Chamaecydin is a chemical compound with the molecular formula C₃₀H₄₀O₃. It is made up of three six-membered rings and two five-membered rings and has one polar

hydroxyl In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydrox ...

functional group. It is well preserved in the rock record and is only found in a specific family of

conifers Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All ex ...

, the

swamp cypress Swamp cypress is a common name for more than one species of plants in the family Cupressaceae (cypresses): * Species of the genus ''Taxodium'' ** ''Taxodium distichum'', native to the Southeastern and Gulf Coastal Plains of the United States * '' G ...

subfamily. The presence and abundance of chamaecydin in the rock record can reveal environmental changes in ancient

biomes A biome () is a biogeographical unit consisting of a biological community that has formed in response to the physical environment in which they are found and a shared regional climate. Biomes may span more than one continent. Biome is a broader ...

Background

Notable properties

The molecule has a mass of 448.298 Daltons, and consists of two

carbonyl In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups. A compound containin ...

groups and three double bonds. It is a hexacarboxylic

triterpene Triterpenes are a class of chemical compounds composed of three terpene units with the molecular formula C30H48; they may also be thought of as consisting of six isoprene units. Animals, plants and fungi all produce triterpenes, including squal ...

. The 2d structure is shown in Figure 1. The physical properties are not well known; the

melting point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends ...

of chamaecydin is 197-198 C. Its

crystal structure In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions or molecules in a crystalline material. Ordered structures occur from the intrinsic nature of the constituent particles to form symmetric patterns t ...

orthorhombic In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with ...

. Chamaecydin shows significant

antifeedant Antifeedants are organic compounds produced by plants to inhibit attack by insects and grazing animals. These chemical compounds are typically classified as secondary metabolites in that they are not essential for the metabolism of the plant, but i ...

activity against the larvae of '' Spodoptera Iitura'' and has an antifeedant index (AFI) of 0.44. The index ranges from 1 to -1, with one being the most powerful antifeedant. It is calculated by comparing the amount of area lost in the treated disk to the amount of area lost in the control disk or C-T/C+T where C is control and T is treated.

Preservation

Chamaecydin is a

biomarker In biomedical contexts, a biomarker, or biological marker, is a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, p ...

for certain species of

Conifer Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All ex ...

trees. Once living organism die, the organic molecules they biosynthesized often undergo various chemical transformations in the soil and thus usually retain only basic structures of the molecules that were synthesized. These modified molecules are biomarkers but can often only be used as chemical tracers for a wide group of organisms. Chamaecydin is rare because it is a polar molecule that is found perfectly preserved millions of years later, and can therefore be used to trace specific species. Despite being a polar compound, chamaecydin is likely preserved because it is found trapped in

resin In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on n ...

ous plant material, where it is prevented from bonding to

kerogen Kerogen is solid, insoluble organic matter in sedimentary rocks. Comprising an estimated 1016 tons of carbon, it is the most abundant source of organic compounds on earth, exceeding the total organic content of living matter 10,000-fold. It ...

. In the paleorecord, it is found in clayey sediments, which prevents further oxidation. Chamaecydin is found in concentrations ranging 3–8.7 mg/g of organic carbon.

Biological sources

It was first isolated from the seed of ''

Chamaecyparis obtusa ''Chamaecyparis obtusa'' (Japanese cypress, hinoki cypress or hinoki; ja, 檜 or , ) is a species of cypress native to central Japan in East Asia, and widely cultivated in the temperate northern hemisphere for its high-quality timber and orna ...

'' (

Cupressaceae Cupressaceae is a conifer family, the cypress family, with worldwide distribution. The family includes 27–30 genera (17 monotypic), which include the junipers and redwoods, with about 130–140 species in total. They are monoecious, subdio ...

) and then from the leaves of ''

Cryptomeria ''Cryptomeria'' (literally "hidden parts") is a monotypic genus of conifer in the cypress family Cupressaceae, formerly belonging to the family Taxodiaceae. It includes only one species, ''Cryptomeria japonica'' (syn. ''Cupressus japonica'' ...

japonica'' D. Don. Chamaecydin has since been found to be unique to the swamp

cypress Cypress is a common name for various coniferous trees or shrubs of northern temperate regions that belong to the family Cupressaceae. The word ''cypress'' is derived from Old French ''cipres'', which was imported from Latin ''cypressus'', the la ...

subfamily (Taxodioideae), specifically, it has been most studied in these species: ''Cryptomeria japonica'', '' Glyptostrobus pensilis'', ''

Taxodium distichum ''Taxodium distichum'' (bald cypress, swamp cypress; french: cyprès chauve; ''cipre'' in Louisiana) is a deciduous conifer in the family Cupressaceae. It is native to the southeastern United States. Hardy and tough, this tree adapts to a wide r ...

'', and '' Taxodium mucronatum''. The molecule is found in the leaflets, seed cones, and wood of the cypress trees and can be traced back all the way to the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

period (~145.5 Ma). The other key

biomarkers In biomedical contexts, a biomarker, or biological marker, is a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, ...

for this sub family are ferruginol and 7α-p-cymenylferruginol. The synthesis methods of chamaecydin have not yet been studied.

Occurrence

s, deduced by the presence of chamaecydin in the paleorecord, managed to flourish across a wide range of latitudes over Earth's history. Below are some well studied occurrences of

conifer Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All ex ...

s. # The paleoflora of the Maritza-East basin was a marine environment that developed limnic conditions due to a

marine regression A marine regression is a geological process occurring when areas of submerged seafloor are exposed above the sea level. The opposite event, marine transgression, occurs when flooding from the sea covers previously-exposed land. Evidence of marin ...

. The area then experienced alternating dry and wet periods from intense precipitation during the

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but ...

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58lignite beds that formed in the dry periods, with one bed reaching 30 m in thickness. # Chamaecydin also confirms that large

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, a ...

forests were present north of the Arctic Circle (78 N) during the mid

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...

(45 Ma) at Axel Heiberg island. This is a unique habitat, which required them to be dormant during 3 months of winter darkness. The Arctic Circle at this time was very different from today: it was ice free and warm (12-17 degrees warmer than today) with lots of precipitation. These deposits occur in

fluvial In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluv ...

and

lacustrine A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...

settings. # The mid

(45 Ma) resinites from brown coal pits in northern

Germany Germany, officially the Federal Republic of Germany (FRG),, is a country in Central Europe. It is the most populous member state of the European Union. Germany lies between the Baltic and North Sea to the north and the Alps to the sou ...

contain chamaecydin and reveal a

semitropical swamp environment.{{Cite journal, last1=Simoneit, first1=Bernd R.T., last2=Otto, first2=Angelika, last3=Menor-Sálvan, first3=Cesar, last4=Oros, first4=Daniel R., last5=Wilde, first5=Volker, last6=Riegel, first6=Walter, date=February 2021, title=Composition of resinites from the Eocene Geiseltal brown coal basin, Saxony-Anhalt, Germany and comparison to their possible botanical analogues, url=http://dx.doi.org/10.1016/j.orggeochem.2020.104138, journal=Organic Geochemistry, volume=152, pages=104138, doi=10.1016/j.orggeochem.2020.104138, s2cid=228967077, issn=0146-6380

References

Triterpenes Biomarkers Tetracyclic compounds Spiro compounds Cyclopropanes Isopropyl compounds