Stilbenoids are

hydroxylated In chemistry, hydroxylation can refer to: *(i) most commonly, hydroxylation describes a chemistry, chemical process that introduces a hydroxyl group () into an organic compound. *(ii) the ''degree of hydroxylation'' refers to the number of OH gr ...

derivatives of

stilbene Stilbene may refer to one of the two stereoisomers of 1,2-diphenylethene: * (''E'')-Stilbene (''trans'' isomer) * (''Z'')-Stilbene (''cis'' isomer) See also * Stilbenoids, a class of molecules found in plants * 1,1-Diphenylethylene 1,1-Diphenyl ...

. They have a C₆–C₂–C₆ structure. In biochemical terms, they belong to the family of

phenylpropanoid The phenylpropanoids are a diverse family of organic compounds that are synthesized by plants from the amino acids phenylalanine and tyrosine. Their name is derived from the six-carbon, aromatic phenyl group and the three-carbon propene tail of ...

s and share most of their

biosynthesis Biosynthesis is a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms. In biosynthesis, simple compounds are modified, converted into other compounds, or joined to form macromolecules. ...

pathway with

chalcones Chalconoids Greek: χαλκός ''khalkós'', "copper", due to its color), also known as ''chalcones'', are natural phenols related to chalcone. They form the central core for a variety of important biological compounds. They show antibacterial, a ...

. Most stilbenoids are produced by plants, and the only known exception is the antihelminthic and antimicrobial stilbenoid, 2-isopropyl-5- ''E'')-2-phenylvinylenzene-1,3-diol, biosynthesized by the Gram-negative bacterium ''

Photorhabdus luminescens ''Photorhabdus luminescens'' (previously called ''Xenorhabdus luminescens'') is a Gammaproteobacterium of the family Morganellaceae, and is a lethal pathogen of insects. It lives in the gut of an entomopathogenic nematode of the family Heteror ...

.''

Chemistry

Stilbenoids are

derivatives of

and have a C₆–C₂–C₆ structure. They belong to the family of

s and share most of their

pathway with

. Under UV irradiation, stilbene and its derivatives undergo intramolecular cyclization, called

stilbene photocyclization In organic chemistry, the Mallory reaction is a photochemical-cyclization– elimination reaction of diaryl-ethylene structures to form phenanthrenes and other polycyclic form polycyclic aromatic hydrocarbons and heteroaromatics.Mallory, F. B.; Mall ...

to form

dihydrophenanthrene Phenanthrenoids are chemical compounds formed with a phenanthrene backbone. These compounds occur naturally in plants, although they can also be synthesized. Phenanthrols Phenanthrols are any of five isomeric phenols derived from phenanthrene ( ...

s. Oligomeric forms are known as

oligostilbenoid Oligostilbenoids (oligo- or polystilbenes) are oligomeric forms of stilbenoids. Some molecules are large enough to be considered polyphenols and constitute a class of tannins. Examples Dimers * Ampelopsin A * Epsilon-viniferin * Pallidol * ...

Types

;Aglycones *

Piceatannol Piceatannol is the organic compound with the formula . Classified as a stilbenoid and a phenol, it is a white solid, although samples often are yellow owing to impurities. Natural occurrences Piceatannol and its glucoside, astringin, are found i ...

in the roots of Norway spruces *

Pinosylvin Pinosylvin is an organic compound with the formula C6H5CH=CHC6H3(OH)2. A white solid, it is related to trans-stilbene, but with two hydroxy groups on one of the phenyl substituents. It is very soluble in many organic solvents, such as acetone. O ...

is a fungal toxin protecting wood from fungal infection, found in trees of the pine family *

Pterostilbene Pterostilbene () (trans-3,5-dimethoxy-4-hydroxystilbene) is a stilbenoid chemically related to resveratrol. In plants, it serves a defensive phytoalexin role. Natural occurrence Pterostilbene is found in almonds, various ''Vaccinium'' berries ( ...

in almonds, pine and

vaccinium ''Vaccinium'' is a common and widespread genus of shrubs or dwarf shrubs in the heath family (Ericaceae). The fruits of many species are eaten by humans and some are of commercial importance, including the cranberry, blueberry, bilberry (whort ...

berries *

Resveratrol Resveratrol (3,5,4′-trihydroxy-''trans''-stilbene) is a stilbenoid, a type of natural phenol, and a phytoalexin produced by several plants in response to injury or when the plant is under attack by pathogens, such as bacteria or fungi. Sources ...

in grapes ;Glycosides *

Astringin Astringin is a stilbenoid, the 3-β-D-glucoside of piceatannol. It can be found in the bark of ''Picea sitchensis'' or ''Picea abies'' (Norway spruce). It is also present in ''Vitis vinifera'' cells cultures and in wine. See also *Phenolic co ...

in the bark of Norway spruce *

Piceid Piceid is a stilbenoid glucoside and is a major resveratrol derivative in grape juices. It can be found in the bark of ''Picea sitchensis''. It can also be isolated from ''Reynoutria japonica'' ( syn. ''Fallopia japonica''), the Japanese knotweed ...

is a resveratrol derivative in grape juices

Production

Stilbenoids are produced in various plants, for example they are secondary products of

heartwood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin tha ...

formation in trees that can act as

phytoalexins Phytoalexins are antimicrobial substances, some of which are antioxidative as well. They are defined, not by their having any particular chemical structure or character, but by the fact that they are defensively synthesized ''de novo'' by plants t ...

