''Petasites'' is a genus of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s in the sunflower family,

Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...

, that are commonly referred to as butterburs and coltsfoots.''Petasites''.
Flora of North America. Volume 20, Page 635. efloras.org. They are perennial plants with thick, creeping underground

rhizome In botany and dendrology, a rhizome ( ) is a modified subterranean plant stem that sends out roots and Shoot (botany), shoots from its Node (botany), nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from ...

s and large

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 plant is a herbaceous perennial that grows from short, thick rhizomes. ...

-like leaves during the growing season. Most species are native to Asia or southern Europe.

Taxonomy

The genus name is derived from the Greek word ''petasos'', from the plant's broad leaves resembling a wide-brimmed hat.

Species

;Accepted species * '' Petasites albus'' – white butterbur – Europe, Algeria, Turkey,

Caucasus The Caucasus () or Caucasia (), is a region spanning Eastern Europe and Western Asia. It is situated between the Black Sea and the Caspian Sea, comprising parts of Southern Russia, Georgia, Armenia, and Azerbaijan. The Caucasus Mountains, i ...

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

* '' Petasites fominii'' – Republic of Georgia * '' Petasites formosanus'' –

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...

* '' Petasites frigidus'' – Arctic butterbur or Arctic sweet coltsfoot – Scandinavia, Mongolia, Canada, northern USA * '' Petasites hybridus'' – common butterbur – Europe, Mediterranean * '' Petasites japonicus'' – giant butterbur, fuki – China, Japan, Korea * ''

Petasites kablikianus ''Petasites'' is a genus of flowering plants in the sunflower family, Asteraceae, that are commonly referred to as butterburs and coltsfoots.Petasites kamengicus'' –

Arunachal Pradesh Arunachal Pradesh (; ) is a States and union territories of India, state in northeast India. It was formed from the North-East Frontier Agency (NEFA) region, and India declared it as a state on 20 February 1987. Itanagar is its capital and la ...

* '' Petasites paradoxus'' – central + southwestern Europe from Spain to Poland * '' Petasites pyrenaicus'' syn. ''Petasites fragrans'' - winter heliotrope - from Azores to Ireland + Tunisia * '' Petasites radiatus'' – Mongolia * '' Petasites rubellus'' – Mongolia, Manchuria, Korea * '' Petasites sibiricus'' – Siberia * '' Petasites spurius'' – Europe, Siberia, Caucasus, Central Asia * '' Petasites tatewakianus'' – Siberia, Russian Far East, northeastern China * '' Petasites tricholobus'' – China, Vietnam, Himalayas * '' Petasites versipilus'' –

Sichuan Sichuan is a province in Southwestern China, occupying the Sichuan Basin and Tibetan Plateau—between the Jinsha River to the west, the Daba Mountains to the north, and the Yunnan–Guizhou Plateau to the south. Its capital city is Cheng ...

Yunnan Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...

;Species of hybrid origin *''Petasites × vitifolius'' ;Species formerly included ''Petasites glacialis'' (Ledeb.) Polunin - '' Endocellion glaciale'' (Ledeb.) Toman

Characteristics

The short spikes of

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s are produced just before the leaves in late winter (e.g. '' Petasites fragrans'') or spring, emerging with only a few elongated basal bracts and are usually green, flesh coloured or dull white depending on the species. It is

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

, with male and female flowers borne on separate plants. Butterbur can be found in parts of

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

such as

Korea Korea is a peninsular region in East Asia consisting of the Korean Peninsula, Jeju Island, and smaller islands. Since the end of World War II in 1945, it has been politically Division of Korea, divided at or near the 38th parallel north, 3 ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

, and

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

, as well as

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

and

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

. They prefer moist environments such as riverbanks, marshes and ditches. ''Petasites'' is closely related to the genera '' Tussilago'' and ''

Senecio ''Senecio'' is a genus of flowering plants in the daisy family (Asteraceae) that includes ragworts and groundsels. Variously circumscribed taxonomically, the genus ''Senecio'' is one of the largest genera of flowering plants. Description Mo ...

''.

Medicinal uses

Butterbur has been used for over 2000 years to treat a variety of ailments including fever, lung disease, spasms, and pain. Currently, butterbur extract is used for

migraine Migraine (, ) is a complex neurological disorder characterized by episodes of moderate-to-severe headache, most often unilateral and generally associated with nausea, and light and sound sensitivity. Other characterizing symptoms may includ ...

prevention and treatment of

allergic rhinitis Allergic rhinitis, of which the seasonal type is called hay fever, is a type of inflammation in the nose that occurs when the immune system overreacts to allergens in the air. It is classified as a type I hypersensitivity reaction. Signs a ...

, which have the most evidence for its effectiveness.

