Emodin (6-methyl-1,3,8-trihydroxyanthraquinone) is a chemical compound, of the anthraquinone family, that can be isolated from

rhubarb Rhubarb is the fleshy, edible stalks ( petioles) of species and hybrids (culinary rhubarb) of ''Rheum'' in the family Polygonaceae, which are cooked and used for food. The whole plant – a herbaceous perennial growing from short, thick rhizo ...

buckthorn ''Rhamnus'' is a genus of about 110 accepted species of shrubs or small trees, commonly known as buckthorns, in the family Rhamnaceae. Its species range from tall (rarely to ) and are native mainly in east Asia and North America, but found thr ...

, and Japanese knotweed (''

Reynoutria japonica ''Reynoutria japonica'', synonyms ''Fallopia japonica'' and ''Polygonum cuspidatum'', is a species of herbaceous perennial plant in the knotweed and buckwheat family Polygonaceae. Common names include Japanese knotweed and Asian knotweed. It is ...

'' syn. ''Polygonum cuspidatum''). Emodin is particularly abundant in the roots of the Chinese rhubarb (Rheum palmatum), knotweed and knotgrass (

Polygonum ''Polygonum'' is a genus of about 130 species of flowering plant in the buckwheat and knotweed family Polygonaceae. Common names include knotweed and knotgrass (though the common names may refer more broadly to plants from Polygonaceae). In the ...

cuspidatum and multiflorum) as well as Hawaii ‘au‘auko‘i cassia seeds or coffee weed (Semen cassia). It is specifically isolated from Rheum palmatum L. It is also produced by many species of fungi, including members of the genera ''

Aspergillus ' () is a genus consisting of several hundred mold species found in various climates worldwide. ''Aspergillus'' was first catalogued in 1729 by the Italian priest and biologist Pier Antonio Micheli. Viewing the fungi under a microscope, Miche ...

'', ''

Pyrenochaeta Pyrenochaeta is a genus of fungus. It includes the species '' Pyrenochaeta romeroi''. Can cause a disease called eumycetoma Eumycetoma, also known as Madura foot, is a persistent fungal infection of the skin and the tissues just under the ...

'', and ''

Pestalotiopsis ''Pestalotiopsis'' is a genus of ascomycete fungi. ''Pestalotiopsis'' species are known as plant pathogens. The genus name of ''Pestalotiopsis'' is in honour of Fortunato Pestalozza (died 1878), who was an Italian botanist and doctor who worked ...

'', inter alia. The common name is derived from ''Rheum emodi'', a

taxonomic synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linnae ...

of ''

Rheum australe ''Rheum australe'', synonym ''Rheum emodi'', is a flowering plant in the family Polygonaceae. It is commonly known as Himalayan rhubarb, Indian rhubarb and Red-veined pie plant. It is a medicinal herb used in the Indian Unani system of medici ...

'', (Himalayan rhubarb) and synonyms include emodol, frangula emodin, rheum emodin, 3-methyl-1,6,8-trihydroxyanthraquinone, Schüttgelb (Schuttgelb), and Persian Berry Lake.

Pharmacology

Emodin is an active component of several plants used in

Traditional Chinese Medicine Traditional Chinese medicine (TCM) is an alternative medical practice drawn from traditional medicine in China. It has been described as "fraught with pseudoscience", with the majority of its treatments having no logical mechanism of action ...

(TCM) such as ''

Rheum palmatum ''Rheum palmatum'' is a species of flowering plant in the knotweed family Polygonaceae. It is commonly called Chinese rhubarb, ornamental rhubarb, Turkey rhubarb or East Indian rhubarb. ''Rheum palmatum'' is a herbaceous perennial related to th ...

'', '' Polygonum cuspidatum'' and '' Polygonum multiflorum''. It has various actions including

laxative Laxatives, purgatives, or aperients are substances that loosen stools and increase bowel movements. They are used to treat and prevent constipation. Laxatives vary as to how they work and the side effects they may have. Certain stimulant, lubri ...

antibacterial An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...

and

antiinflammatory Anti-inflammatory is the property of a substance or treatment that reduces inflammation or swelling. Anti-inflammatory drugs, also called anti-inflammatories, make up about half of analgesics. These drugs remedy pain by reducing inflammation as o ...

effects, and has also been identified as having potential

antiviral Antiviral drugs are a class of medication used for treating viral infections. Most antivirals target specific viruses, while a broad-spectrum antiviral is effective against a wide range of viruses. Unlike most antibiotics, antiviral drugs do no ...

activity against

coronavirus Coronaviruses are a group of related RNA viruses that cause diseases in mammals and birds. In humans and birds, they cause respiratory tract infections that can range from mild to lethal. Mild illnesses in humans include some cases of the com ...

es such as

SARS-CoV-2 Severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) is a strain of coronavirus that causes COVID-19 (coronavirus disease 2019), the respiratory illness responsible for the ongoing COVID-19 pandemic. The virus previously had a ...

