Classification (APG IV)
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Asterales
Family: Asteraceae
Genus: Tussilago
Species: Coltsfoot - Tussilago farfara L.

Botanical Description
Coltsfoot (Tussilago farfara) is a perennial, dioecious herbaceous plant from the Asteraceae family and the genus Tussilago. The plant typically grows 10–20 cm tall but can extend up to 40 cm when the flower-bearing stem elongates during seed development. Its fragrant flowers form solitary capitula at the top of the stems, with diameters ranging from 1–2 cm, occasionally up to 2.5 cm. The capitula consist of golden-yellow ray florets (female) at the periphery and bisexual, sterile disc florets in the center. The capitulum is surrounded by a cylindrical involucre that droops before and after flowering but becomes erect during bloom. Coltsfoot blooms from April to May and is pollinated by insects. [1]

The fruits are ribbed, elongated achenes measuring 2–4 mm and equipped with a pappus of white simple hairs for wind dispersal. The plant has scaly stem leaves that differ from its basal leaves. Stem leaves are membranous, scale-like, reddish-brown, and cover the flowering stem. Basal leaves, appearing after flowering, are large, kidney-shaped, with a cordate base, long petioles, and palmate venation. The leaves are somewhat leathery, light to dark green on the upper surface, and white-felted underneath. [1]

The aerial stems are erect, thick, unbranched, and elongate as fruits mature. They are covered with a network of woolly and glandular hairs. The underground part consists of a long, creeping, branched rhizome that is whitish to yellowish. Coltsfoot reproduces by seeds and vegetatively through numerous adventitious buds on the rhizome. [1]

Distribution
Coltsfoot is widespread in Europe, Western and Eastern Siberia, the Caucasus, the Far East, Central and Minor Asia, and the Himalayas. It has also naturalized in North America and India. In Estonia, coltsfoot is very common. The plant thrives in human-altered habitats such as roadsides, ditch banks, railway embankments, quarries, and wastelands. It is also found as a weed in fields and gardens, and occasionally in open coastal meadows and alvars. Coltsfoot prefers moist soils with clayey or sandy textures. [1]

Effects and Uses
Coltsfoot has long been valued as an important medicinal plant in folk medicine. It has been used worldwide to treat various respiratory diseases and has also been consumed as food. [2] It is considered an effective blood purifier, particularly for conditions like rheumatism and skin problems. Freshly crushed leaves are applied externally to treat wounds, burns, injuries, and even eye inflammations. [3,4]

Key bioactive compounds include polysaccharides with anti-inflammatory and immunostimulatory effects (e.g., mucopolysaccharides, pectin, and inulin), flavonoids with anti-inflammatory and antispasmodic properties (e.g., quercetin, kaempferol, their glycosides, and hyperoside), terpenes (e.g., tussilagon, α- and β-amyrin, farnesol, bisabolene epoxide), sterols, and phenolic acids. [3,4,5]

The whole plant can be used medicinally, but the leaves are most commonly harvested in spring and early summer when they are 8–15 cm in size. Leaves are dried in thin layers at 40–50°C without stirring. The recommended daily dose is 1.8–6 g of dried leaves. Coltsfoot is contraindicated during pregnancy and should not be used with cardiovascular medications. [6]

References
1. Author unknown. (n.d.). Coltsfoot (Paiseleht). Retrieved November 17, 2023, from BioEdu
2. Chen, S., et al. (2021). A review of the ethnobotanical value, phytochemistry, pharmacology, toxicity and quality control of Tussilago farfara L. (coltsfoot). Journal of Ethnopharmacology, 267, 113478. DOI:10.1016/j.jep.2020.113478
3. Nedelcheva, A., et al. (2015). Pyrrolizidine alkaloids in Tussilago farfara from Bulgaria. Biotechnology and Biotechnological Equipment, 29. DOI:10.1080/13102818.2015.1047149
4. Dehnam, A., Tobyn, G., & Whitelegg, M. (2011). Tussilago farfara, coltsfoot. DOI:10.1016/B978-0-443-10344-5.00035-5
5. Bota, V. B., et al. (2022). A Comparative Analysis of the Anatomy, Phenolic Profile, and Antioxidant Capacity of Tussilago farfara L. Vegetative Organs. Plants, 11(13). DOI:10.3390/plants11131663
6. Raal, A. (2010). Maailma ravimtaimede entsüklopeedia. Tallinn: Eesti Entsüklopeediakirjastus.

Süstemaatiline kuuluvus (APG IV)
Riik: Taimed (Plantae)
Klaad: Soontaimed (Tracheophyta)
Klaad: Katteseemnetaimed (Angiospermae)
Klaad: Päriskaheidulehelised (Eudicotyledonae)
Selts: Astrilaadsed (Asterales)
Sugukond: Korvõielised (Asteraceae)
Perekond: Paiseleht (Tussilago)
Liik: Paiseleht - Tussilago farfara L.

