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Plicatic Acid
Plicatic acid is a carboxylic acid from the resin acid group. It is naturally found in '' Thuja'' and cypress resin. It is the main irritant and contact allergen present in thuja wood. (''Cf.'' pine, where the primary irritant is abietic acid.) The highest concentrations of plicatic acid can be found in ''Thuja plicata'' (Western Red cedar), but ''Thuja occidentalis'' (Eastern Arborvitae) and ''Cryptomeria japonica'' (Sugi) contain it in significant proportions as well. Exposure to plicatic acid or thuja wood dust can worsen asthma and provoke allergic reaction Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic derm ...s. References {{reflist O-methylated natural phenols Cupressaceae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboxylic Acid
In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic acids occur widely. Important examples include the amino acids and fatty acids. Deprotonation of a carboxylic acid gives a carboxylate anion. Examples and nomenclature Carboxylic acids are commonly identified by their trivial names. They at oftentimes have the suffix ''-ic acid''. IUPAC-recommended names also exist; in this system, carboxylic acids have an ''-oic acid'' suffix. For example, butyric acid (C3H7CO2H) is butanoic acid by IUPAC guidelines. For nomenclature of complex molecules containing a carboxylic acid, the carboxyl can be considered position one of the parent chain even if there are other substituents, such as 3-chloropropanoic acid. Alternately, it can be named as a "carboxy" or "carboxylic acid" substituent on another ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resin Acid
Resin acid refers to mixtures of several related carboxylic acids, primarily abietic acid, found in tree resins. Nearly all resin acids have the same basic skeleton: three fused rings having the empirical formula C19H29COOH. Resin acids are tacky, yellowish gums that are water-insoluble. They are used to produce soaps for diverse applications, but their use is being displaced increasingly by synthetic acids such as 2-ethylhexanoic acid or petroleum-derived naphthenic acids. Botanical analysis Resin acids are protectants and wood preservatives that are produced by parenchymatous epithelial cells that surround the resin ducts in trees from temperate coniferous forests. The resin acids are formed when two-carbon and three-carbon molecules couple with isoprene building units to form monoterpenes (volatile), sesquiterpenes (volatile), and diterpenes (nonvolatile) structures. Pines contain numerous vertical and radial resin ducts scattered throughout the entire wood. The accumulation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thuja
''Thuja'' ( ) is a genus of coniferous tree or shrub in the Cupressaceae (cypress family). 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 (from the Latin term for 'tree of life'), thujas or cedars. Description ''Thuja'' are evergreen trees growing from tall, with stringy-textured reddish-brown bark. The shoots are flat, with side shoots only in a single plane. The leaves are scale-like and long, except young seedlings in their first year, which have needle-like leaves. The scale leaves are arranged in alternating decussate pairs in four rows along the twigs. The male cones are small, inconspicuous, and are located at the tips of the twigs. The female cones start out similarly inconspicuous, but grow to about long at maturity when 6–8 months old; they have 6-12 overlapping, thin, leathery scales, each scale bearing 1–2 small se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, subdioecious or (rarely) dioecious trees and shrubs up to 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. Description The leaves are arranged either spirally, in decussate pairs (opposite pairs, each pair at 90° to the previous pair) or in decussate whorls of three or four, depending on the genus. On young plants, the leaves are needle-like, becoming small and scale-like on mature plants of many genera; some genera and species retain needle-like leaves throughout their lives. Old leaves are mostly not shed individually, but in small sprays of foliage (cladoptosis); exceptions are leaves on the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contact Allergen
An allergen is a type of antigen that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise be harmless to the body. Such reactions are called allergies. In technical terms, an allergen is an antigen that is capable of stimulating a type-I hypersensitivity reaction in atopic individuals through immunoglobulin E (IgE) responses. Most humans mount significant Immunoglobulin E responses only as a defense against parasitic infections. However, some individuals may respond to many common environmental antigens. This hereditary predisposition is called atopy. In atopic individuals, non-parasitic antigens stimulate inappropriate IgE production, leading to type I hypersensitivity. Sensitivities vary widely from one person (or from one animal) to another. A very broad range of substances can be allergens to sensitive individuals. Types of allergens Allergens can be found in a variety of sources, such as dust mite e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pine
A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accepts 187 species names of pines as current, together with more synonyms. The American Conifer Society (ACS) and the Royal Horticultural Society accept 121 species. Pines are commonly found in the Northern Hemisphere. ''Pine'' may also refer to the lumber derived from pine trees; it is one of the more extensively used types of lumber. The pine family is the largest conifer family and there are currently 818 named cultivars (or trinomials) recognized by the ACS. Description Pine trees are evergreen, coniferous resinous trees (or, rarely, shrubs) growing tall, with the majority of species reaching tall. The smallest are Siberian dwarf pine and Potosi pinyon, and the tallest is an tall ponderosa pine located in southern Oregon's Rogue Riv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abietic Acid
