Orcein, also archil, orchil, lacmus and C.I. Natural Red 28, are names for dyes extracted from several species of lichen, commonly known as "orchella weeds", found in various parts of the world. A major source is the archil lichen, Roccella tinctoria . [1] Orcinol is extracted from such lichens. It is then converted to orcein by ammonia and air. In traditional dye-making methods, urine was used as the ammonia source. If the conversion is carried out in the presence of potassium carbonate, calcium hydroxide, and calcium sulfate (in the form of potash, lime, and gypsum in traditional dye-making methods), the result is litmus, a more complex molecule. [2] The manufacture was described by Cocq in 1812 [3] and in the UK in 1874. [4] Edmund Roberts noted orchilla as a principal export of the Cape Verde islands, superior to the same kind of "moss" found in Italy or the Canary Islands, that in 1832 was yielding an annual revenue of $200,000. [5] : pp.14, 15 Commercial archil is either a powder (called cudbear) or a paste. It is red in acidic pH and blue in alkaline pH.
The chemical components of orcein were elucidated only in the 1950s by Hans Musso. [6] The structures are shown below. A paper originally published in 1961, embodying most of Musso's work on components of orcein and litmus, was translated into English and published in 2003 [7] in a special issue of the journal Biotechnic & Histochemistry (Vol 78, No. 6) devoted to the dye. A single alternative structural formula for orcein, possibly incorrect, is given by the National Library of Medicine [8] and Emolecules. [9]
Orcein is a reddish-brown dye, orchil is a purple-blue dye. Orcein is also used as a stain in microscopy to visualize chromosomes, [10] elastic fibers, [11] Hepatitis B surface antigens, [12] and copper-associated proteins. [13]
Orcein is not approved as a food dye (banned in Europe since January 1977), with E number E121 before 1977 and E182 after. [14] [15] Its CAS number is . Its chemical formula is C28H24N2O7. It forms dark brown crystals. It is a mixture of phenoxazone derivates - hydroxyorceins, aminoorceins, and aminoorceinimines.
Cudbear is a dye extracted from orchil lichens that produces colours in the purple range. It can be used to dye wool and silk, without the use of mordant. The lichen is first boiled in a solution of ammonium carbonate. The mixture is then cooled and ammonia is added and the mixture is kept damp for 3–4 weeks. Then the lichen is dried and ground to powder.
Cudbear was the first dye to be invented in modern times, and one of the few dyes to be credited to a named individual: Dr Cuthbert Gordon of Scotland: production began in 1758, and it was patented in 1758, British patent 727. [16] [17] John Glassford invested in the new process with funds from his slave-labor tobacco business by establishing a dyeworks in Dennistoun in 1777. [18] [19] The manufacture details were carefully protected, with a ten-feet high wall being built around the manufacturing facility, and staff consisting of Highlanders sworn to secrecy. [18] The lichen consumption soon reached 250 tons per year and import from Norway and Sweden had to be arranged. [20]
A similar process was developed in France. The lichen is extracted by urine or ammonia, then the extract is acidified, the dissolved dye precipitates out and is washed. Then it is dissolved in ammonia again, the solution is heated in air until it becomes purple, then it is precipitated out with calcium chloride. The resulting insoluble purple solid is known as French purple, a fast lichen dye that was much more stable than other lichen dyes.
Violet is the color of light at the short wavelength end of the visible spectrum. It is one of the seven colors that Isaac Newton labeled when dividing the spectrum of visible light in 1672. Violet light has a wavelength between approximately 380 and 435 nanometers. The color's name is derived from the Viola genus of flowers.
Purple is a color similar in appearance to violet light. In the RYB color model historically used in the arts, purple is a secondary color created by combining red and blue pigments in different proportions. In the CMYK color model used in modern printing, purple is made by combining magenta pigment with either cyan pigment, black pigment, or both. In the RGB color model used in computer and television screens, purple is created by mixing red and blue light in order to create colors that appear similar to violet light.
Haematoxylin or hematoxylin, also called natural black 1 or C.I. 75290, is a compound extracted from heartwood of the logwood tree with a chemical formula of C
16H
14O
6. This naturally derived dye has been used as a histologic stain, as an ink and as a dye in the textile and leather industry. As a dye, haematoxylin has been called palo de Campeche, logwood extract, bluewood and blackwood. In histology, haematoxylin staining is commonly followed by counterstaining with eosin. When paired, this staining procedure is known as H&E staining and is one of the most commonly used combinations in histology. In addition to its use in the H&E stain, haematoxylin is also a component of the Papanicolaou stain which is widely used in the study of cytology specimens.
Sodium carbonate is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield alkaline solutions in water. Historically, it was extracted from the ashes of plants grown in sodium-rich soils. Because the ashes of these sodium-rich plants were noticeably different from ashes of wood, sodium carbonate became known as "soda ash". It is produced in large quantities from sodium chloride and limestone by the Solvay process, as well as by carbonating sodium hydroxide which is made using the Chlor-alkali process.