. Another example is

resveratrol Resveratrol (3,5,4′-trihydroxy-''trans''-stilbene) is a stilbenoid, a type of natural phenol, and a phytoalexin produced by several plants in response to injury or when the plant is under attack by pathogens, such as bacteria or fungi. Sources ...

, an antifungal which is found in

grape A grape is a fruit, botanically a berry, of the deciduous woody vines of the flowering plant genus ''Vitis''. Grapes are a non- climacteric type of fruit, generally occurring in clusters. The cultivation of grapes began perhaps 8,000 years ago, ...

s and which has been suggested to have health benefits.

Ampelopsin A Ampelopsin A is a resveratrol dimer found in ''Ampelopsis glandulosa ''Ampelopsis glandulosa'' is a species of plant native to China, Japan, India, Nepal, Myanmar, Vietnam, and the Philippines. Varieties Several varieties are distinguished: ...

and

Ampelopsin B Ampelopsin B is a stilbenoid dimer found in ''Ampelopsis glandulosa ''Ampelopsis glandulosa'' is a species of plant native to China, Japan, India, Nepal, Myanmar, Vietnam, and the Philippines. Varieties Several varieties are distinguished: ...

are resveratrol dimers produced in porcelain berry. A bacterial stilbenoid, (''E'')-3,5-dihydroxy-4-isopropyl-''trans''-stilbene, is produced by ''

Photorhabdus ''Photorhabdus'' is a genus of bioluminescent, gram-negative bacilli which lives symbiotically within entomopathogenic nematodes, hence the name ''photo'' (which means light producing) and ''rhabdus'' (rod shape). ''Photorhabdus'' is known to be ...

'' which is a bacterial symbiont of insect nematodes called ''

Heterorhabditis ''Heterorhabditis'' is a genus of nematodes belonging to the order Rhabditida. All species of this genus are obligate parasites of insects, and some are used as biological control agents for the control of pest insects. ''Heterorhabditis'' nemato ...

''. Stilbenoids are

secondary metabolite Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animals, or plants, which are not directly involved in the norm ...

s present in

Cannabis sativa ''Cannabis sativa'' is an annual Herbaceous plant, herbaceous flowering plant indigenous to East Asia, Eastern Asia, but now of cosmopolitan distribution due to widespread cultivation. It has been cultivated throughout recorded history, used as ...

Properties

Phytoalexins have been suggested by some studies to be responsible for resistance to some tree diseases, such as

pine wilt ''Bursaphelenchus xylophilus'', commonly known as pine wood nematode or pine wilt nematode (PWN), is a species of nematode that infects trees in the ''Pinus'' genus of coniferous trees and causes the disease pine wilt.Combretastatin Combretastatin is a dihydrostilbenoid found in '' Combretum caffrum''. As a class Combretastatins are a class of natural phenols. A variety of different natural combretastatin molecules are present in the bark of '' Combretum caffrum'', commonly ...

s, many are stilbenoids *

Dihydrostilbenoid Dihydrostilbenoids (bibenzyls) are natural phenols formed from the dihydrostilbene ( bibenzyl) backbone. Examples Dihydro-resveratrol is a natural phenol with a bibenzyl structure found in wine. It is also a metabolite of trans-resveratrol forme ...

s, no double bond on the bridge *

List of antioxidants in food This is a list of antioxidants naturally occurring in food. Vitamin C and vitamin E – which are ubiquitous among raw plant foods – are confirmed as dietary antioxidants, whereas vitamin A becomes an antioxidant following metabolism of p ...

List of phytochemicals in food While there is ample evidence to indicate the health benefits of diets rich in fruits, vegetables, legumes, whole grains and nuts, no specific food has been acknowledged by scientists and government regulatory authorities as providing a health bene ...

Phytochemistry Phytochemistry is the study of phytochemicals, which are chemicals derived from plants. Phytochemists strive to describe the structures of the large number of secondary metabolites found in plants, the functions of these compounds in human and ...

Secondary metabolites Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animals, or plants, which are not directly involved in the nor ...

Stilbestrol Stilbestrol, or stilboestrol, also known as 4,4'-dihydroxystilbene or 4,4'-stilbenediol, is a stilbenoid nonsteroidal estrogen and the parent compound of a group of more potent nonsteroidal estrogen derivatives that includes, most notably, dieth ...

References

Books

* * {{Phenylpropanoids