''Petasites'' is a genus of flowering plants in the sunflower family, Asteraceae, 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 shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...

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 whole plant – a herbaceous perennial growing from short, thick rhizo ...

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

Characteristics

The short spikes of flowers 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 a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

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

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

, and

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

, as well as Europe and

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

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

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 common neurological disorder characterized by recurrent headaches. Typically, the associated headache affects one side of the head, is pulsating in nature, may be moderate to severe in intensity, and could last from a few hou ...

prevention and treatment of allergic rhinitis, which have the most evidence for its effectiveness.

Migraine

Some butterbur species contain the chemicals

petasin Petasin is a natural chemical compound found in plants of the genus ''Petasites''. Chemically, it is classified as a sesquiterpene and is the ester of petasol and angelic acid Angelic acid is a Carboxylic acid, monocarboxylic Saturated and uns ...

and isopetasin which are believed to have potential benefits in treating

migraines Migraine (, ) is a common neurological disorder characterized by recurrent headaches. Typically, the associated headache affects one side of the head, is pulsating in nature, may be moderate to severe in intensity, and could last from a few hou ...

. 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, if taken four times daily. Butterbur was also shown to be comparably effective as fexofenadine 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. Pyrrolizidine alkaloids are produced by plants as a defense mechanism against insect he ...

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 called

CYP3A4 Cytochrome P450 3A4 (abbreviated CYP3A4) () is an important enzyme in the body, mainly found in the liver and in the intestine. It oxidizes small foreign organic molecules (xenobiotics), such as toxins or drugs, so that they can be removed from t ...

(i.e. St. John's wort, carbamazepine, phenytoin, rifampin); this interaction can potentially lead to increased concentration of the toxic alkaloids.

Species

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

Republic of Georgia A republic () is a "state in which power rests with the people or their representatives; specifically a state without a monarchy" and also a "government, or system of government, of such a state." Previously, especially in the 17th and 18th c ...

* ''

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

Petasites paradoxus ''Petasites'' is a genus of flowering plants in the sunflower family, Asteraceae, that are commonly referred to as butterburs and coltsfoots.Petasites pyrenaicus ''Petasites pyrenaicus'', the winter heliotrope, is a medicinal Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting ...

'' syn. ''Petasites fragrans'' - winter heliotrope - from Azores to Ireland + Tunisia * '' Petasites radiatus'' – Mongolia * '' Petasites rubellus'' – Mongolia, Manchuria, Korea * ''

Petasites sibiricus ''Petasites'' is a genus of flowering plants in the sunflower family, Asteraceae, that are commonly referred to as butterburs and coltsfoots.Petasites spurius ''Petasites spurius'' is a species of flowering plant in the family Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Comm ...

'' – Europe, Siberia, Caucasus, Central Asia * ''

Petasites tatewakianus ''Petasites'' is a genus of flowering plants in the sunflower family, Asteraceae, that are commonly referred to as butterburs and coltsfoots.Petasites tricholobus'' – China, Vietnam, Himalayas * ''

Petasites versipilus ''Petasites'' is a genus of flowering plants in the sunflower family, Asteraceae, that are commonly referred to as butterburs and coltsfoots.Sichuan, Yunnan ;Species of hybrid origin *''Petasites × vitifolius'' ;Species formerly included ''Petasites glacialis'' (Ledeb.) Polunin - ''

Endocellion ''Endocellion'' is a genus of flowering plants in the daisy family Asteraceae. There is only one accepted species, '' Endocellion glaciale'', native to eastern Russia ( Krasnoyarsk, Khabarovsk, Magadan Magadan ( rus, Магадан, p=mə ...

glaciale'' (Ledeb.) Toman

References

External links

Flora Europaea: ''Petasites'' species list and distributionseFloras search results: ''Petasites''
Visual identification and edible parts of sweet coltsfoot. {{Taxonbar, from=Q830156 Asteraceae genera Medicinal plants Taxa named by Philip Miller Dioecious plants