Alizarin is an organic compound with formula C
14H
8O
4 that has been used throughout history as a prominent red dye, principally for dyeing textile fabrics. Historically it was derived from the roots of plants of the madder genus. In 1869, it became the first natural dye to be produced synthetically.
Romanowsky staining, also known as Romanowsky–Giemsa staining, is a prototypical staining technique that was the forerunner of several distinct but similar stains widely used in hematology and cytopathology. Romanowsky-type stains are used to differentiate cells for microscopic examination in pathological specimens, especially blood and bone marrow films, and to detect parasites such as malaria within the blood. Stains that are related to or derived from the Romanowsky-type stains include Giemsa, Jenner, Wright, Field, May–Grünwald and Leishman stains. The staining technique is named after the Russian physician Dmitri Leonidovich Romanowsky (1861–1921), who was one of the first to recognize its potential for use as a blood stain.
Hematoxylin and eosin stain is one of the principal tissue stains used in histology. It is the most widely used stain in medical diagnosis and is often the gold standard. For example, when a pathologist looks at a biopsy of a suspected cancer, the histological section is likely to be stained with H&E.
Litmus is a water-soluble mixture of different dyes extracted from lichens. It is often absorbed onto filter paper to produce one of the oldest forms of pH indicator, used to test materials for acidity. In an acidic medium, blue litmus paper turns red, while in a basic or alkaline medium, red litmus paper turns blue.
Ethnolichenology is the study of the relationship between lichens and people. Lichens have and are being used for many different purposes by human cultures across the world. The most common human use of lichens is for dye, but they have also been used for medicine, food and other purposes.
For the parent molecule 9,10-anthraquinone, see anthraquinone
Lawsone (2-hydroxy-1,4-naphthoquinone), also known as hennotannic acid, is a red-orange dye present in the leaves of the henna plant, for which it is named, as well as in the common walnut and water hyacinth. Humans have used henna extracts containing lawsone as hair and skin dyes for more than 5,000 years. Lawsone reacts chemically with the protein keratin in skin and hair via a Michael addition reaction, resulting in a strong permanent stain that lasts until the skin or hair is shed. Darker colored staining is due to more lawsone–keratin interactions occurring, which evidently break down as the concentration of lawsone decreases and the tattoo fades. Lawsone strongly absorbs UV light, and aqueous extracts can be effective sunless tanning agents and sunscreens. Lawsone is a 1,4-naphthoquinone derivative, an analog of hydroxyquinone containing one additional ring.
Turnsole, katasol, or folium was a dyestuff prepared from the annual plant Chrozophora tinctoria.
γ-Amino-β-hydroxybutyric acid (GABOB), also known as β-hydroxy-γ-aminobutyric acid (β-hydroxy-GABA), and sold under the brand name Gamibetal among others, is an anticonvulsant which is used for the treatment of epilepsy in Europe, Japan, and Mexico. It is a GABA analogue, or an analogue of the neurotransmitter γ-aminobutyric acid (GABA), and has been found to be an endogenous metabolite of GABA.
Orcinol is an organic compound with the formula CH3C6H3(OH)2. It occurs in many species of lichens including Roccella tinctoria and Lecanora. Orcinol has been detected in the "toxic glue" of the ant species Camponotus saundersi. It is a colorless solid. It is related to resorcinol, 1,3-C6H4(OH)2.
Chrozophora tinctoria is a plant species native to the Mediterranean, the Middle East, India, Pakistan, and Central Asia. It is also present as a weed in North America and Australia.
The Biological Stain Commission (BSC) is an organization that provides third-party testing and certification of dyes and a few other compounds that are used to enhance contrast in specimens examined in biological and medical laboratories.
Anthraquinone dyes are an abundant group of dyes comprising a anthraquinone unit as the shared structural element. Anthraquinone itself is colourless, but red to blue dyes are obtained by introducing electron donor groups such as hydroxy or amino groups in the 1-, 4-, 5- or 8-position. Anthraquinone dyestuffs are structurally related to indigo dyestuffs and are classified together with these in the group of carbonyl dyes.
Dyeing is the craft of imparting colors to textiles in loose fiber, yarn, cloth or garment form by treatment with a dye. Archaeologists have found evidence of textile dyeing with natural dyes dating back to the Neolithic period. In China, dyeing with plants, barks and insects has been traced back more than 5,000 years. Natural insect dyes such as Tyrian purple and kermes and plant-based dyes such as woad, indigo and madder were important elements of the economies of Asia and Europe until the discovery of man-made synthetic dyes in the mid-19th century. Synthetic dyes quickly superseded natural dyes for the large-scale commercial textile production enabled by the industrial revolution, but natural dyes remained in use by traditional cultures around the world.
Stains-all is a carbocyanine dye, which stains anionic proteins, nucleic acids, anionic polysaccharides and other anionic molecules.
Laccaic acids or laccainic acids are a group of five anthraquinone derivatives, rated from A to E, constituting the red shellac obtained from the cochineal Kerria lacca, just like carminic acid or kermesic acid. For this article, it will mostly concentrate on the laccaic acid A (LCA).