Norbadione A is a

pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compou ...

found in the

bay bolete ''Imleria badia'', common name, commonly known as the bay bolete, is an edible mushroom, edible, pored mushroom found in Eurasia and North America, where it grows in Temperate coniferous forest, coniferous or mixed woods on the ground or on ...

mushroom (''Boletus badius''). A

polyphenol 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 o ...

, norbadione A is related to a family of

mushroom A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans. The standard for the name "mushroom" is ...

pigments known as

pulvinic acid Pulvinic acids are natural chemical pigments found in some lichens, derived biosynthetically from the aromatic amino acids phenylalanine and tyrosine, via dimerization and oxidative ring-cleavage of aryl pyruvic acids, a process that also produ ...

s. The molecule has also been reported as a

potassium salt In chemistry, a salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a compound with no net electric charge. A common example is table salt, with positively ch ...

from the mushrooms '' Pisolithus tinctorius'' (horse dung fungus) and ''

Chalciporus piperatus ''Chalciporus piperatus'', commonly known as the peppery bolete, is a small pored mushroom of the family Boletaceae found in mixed woodland in Europe and North America. It has been recorded under introduced trees in Brazil, and has become n ...

''.

Properties

Norbadione A has seven acid-base

functional group In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the re ...

s, among which are two

enol In organic chemistry, alkenols (shortened to enols) are a type of reactive structure or intermediate in organic chemistry that is represented as an alkene ( olefin) with a hydroxyl group attached to one end of the alkene double bond (). The t ...

ic and two carboxylic acid moieties. These functional groups confer water-solubility to the molecule. It selectively complexes

cesium Caesium (IUPAC spelling) (or cesium in American English) is a chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of , which makes it one of only five elemental metals that ar ...

cations (Cs⁺), with an efficiency comparable to that of some

calixarene A calixarene is a macrocycle or cyclic oligomer based on a methylene-linked phenols. With hydrophobic cavities that can hold smaller molecules or ions, calixarenes belong to the class of cavitands known in host–guest chemistry. Nomenclature Cal ...

s or

crown ether In organic chemistry, crown ethers are cyclic chemical compounds that consist of a ring containing several ether groups (). The most common crown ethers are cyclic oligomers of ethylene oxide, the repeating unit being ethyleneoxy, i.e., . Impo ...

s. It has been investigated for its ability to provide a protective effect against the damaging effects of ionizing radiation, an effect attributed to its ability to protect DNA-related targets from irradiation. Tests with cell cultures and mice show that although it has some protective effect, it is

toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subs ...

to cells in higher doses. A diverse array of synthetic derivatives of norbadione A has been created to explore the effect of structure on antioxidant properties and cytotoxicity. A series of alkali chelators based on the structure of norbadione A has been reported. The intramolecular

protonation In chemistry, protonation (or hydronation) is the adding of a proton (or hydron, or hydrogen cation), (H+) to an atom, molecule, or ion, forming a conjugate acid. (The complementary process, when a proton is removed from a Brønsted–Lowry acid ...

process has been determined. There is a pH-dependent ''Z'' to ''E'' isomer switch that occurs in both pulvinate moieties, which yields four stereoisomeric forms (''E/E'', ''E/Z'', ''Z/Z'', ''Z/E''). These stereoisomers may have a widely differing ability to form complexes with Cs⁺ in solution.

Synthesis

Bourdreux and colleagues reported a

total synthesis Total synthesis is the complete chemical synthesis of a complex molecule, often a natural product, from simple, commercially-available precursors. It usually refers to a process not involving the aid of biological processes, which distinguishes i ...

of norbadione A in 2008. The technique uses a

regioselective In chemistry, regioselectivity is the preference of chemical bonding or breaking in one direction over all other possible directions. It can often apply to which of many possible positions a reagent will affect, such as which proton a strong Base ( ...

Diels–Alder reaction and a double Suzuki-Miyaura cross-coupling.