Abietic acid (also known as ''abietinic acid'' or ''sylvic acid'') is an organic compound that occurs widely in trees. It is the primary component of resin acid, is the primary irritant in pine wood and resin, isolated from rosin (via isomerization) and is the most abundant of several closely related organic acids that constitute most of rosin, the solid portion of the oleoresin of coniferous trees. Its ester or salt is called an ''abietate''.Lars-Hugo Norlin "Tall Oil" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. Preparation Abietic acid is extracted from tree rosin. The pure material is a colorless solid, but commercial samples are usually a glassy or partly crystalline yellowish solid that melts at temperatures as low as . It belongs to the abietane diterpene group of organic compounds derived from four isoprene units. It is used in lacquers, varnishes, and soaps, and for the analysis of resins and the preparation of metal resinates. It is foun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thuja Plicata
''Thuja plicata'' is an evergreen coniferous tree in the cypress family Cupressaceae, native to western North America. Its common name is western redcedar (western red cedar in the UK), and it is also called Pacific redcedar, giant arborvitae, western arborvitae, just cedar, giant cedar, or shinglewood. It is not a true cedar of the genus ''Cedrus''. Description ''Thuja plicata'' is a large to very large tree, ranging up to tall and in trunk diameter. Trees growing in the open may have a crown that reaches the ground, whereas trees densely spaced together will exhibit a crown only at the top, where light can reach the leaves. The trunk swells at the base and has shallow roots. The bark is thin, gray-brown and fissured into vertical bands. As the tree ages, the top is damaged by wind and replaced by inferior branches. The species is long-lived; some trees can live well over a thousand years, with the oldest verified aged 1,460. The foliage forms flat sprays with scale-like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thuja Occidentalis
''Thuja occidentalis'', also known as northern white-cedar, eastern white-cedar, or arborvitae, is an evergreen coniferous tree, in the cypress family Cupressaceae, which is native to eastern Canada and much of the north-central and northeastern United States. It is widely cultivated as an ornamental plant. Common names Its additional common names include swamp cedar, American arborvitae, and eastern arborvitae. The name arborvitae is particularly used in the horticultural trade in the United States; it is Latin for 'tree of life' – due to the supposed medicinal properties of the sap, bark, and twigs.''Thuja'', American Cancer Society, last revised 6/19/2007available online/ref> It is sometimes called white-cedar (hyphenated) or whitecedar (one word) to distinguish it from ''Cedrus'', a distantly related genus of trees also known as cedars. Description Unlike the closely related western red cedar (''Thuja plicata''), northern white cedar is only a small or medium-sized tree ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptomeria Japonica
''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'' L.f.). It used to be considered by some to be endemic to Japan (see remark below under 'Endemism'), where it is known as . The tree is called Japanese cedar or Japanese redwood in English. It has been extensively introduced and cultivated for wood production on the Azores. Description ''Cryptomeria'' is a very large evergreen tree, reaching up to tall and trunk diameter, with red-brown bark which peels in vertical strips. The leaves are arranged spirally, needle-like, long; and the seed cones globular, diameter with about 20–40 scales. It is superficially similar to the related giant sequoia (''Sequoiadendron giganteum''), from which it can be differentiated by the longer leaves (under in the giant sequoia) and smaller cones ( in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asthma
Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, coughing, chest tightness, and shortness of breath. These may occur a few times a day or a few times per week. Depending on the person, asthma symptoms may become worse at night or with exercise. Asthma is thought to be caused by a combination of genetic and environmental factors. Environmental factors include exposure to air pollution and allergens. Other potential triggers include medications such as aspirin and beta blockers. Diagnosis is usually based on the pattern of symptoms, response to therapy over time, and spirometry lung function testing. Asthma is classified according to the frequency of symptoms, forced expiratory volume in one second (FEV1), and peak expiratory flow rate. It may also be classified as atopic or non-atopic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allergic Reaction
Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic dermatitis, allergic asthma, and anaphylaxis. Symptoms may include red eyes, an itchy rash, sneezing, coughing, a runny nose, shortness of breath, or swelling. Note: food intolerances and food poisoning are separate conditions. Common allergens include pollen and certain foods. Metals and other substances may also cause such problems. Food, insect stings, and medications are common causes of severe reactions. Their development is due to both genetic and environmental factors. The underlying mechanism involves immunoglobulin E antibodies (IgE), part of the body's immune system, binding to an allergen and then to a receptor on mast cells or basophils where it triggers the release of inflammatory chemicals such as histamine. Diagnosis is ty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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