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Tussilago farfara L.

Description

Perennial plant (lives several years), between 10 and 30 cm high, with thick and fleshy rhizome. The stem, subway (rhizome), develops fine roots towards the ground, while towards the surface emerge several stems covered with scales that culminate in a flower head (a flower like a daisy, with a central rosette surrounded by many petals), without leaves. These are formed later, directly from the rhizome, all from the same point, with a long grooved petiole, and the heart-shaped blade (the flat surface of the leaf), with serrated edges, green on the upper side and white on the underside, is covered with a thick layer of hairs. This characteristic of the flower appearing before the leaves, earned it the nickname of filius ante patrem (the son before the father) during the Middle Ages. The floral scapes of 10-30 cm, ending in solitary capitula, 1.5-3.5cm in diameter, inserted on a thick and scaly stem, surrounded by reddish bracts, with yellow flowers, ligulate on the periphery and flosculose in the center. Capitula drooping after flowering, which become erect when the fruit ripens. The fruits are achenes with white villus, carrying filaments that facilitate dispersal by the wind. It belongs to the Asteraceae family (=Compositae).

Habitat and collection: It is found in moist clay soils of northern, central and eastern Spain. Harvesting: the chapters in February-April, before they open, and the leaves in May-June.

It is also known by the names of: farfara, horse's foot, horse's claw. The Latin word "tussis" means cough and "agere" means to chase away. Therefore, we can say that tusilago chases away coughs. Moreover, the plant was called in Greek "becltion" (pronounced "bequíon"), and as it fought cough, the Castilian language has inherited this meaning and calls "béquico" to any compound that acts against cough. As for farfara, it comes from the Latin "far" meaning flour and "fero" meaning to carry, alluding to the leaves, whose underside is covered with a dense white hair.

Part used

Leaves and flower heads.

Active ingredients

  • Mucilages (6-10%).
  • Tannins (up to 20%).
  • Terpenic alcohols: arnidiol and faradiol.
  • Flavonoids: rutoside, hyperoside.
  • Inulin (15% approximately).
  • Potassium nitrate and zinc salts.
  • Traces of pyrrolizidine alkaloids: two unsaturated necine esters, senkirkine (majority) and senecionine, as well as two saturated pyrrolizidines that are only artifacts due to methanol extraction, tusilagine (especially in younger flowers) and isotusilagine.
  • Bicyclic terpene esters of the nofonipetrone group and a sesquiterpene ester, tusilagone.
  • Phytosterols.
  • Essential oil in small quantities.
  • Bitter principles of tonic character.

Pharmacological action

  • Cough sedative or antitussive (mucilage, bitter principles).
  • Expectorant and fluidizing of bronchial secretion. Tussilage increases the activity of the hair cells that line the bronchial tubes, helping to expel mucus and debris trapped in the cilia.
  • Demulcent (mucilage).
  • Antimicrobial (tannins and terpenic alcohols).
  • Osmotic diuretic (inulin).
  • Anti-inflammatory (tannins).
  • Antispasmodic (flavonoids, organic acids).
  • Astringent (tannins).
  • Some authors consider it sudorific.

Indications

  • Respiratory affections: catarrh, pharyngitis, laryngitis or tracheitis, irritative cough, hoarseness, bronchitis, asthma, pulmonary emphysema, etc.
  • Stomatitis.

Contraindications

Although the alkaloid content is very low (less than 50 ppm), it is recommended to avoid its prescription during pregnancy, lactation, liver failure, viral hepatitis or liver cirrhosis, neoplasms. Especially in young leaves there are traces of a pyrrolizidine alkaloid, senkirkine, which acts as a hepatotoxic and potentially carcinogenic, especially in sensitive individuals.

Do not use in prolonged treatments.

Precautions and drug interactions

The average daily dose of 4.5-6 g of the drug, or the equivalent amount of its preparations. The daily intake of pyrrolizidine alkaloids of the 1,2 unsaturated necine type (including its N-oxides) should be less than 10 micrograms when the drug is administered or 1 microgram in the case of extracts or fresh plant juice.