Botaaniline kirjeldus
Paiseleht on mitmeaastane ühekojaline suvehaljas rohttaim korvõieliste sugukonnast, perekonnast paiseleht. Taime kõrgus varieerub tavaliselt 10-20 cm vahel, kuid seemnete valmimise ajaks pikeneb õisikut kandev vars kuni 40 cm-ni. Selle lõhnavad õied moodustavad korvõisiku, mille läbimõõt jääb 1-2 cm piiresse, harvem kuni 2,5 cm. Õisikud paiknevad üksikult varre tipus. Servas asuvad kuldkollased keelõied ja keskel samavärvilised putkõied. Putkõied on mõlemasugulised ja ei vilju ning keelõied on viljuvad emasõied. Korvõisikuid katab ruljas üldkatis, mis on enne ja pärast õitsemist longus, kuid õitsemise ajal püstine. Paiseleht õitseb aprillist maini ning tolmleb putukate abil. [1]

Levila
Paiseleht on levinud laialdaselt Euroopas, Lääne- ja Ida-Siberis, Kaukaasias, Kaug-Idas, Kesk- ja Väike-Aasias ning Himaalajas. Ta on tulnukliigina levinud ka Põhja-Ameerikas ja Indias. Eestis on paiseleht väga tavaline. Paiseleht eelistab kasvada inimese tegevusest mõjutatud paikades, sealhulgas teeservadel, kraavikallastel, raudteetammidel, karjäärides ja jäätmaadel. Samuti leidub seda põldudel ja aedades umbrohuna ning mõnikord avatud mererannal, sealhulgas rannaniitudel ja pärisniitude lagedamatel aladel. Ta eelistab niisket, savika või liivaka tekstuuriga pinnast.  [1]

Toime ja kasutamine
Paiselehte on rahvameditsiinis pikka aega peetud oluliseks ravimtaimeks. Teda on ammustest aegadest paljudes maailma osades kasutatud erinevate hingamisteede haiguste raviks ning. Taime on tarbitud ka toiduks. [2] Paiselehte peetakse tõhusaks verepuhastusvahendiks, eriti juhtudel, kus esinevad reuma ja nahaprobleemid. Selle taime värskeid purustatud lehti kasutatakse välispidiselt haavade, põletuste, vigastuste ja isegi silmapõletike raviks. [3,4] Taimes sisalduvad peamised ühendid hõlmavad polüsahhariide, mis omavad põletikuvastast ja immunostimuleerivat toimet (nt mukopolüsahhariidid, pektiin ja inuliin), flavonoide, mis omavad põletikuvastast ja spasme leevendavat toimet (nt kvertsetiin, kempferool ja nende glükosiidid ning hüperosiid), terpeene (nttussilagoon, α- ja β-amüriin, faradiool, bisaboleenepoksiid), steroolid ning fenoolhapped. [3,4,5]

Droogiks sobib kogu taim, kuid enamasti korjatakse lehti. Need korjatakse kevadel ja suve hakul kui need on 8-15 cm suurused. Droog kuivatatakse 40-50 °C juures õhukese kihina. Kuivatamisel lehti ei segata. Päevane annus droogi on 1,8-6 g droogi. Vastunäidistatud rasedatele. Ei tohi tarvitada koos südame-ja veresoonkonna ravimitega. [6] 

Kasutatud allikad
1. Tundmatu autor. (n.d.). Paiseleht.  Retrieved November 17, 2023, from https://bio.edu.ee/taimed/oistaim/paiseleht.htm
2. Chen, S., Dong, L., Quan, H., Zhou, X., Ma, J., Xia, W., Zhou, H., & Fu, X. (2021). A review of the ethnobotanical value, phytochemistry, pharmacology, toxicity and quality control of Tussilago farfara L. (coltsfoot). Journal of ethnopharmacology, 267, 113478. https://doi.org/10.1016/j.jep.2020.113478
3. Nedelcheva, A., Kostova, N., & Sidjimov, A. (2015). Pyrrolizidine alkaloids in Tussilago farfara from Bulgaria. Biotechnology and Biotechnological Equipment, 29. https://doi.org/10.1080/13102818.2015.1047149 (20.09.2023) 
4. Dehnam, A., Tobyn, G., Whitelegg, M. (2011). Tussilago farfara, coltsfoot. https://doi.org/10.1016/B978-0-443-10344-5.00035-5 (20.09.2023) 
5. Bota, V. B., Neamtu, A. A., Olah, N. K., Chișe, E., Burtescu, R. F., Pripon Furtuna, F. R., Nicula, A. S., Neamtu, C., Maghiar, A. M., Ivănescu, L. C., Zamfirache, M. M., Mathe, E., & Turcuș, V. (2022). A Comparative Analysis of the Anatomy, Phenolic Profile, and Antioxidant Capacity of Tussilago farfara L. Vegetative Organs. Plants, 11(13). https://doi.org/10.3390/plants11131663 (20.09.2023)
6. Raal, A. (2010). Maailma ravimtaimede entsüklopeedia. Tallinn: Eesti Entsüklopeediakirjastus.