Migraine

Some butterbur species contain the chemicals petasin and isopetasin which are believed to have potential benefits in treating

migraines Migraine (, ) is a complex neurological disorder characterized by episodes of moderate-to-severe headache, most often unilateral and generally associated with nausea, and light and sound sensitivity. Other characterizing symptoms may includ ...

. High concentrations of petasin occur in both butterbur root and leaves, with the leaves containing lower levels of the toxic chemical. Butterbur extracts have been reported to be effective in reducing frequency and severity of

headaches. Several double-blind studies have shown that high doses of ''Petasites hybridus ''extract'', ''containing petasin and/or isopetasin, are effective both in preventing and in relieving migraine, with the best results in groups taking the higher dose of the supplement. Although mainly well tolerated, the adverse effects of butterbur reported in clinical trials include mainly gastrointestinal problems, such as nausea, flatulence, and belching. In 2015, the American Academy of Neurology withdrew its original endorsement of butterbur due to safety concerns. However, the Canadian Headache Society still recommends its use in migraine prevention for a selected number of patients based on their clinical features and co-existing disorders.

Hay fever or allergic rhinitis

Additionally, a study showed butterbur extract to be an effective treatment for hay fever without the sedative effect of the antihistamine

cetirizine Cetirizine is a second-generation antihistamine, second-generation Peripherally selective antihistamine used to treat allergic rhinitis (hay fever), dermatitis, and urticaria (hives). It is taken by mouth. Effects generally begin within thirty ...

, if taken four times daily. Butterbur was also shown to be comparably effective as

fexofenadine Fexofenadine, sold under the brand name Allegra among others, is an antihistamine medication used in the treatment of allergy symptoms such as allergic rhinitis and urticaria. Therapeutically, fexofenadine is a selective peripheral H1 blocke ...

when compared to placebo for reducing symptoms of allergic rhinitis.

Risks

Butterbur extracts may contain harmful components called

pyrrolizidine alkaloid Pyrrolizidine alkaloids (PAs), sometimes referred to as necine bases, are a group of naturally occurring alkaloids based on the structure of pyrrolizidine. Their use dates back centuries and is intertwined with the discovery, understanding, and e ...

s if the preparations are not carefully and fully purified. The concentration of the toxic alkaloids is often highest in the

rhizomes In botany and dendrology, a rhizome ( ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...

and lowest in the leaves, and may vary depending on where the plants are grown. These chemicals are toxic to the liver and may cause cancers. Thus, due to the potential for contamination, taking butterbur supplements is not recommended during pregnancy or breastfeeding. Some sources say it is safe practice to consume butterbur extract that has been prepared by a reputable laboratory. Other sources say no butterbur product is safe: "The cases of liver toxicity appear to have occurred with extracts of butterbur where the

s had been removed and only small amounts remained. There is some evidence that other constituents found in butterbur such as the sesquiterpene constituents for example petasin may be implicated in the liver toxicity". Long-term health effects and interaction of butterbur with other drugs have not been well documented. However, it can theoretically interact with certain blood pressure and heart medications, as well as with drugs that can induce a liver

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

called

CYP3A4 Cytochrome P450 3A4 (abbreviated CYP3A4) () is an important enzyme in the body, mainly found in the liver and in the intestine, which in humans is encoded by ''CYP3A4'' gene. It organic redox reaction, oxidizes small foreign organic molecules ( ...

(i.e.

St. John's wort ''Hypericum perforatum'', commonly known as St. John's wort (sometimes perforate St. John's wort or common St. John's wort), is a flowering plant in the family Hypericaceae. It is a hairless, Perennial, perennial herb with woody Root, roots, y ...

carbamazepine Carbamazepine, sold under the brand name Tegretol among others, is an anticonvulsant medication used in the treatment of epilepsy and neuropathic pain. It is used as an adjunctive treatment in schizophrenia along with other medications and as ...

phenytoin Phenytoin (PHT), sold under the brand name Dilantin among others, is an anticonvulsant, anti-seizure medication. It is useful for the prevention of tonic-clonic seizures (also known as grand mal seizures) and focal seizures, but not absence se ...

rifampin Rifampicin, also known as rifampin, is an ansamycin antibiotic used to treat several types of bacterial infections, including tuberculosis (TB), ''Mycobacterium avium'' complex, leprosy, and Legionnaires' disease. It is almost always used tog ...

); this interaction can potentially lead to increased concentration of the toxic alkaloids.

References

External links

Flora Europaea: ''Petasites'' species list and distributionseFloras search results: ''Petasites''
Visual identification and edible parts of sweet coltsfoot. {{Authority control Asteraceae genera Medicinal plants Taxa named by Philip Miller Dioecious plants