3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||164.204 g·mol−1|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Thujaplicins (isopropyl cycloheptatrienolones) are a series of tropolone-related chemical substances that have been isolated from the hardwoods of the trees of Cupressaceae family.These compounds are known for their antibacterial, antifungal, and antioxidant properties. They were the first natural tropolones to be made synthetically.
Thujaplicins were discovered in the mid-1930s and purified from the heartwood of Thuja plicata Donn ex D. Don, commonly called as Western red cedar tree.These compounds were also identified in the constituents of Chamaecyparis obtusa , another species from the Cupressaceae family. C. obtusa is native to East Asian countries including Japan and Taiwan, and is also known as Taiwan hinoki, from which the β-thujaplicin was first isolated in 1936 and received its name, hinokitiol. Thujaplicins were the first natural tropolones to be made synthetically, by Ralph Raphael and colleagues, and the β-thujaplicin was the first non-benzenoid aromatic compound identified, by Tetsuo Nozoe and colleagues. The resistance of the heartwood of the tree to decay was the main reason prompting to investigate its content and identify the compounds responsible for antimicrobial properties. β-thujaplicin gained more scientific interest beginning in the 2000s. Later, iron-binding activity of β-thujaplicin was discovered and the molecule has been ironically nicknamed as “Iron Man molecule”, because the first name of Tetsuo Nozoe can be translated into English as “Iron Man”.
Tjujaplicins are found in the hardwoods of the trees belonging to the Cupressaceae family, including Chamaecyparis obtusa (Hinoki cypress), Thuja plicata (Western red cedar), Thujopsis dolabrata var. hondai (Hinoki asunaro), Juniperus cedrus (Canary Islands juniper), Cedrus atlantica (Atlas cedar), Cupressus lusitanica (Mexican white cedar), Chamaecyparis lawsoniana (Port Orford cedar), Chamaecyparis taiwanensis (Taiwan cypress), Chamaecyparis thyoides (Atlantic white cedar), Cupressus arizonica (Arizona cypress), Cupressus macnabiana (MacNab cypress), Cupressus macrocarpa (Monterey cypress), Juniperus chinensis (Chinese juniper), Juniperus communis (Common juniper), Juniperus californica (California juniper), Juniperus occidentalis (Western juniper), Juniperus oxycedrus (Cade), Juniperus sabina (Savin juniper), Calocedrus decurrens (California incense-cedar), Calocedrus formosana (Taiwan incense-cedar), Platycladus orientalis (Chinese thuja), Thuja occidentalis (Northern white-cedar), Thuja standishii (Japanese thuja), Tetraclinis articulata (Sandarac).
Thujaplicins can be produced in plant cell suspension cultures,or can be extracted from wood using solvents and ultrasonication.
Thujaplicins can be synthesized by cycloaddition of isopropylcyclopentadiene and dichloroketene, 1,3-dipolar cycloaddition of 5-isopropyl-1-methyl-3-oxidopyridinium, ring expansion of 2-isopropylcyclohexanone, regiocontrolled hydroxylation of oxyallyl (4+3) cycloadducts, from (R)-(+)-limonene regioselectively by several steps, and from troponeirontricarbonyl complex by few steps.
The synthesis pathway of β-thujaplicin by electro-reductive alkylation of substituted cycloheptatrienes is shown below:
The synthesis pathway of β-thujaplicin through ring expansion of 2-isopropylcyclohexanone is shown below:
The synthesis pathway of β-thujaplicin through oxyallyl cation [4+3] cyclization (Noyori's synthesis) is shown below:
Thujaplicins belong to tropolones containing an unsaturated seven-membered carbon ring. Thujaplicins are monoterpenoids that are cyclohepta-2,4,6-trien-1-one substituted by a hydroxy group at position 2 and an isopropyl group at positions 3, 4 or 5. mg/ml, respectively. β-thujaplicin provides acetone on vigorous oxidation and gives the saturated monocyclic diol upon catalytic hydrogenation. It is stable to alkali and acids, forming salts or remaining unchanged, but does not convert to catechol derivatives. The complexes made of iron and tropolones display high thermodynamic stability and has shown to have a stronger binding constant than the trnasferrin-iron complex.These compounds are enols and cyclic ketones. They derive from a hydride of a cyclohepta-1,3,5-triene. Thujaplicins are soluble in organic solvents and aqueous buffers. Hinokitiol is soluble in ethanol, dimethyl sulfoxide, dimethylformamide with a solubility of 20, 30 and 12.5
There are three naturally occurring monocyclic tropolones described: α-thujaplicin, β-thujaplicin (hinokitiol), and γ-thujaplicin.And the most common isomer occurring in the nature is β-thujaplicin.
|Compound||Chemical structure||3D model of the molecule||IUPAC name|
Thujaplicins are shown to act against Reticulitermes speratus (Japanese termites), Coptotermes formosanus (super termites), Dermatophagoides farinae (dust mites), Tyrophagus putrescentiae (mould mites), Callosobruchus chinensis (adzuki bean weevil), Lasioderma serricorne (cigarette beetle).
Hinokitiol has also shown some larvicidal activities against Aedes aegypti (yellow fever mosquito) and Culex pipiens (common house mosquito), and anti-plasmodial activities against Plasmodium falciparum and Plasmodium berghei .
Thujaplicins, as other tropolones, demonstrate chelating activity, acting as an ionophore by binding different metal ions.
Tropolone and thujaplicins exhibit potent suppressive activity on enzymatic browning due to inhibition of polyphenol oxidase and tyrosinase. This have been shown in experiments on different vegetables, fruits, mushrooms, plants and other agricultural products.Prevention of darkening has also been elicited on seafood products.