References

{{Reflist, colwidth=30em, refs= {{cite journal , vauthors=Aumann DC, Clooth G, Steffan B, Steglich W , title=Complexation of cesium-137 by the cap pigments of the bay boletus (''Xerocomus badius'') , journal=Angewandte Chemie International Edition in English , year=1989 , volume=28 , issue=4 , pages=453–454 , doi=10.1002/anie.198904531 {{cite journal , vauthors=Bourdreux Y, Nowaczyk S, Billaud C, Mallinger A, Willis C, Murr MD, Toupet L, Lion C, Gall TL, Mioskowski C , title=Total synthesis of norbadione A , journal=Journal of Organic Chemistry , year=2008 , volume=73 , issue=1 , pages=22–26 , pmid=18052074 , doi=10.1021/jo702106u {{cite journal , vauthors=Habrant D, Poigny S, Ségur-Derai M, Brunel Y, Heurtaux B, Le Gall T, Strehle A, Saladin R, Meunier S, Mioskowski C, Wagner A , title=Evaluation of antioxidant properties of monoaromatic derivatives of pulvinic acids , journal=Journal of Medicinal Chemistry , year=2009 , volume=52 , issue=8 , pages=2454–2464 , doi=10.1021/jm801500h , pmid=19309153 {{cite journal , vauthors=Korovitch A, Mulon JB, Souchon V, Leray I, Valeur B, Mallinger A, Nadal B, Le Gall T, Lion C, Ha-Duong NT, El Hage Chahine JM , title=Norbadione A: kinetics and thermodynamics of cesium uptake in aqueous and alcoholic media , journal=Journal of Physical Chemistry B , year=2010 , volume=114 , issue=39 , doi=10.1021/jp1060232 , pmid=20831226 , pages=12655–12665 {{cite journal , vauthors=Korovitch A, Le Roux A, Barbault F, Hémadi M, ((Ha-Duong N-T)), Lion C, Wagner A, ((El Hage Chahine J-M)) , title=A new series of Cs⁺, K⁺ and Na⁺ chelators: Synthesis, kinetics, thermodynamics and modeling , journal=Inorganica Chimica Acta , year=2013 , volume=394 , pages=45–57 , doi=10.1016/j.ica.2012.08.009 {{cite journal , vauthors=Kuad P, Borkovec M, Desage-El Murr M, Le Gall T, Mioskowski C, Spiess B , title=Inframolecular protonation process of norbadione A: Influence of the ionic environment and stereochemical consequences , journal=Journal of the American Chemical Society , year=2005 , volume=127 , issue=4 , pages=1323–1333 , doi=10.1021/ja0483185 , pmid=15669874 {{cite journal , vauthors=Kuad P, Schurhammer R, Maechling C, Antheaume C, Mioskowski C, Wipff G, Spiess B , title=Complexation of Cs+, K+ and Na+ by norbadione A triggered by the release of a strong hydrogen bond: nature and stability of the complexes , journal=Physical Chemistry Chemical Physics , year=2009 , volume=11 , issue=44 , pages=10299–10310 , doi=10.1039/b912518c , pmid=19890513, bibcode=2009PCCP...1110299K {{cite journal , vauthors=Le Roux A, Josset E, Benzina S, Nadal B, Desage-El Murr M, Heurtaux B, Taran F, ((Denis J-M)), Le Gall T, Meunier S, Bischoff P , title=Evaluation of the radioprotective potential of the polyphenol norbadione A , journal=Letters in Drug Design & Discovery , year=2012 , volume=9 , issue=1 , pages=48–53 , doi=10.2174/157018012798192900 {{cite journal , vauthors=Schurhammer R, Diss R, Spiess B, Wipff G , title=Conformational and Cs⁺ complexation properties of norbadione-A: A molecular modeling study , journal=Physical Chemistry Chemical Physics , year=2007 , volume=10 , issue=4 , pages=495–505 , doi=10.1039/B712836C , pmid=18183312 , url=https://univoak.eu/islandora/object/islandora%3A88399 {{cite book , author=Thompson RH , title=Naturally Occurring Quinones IV , url=https://books.google.com/books?id=qkd61S3gDfMC&pg=PA282 , year=1997, publisher=Springer , isbn=978-0-7514-0248-3 , page=282 {{cite book , author=Yannai S. , title=Dictionary of Food Compounds , url=https://books.google.com/books?id=_pHQQQkl8FMC&pg=PA1416 , year=2013 , publisher=CRC Press , isbn=978-1-4200-8351-4 , page=1416 Biological pigments Hispidins