthrenoids are chemical compounds formed with a phenanthrene backbone. These compounds occur naturally in plants, although they can also be synthesized.
Tricin is a chemical compound. It is an O-methylated flavone, a type of flavonoid. It can be found in rice bran and sugarcane.
Dihydrokaempferide is a flavanonol, a type of flavonoid. It can be found in Prunus domestica, in the wood of Salix caprea and in the Brazilian green propolis.
Cynaroside is a flavone, a flavonoid-like chemical compound. It is a 7-O-glucoside of luteolin.
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.
Afzelechin is a flavan-3-ol, a type of flavonoid. It can be found in Bergenia ligulata. It exists as at least 2 major epimers.
Selliguea feei is a fern belonging to the genus Selliguea in the family Polypodiaceae. This fern can be collected in Indonesia. The species name feei commemorates the botanist Antoine Laurent Apollinaire Fée.
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.
Prenylated flavonoids or prenylflavonoids are a sub-class of flavonoids. They are widely distributed throughout the plant kingdom. Some are known to have phytoestrogenic or antioxidant properties. They are given in the list of adaptogens in herbalism. Chemically they have a prenyl group attached to their flavonoid backbone. It is usually assumed that the addition of hydrophobic prenyl groups facilitate attachment to cell membranes. Prenylation may increase the potential activity of its original flavonoid.
Herbacetin is a flavonol, a type of flavonoid.
Ombuin is an O-methylated flavonol, a type of flavonoid. It is the 4',7-O-methyl derivative of quercetin.
Patuletin is an O-methylated flavonol. It can be found in the genus Eriocaulon.
Axillarin is an O-methylated flavonol. It can be found in Pulicaria crispa, Filifolium sibiricum, Inula britannica, Wyethia bolanderi in Balsamorhiza macrophylla and in Tanacetum vulgare. It can also be synthesized.
δ-Viniferin is a resveratrol dehydrodimer. It is an isomer of epsilon-viniferin. It can be isolated from stressed grapevine leaves. It is also found in plant cell cultures and wine. It can also be found in Rheum maximowiczii.
Silychristin is a natural product and one of the constituents of silymarin, the standardized, active extract of the fruit of milk thistle, Silybum marianum. It is the second most abundant constituent in silymarin, after silybin. Silychristin is a flavonolignan, along with many other silymarin constituents, meaning it is composed up of a flavonoid and a lignan. It is estimated that up to 65–80% of silymarin extract is made up of flavonolignans, like silychristin, which give silymarin its well known potent antioxidant and hepatoprotective properties. Silychristin can exist as two stereoisomers, silychristin A and silychristin B. The marianum variety of S. marianum includes silychristin A as a major flavonolignan constituent, while the lesser known and studied albiflorum variety includes unique flavonolignans, including silyhermin, (–)-silandrin, and (+)-silymonin.
Cannabicitran (CBTC) is a phytocannabinoid first isolated in 1974 as a trace component of Cannabis sativa, Structurally related compounds can be found in some other plants. It is not psychoactive, but was found to reduce intraocular pressure in tests on rabbits, which may reflect agonist activity at the NAGly receptor that is known to be a target of many structurally related cannabinoids.