Owing to their antibacterial activities against various microbes colonizing and affecting the skin, thujaplicins are used in skin care and hair growth products, [ citation needed ]and are especially popular in Eastern Asia.
Hinokitiol is used in various oral care products, including toothpastes and oral sprays.
Due to its antifungal activity against Malassezia pachydermatis , it is used in eardrop formulations for external otitis in dogs.
Considering their antifungal activity against many plant-pathogenic fungi, and pesticidal and insecticidal properties, the role of thujaplicins in agriculture is evolving, including their use in the management of different plant diseases and for controlling the postharvest decay.
Thujaplicins are used as food additives in Japan.Due to its suppressive activity on food browning and the inhibitory activity against bacteria and fungi causing food spoilage (such as Clostridium perfringens , Alternaria alternata , Aspergillus niger , Botrytis cinerea , Fusobacterium species, Monilinia fructicola and Rhizopus stolonifer ), hinokitiol is also used in food packaging as a shelf-life extending agent.
Junipers are coniferous trees and shrubs in the genus Juniperus of the cypress family Cupressaceae. Depending on taxonomic viewpoint, between 50 and 67 species of junipers are widely distributed throughout the Northern Hemisphere, from the Arctic, south to tropical Africa, from Ziarat, Pakistan, east to eastern Tibet in the Old World, and in the mountains of Central America. The highest-known juniper forest occurs at an altitude of 16,000 ft (4,900 m) in southeastern Tibet and the northern Himalayas, creating one of the highest tree-lines on earth.
Thuja is a genus of coniferous trees in the Cupressaceae. There are five species in the genus, two native to North America and three native to eastern Asia. The genus is monophyletic and sister to Thujopsis. Members are commonly known as arborvitaes, thujas or cedars.
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 latinisation of the Greek κυπάρισσος (kyparissos).
Cupressaceae is a conifer family, the cypress family, with worldwide distribution. The family includes 27–30 genera, which include the junipers and redwoods, with about 130–140 species in total. They are monoecious, subdioecious or (rarely) dioecious trees and shrubs up to 116 m (381 ft) tall. The bark of mature trees is commonly orange- to red- brown and of stringy texture, often flaking or peeling in vertical strips, but smooth, scaly or hard and square-cracked in some species.
Cupressus nootkatensis is a species of trees in the cypress family native to the coastal regions of northwestern North America. This species goes by many common names including: Nootka cypress, yellow cypress, Alaska cypress, Nootka cedar, yellow cedar, Alaska cedar, and Alaska yellow cedar. The specific epithet "nootkatensis" is derived from its discovery by Europeans on the lands of a First Nation of Canada, those lands of the Nuu-chah-nulth people of Vancouver Island, British Columbia, who were formerly referred to as the Nootka.
Thuja plicata is an evergreen coniferous tree in the cypress family, Cupressaceae, native to western North America. Its common name is western redcedar and it is also called Pacific redcedar, giant arborvitae or western arborvitae, just cedar, giant cedar, or shinglewood,. It is not a true cedar of the genus Cedrus.
Xanthocyparis is a genus of cypresses in the family Cupressaceae. As of August 2021, it has only one species, Xanthocyparis vietnamensis, native to Vietnam and southeast China. It is commonly known as the Vietnamese golden cypress. The Nootka cypress, Cupressus nootkatensis or Callitropsis nootkatensis, was also placed in the genus, but this has been rejected.
The Sister Mary Grace Burns Arboretum, on the campus of Georgian Court University, in Lakewood Township, New Jersey, United States, was once the landscaped park for the winter home of George Jay Gould, millionaire son of railroad tycoon Jay Gould.
Ralph Alexander Raphael was a British organic chemist, well known for his use of acteylene derivatives in the synthesis of natural products with biological activity.
Monoterpenes are a class of terpenes that consist of two isoprene units and have the molecular formula C10H16. Monoterpenes may be linear (acyclic) or contain rings (monocyclic and bicyclic). Modified terpenes, such as those containing oxygen functionality or missing a methyl group, are called monoterpenoids. Monoterpenes and monoterpenoids are diverse. They have relevance to the pharmaceutical, cosmetic, agricultural, and food industries.
Tropolone is an organic compound with the formula C7H5(OH)O. It is a pale yellow solid that is soluble in organic solvents. The compound has been of interest to research chemists because of its unusual electronic structure and its role as a ligand precursor. Although not usually prepared from tropone, it can be viewed as its derivative with a hydroxyl group in the 2-position.
Callophrys gryneus, the juniper hairstreak or olive hairstreak, is a butterfly native to North America. It belongs in the family Lycaenidae.
Hinokitiol (β-thujaplicin) is a natural monoterpenoid found in the wood of trees in the family Cupressaceae. It is a tropolone derivative and one of the thujaplicins. Hinokitiol is used in oral and skin care products, and is a food additive used in Japan.
Cinara cupressi, the cypress aphid, is a brownish soft-bodied aphid. It sucks sap from twigs of conifers, and can cause damage to the tree, ranging from discoloring of the affected twig to the death of the tree. This insect appears to have originated in the Middle East and has been increasing its range and is considered to be an invasive species in Africa and Europe. It has been included in the List of the world's 100 worst invasive species.
Cedrol is a sesquiterpene alcohol found in the essential oil of conifers, especially in the genera Cupressus (cypress) and Juniperus (juniper). It has also been identified in Origanum onites, a plant related to oregano. Its main uses are in the chemistry of aroma compounds. It makes up about 19% of cedarwood oil Texas and 15.8% of cedarwood oil Virginia.
Mihrabat Nature Park is a nature park located on the Asian part in Beykoz district of Istanbul Province, Turkey.
Tetsuo Nozoe was a Japanese organic chemist. He is known for the discovery of hinokitiol, a seven-membered aromatic compound, and studying non-benzenoid aromatic compounds.