, being one of the major active components of the antiviral TCM formulation Lianhua Qingwen. A computational study was conducted to investigate the inhibition mechanism on the formation of the Spike-ACE2 protein complex. Specifically, it is seen dose-dependent inhibition in the prevention of infection by the

SARS-Cov-1 Severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1; or Severe acute respiratory syndrome coronavirus, SARS-CoV) is a strain of coronavirus that causes severe acute respiratory syndrome (SARS), the respiratory illness responsible for ...

whose evidence has stimulated further investigations on

SARS-Cov-2 Severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) is a strain of coronavirus that causes COVID-19 (coronavirus disease 2019), the respiratory illness responsible for the ongoing COVID-19 pandemic. The virus previously had a ...

. Emodin has been shown to inhibit the ion channel of protein 3a which could play a crucial role in the release of the virus from infected cells.

List of plant species

The following plant species produce emodin: * '' Acalypha australis'' * ''

Cassia occidentalis Cassia typically refers to cassia bark, the spice made from the bark of East Asian evergreen trees. Cassia may also refer to: Plants ;Cinnamon trees * ''Cinnamomum cassia'' (, ''ròuguì''), the cassia or Chinese cinnamon, found in southern Chin ...

'' * ''

Cassia siamea ''Senna siamea'', also known as Siamese cassia, kassod tree, cassod tree and cassia tree, is a legume in the subfamily Caesalpinioideae. It is native to South and Southeast Asia, although its exact origin is unknown. It is a medium-size, ev ...

'' *''

Frangula alnus ''Frangula alnus'', commonly known as alder buckthorn, glossy buckthorn, or breaking buckthorn, is a tall deciduous shrub in the family Rhamnaceae. Unlike other "buckthorns", alder buckthorn does not have thorns. It is native to Europe, northern ...

'' * ''

Glossostemon bruguieri ''Glossostemon bruguieri'' or ''Dombeya arabica'' is a species of flowering plant in the family Malvaceae. It is a shrub with thick long tapering dark colored roots with 70–100 cm in length and 5–8 cm in breadth, found in Yemen, Ir ...

'' * ''

Kalimeris indica ''Kalimeris indica'', also known as Indian aster or Indian Kalimeris, is a flowering herbaceous perennial plant of the family Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering pl ...

'' * ''Polygonum hypoleucum'' * ''

'' ( syn. ''Fallopia japonica'') (syn. ''Polygonum cuspidatum'') * ''

Rhamnus alnifolia ''Rhamnus alnifolia'' is a species of flowering plant in the buckthorn family known by the common names alderleaf buckthorn, or alder buckthorn. Unlike other "buckthorns", this alder buckthorn does not have thorns. It is native to North America ...

'', the alderleaf buckthorn * ''

Rhamnus cathartica ''Rhamnus cathartica'', the European buckthorn, common buckthorn, purging buckthorn, or just buckthorn, is a species of small tree in the flowering plant family Rhamnaceae. It is native to Europe, northwest Africa and western Asia, from the cen ...

'', the common buckthorn * ''

'' * ''Rumex nepalensis'' * ''

Senna obtusifolia ''Senna obtusifolia'', known by the common names Chinese senna, American sicklepod, sicklepod, etc., is a plant in the genus '' Senna'', sometimes separated in the monotypic genus ''Diallobus''. It grows wild in North, Central, and South America, ...

'' (syn. ''Cassia obtusifolia'') * '' Thielavia subthermophila'' * ''Ventilago madraspatana''

Compendial status

British Pharmacopoeia The ''British Pharmacopoeia'' (''BP'') is the national pharmacopoeia of the United Kingdom. It is an annually published collection of quality standards for medicinal substances in the UK, which is used by individuals and organisations involve ...

List of compounds with carbon number 15 This is a partial list of molecules that contain 15 carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bo ...

References

{{Purinergics Trihydroxyanthraquinones Virucides Resorcinols 3-Hydroxypropenals within hydroxyquinones