Side effects and toxicity

Although the hepatotoxicity, genotoxicity and carcinogenicity of some pyrrolizidine alkaloids are known, the use of tusilago at the proposed doses does not present risks of acute toxicity, since these alkaloids pass into the infusion in minimal concentrations (one cup contains approximately 1 ppm). However, according to recent studies, continued use does not exclude the possibility of liver damage. The cure should be limited to 2-4 weeks.

The root contains much higher levels of these alkaloids than the leaves or flowers. Animal studies using hundreds of times higher amounts of thylakoids than those used as a medicine have shown that these alkaloids can cause cancer in animals; this does not apply to the amounts used as a medicine. Only one case has been described of a newborn who developed liver disease and died, and whose mother had drunk tusilago tea during pregnancy. This led to a ban on the use of tusilage in Germany in 1992.

The dangerousness of the use of tusilage is unclear. The only cases of poisoning initially attributed to tusilage were found to be due to counterfeiting by Petasites hybridus L. (P. Gaertner, Meyer et Scherb.) or confusion with Adenostyles alliariae (Gouan) Kern.

Studies

Study on antimicrobial activity: antimicrobiana:

Kokoska L, Polesny Z, Rada V, Nepovim A, Vanek T. Department of Tropical and Subtropical Crops, Czech University of Agriculture, Kamycka 129, Prague 6-Suchdol, Czech Republic. Screening of some Siberian medicinal plants for antimicrobial activity. J Ethnopharmacol. 2002 Sep;82(1):51-3. PMID: 12169406 [PubMed-indexed for MEDLINE].

In this study, the antimicrobial activity of several Siberian plants including tusyllium is investigated. The ethanolic extract of Tussilago farfara was found to possess antimicrobial activity.

Studies on its action at the respiratory level:

Fu JX. Measurement of MEFV in 66 cases of asthma in the convalescent stage and after treatment with Chinese herbs. 1989 Nov;9(11):658-9, 644. PMID: 2611953 [PubMed-indexed for MEDLINE].

         Peak expiratory flow capacity was measured in 66 cases of asthma during the convalescent period and after treatment with Chinese herbs (including Tussilago farfara). After administration of an infusion of Chinese plants to asthmatic patients, it was observed that the measured respiratory parameters improved, suggesting that the airway obstruction in the convalescent state was reversible. The authors indicated that rapid treatment of convalescent asthmatics with Chinese plants, including tusyllium, prevented the development of emphysema.

Li YP, Wang YM. Department of Pharmacology, Shanghai College of Traditional Chinese Medicine. Evaluation of tussilagone: a cardiovascular-respiratory stimulant isolated from Chinese herbal medicine. Gen Pharmacol. 1988;19(2):261-3. PMID: 3350333 [PubMed-indexed for MEDLINE].

       In this study, the cardiorespiratory stimulant capacity of Tussilago farfara was evaluated. Medicinal plants have been used since ancient times in traditional Chinese medicine for the treatment of various respiratory disorders. Recently, tusilago extract has been found to be a potent respiratory and cardiovascular stimulant, having a dopamine-like pressor effect tested in both rats and dogs and cats when administered intravenously to anesthetized animals. A significant stimulation of respiration was also observed, the LD 50 in mice being 28.9 mg/kg.

From a pharmacological point of view, it should be noted that tusilagone, in the dog, is a respiratory stimulant that increases pulmonary ventilation and raises blood pressure (0.02-0.3 mg/kg, i.v.). It has also been shown that this sesquiterpene ketone has an inhibitory activity of PAF-aceter, a meter known to play a role in inflammatory phenomena and respiratory disorders. The possible oral activity of this molecule has not been studied.

Study on its expectorant action:

Muller-Limmroth W, Frohlich HH. Effect of various phytotherapeutic expectorants on mucociliary transport. [Article in German]. Fortschr Med. 1980 Jan 24;98(3):95-101. PMID: 7364365 [PubMed-indexed for MEDLINE].

    In this clinical study, the expectorant action of several plants, among which is the tusilago, was observed. In addition, other effects have been attributed to them as protective of the pharyngeal mucosa, antispasmodic, fluidizing secretions and bactericidal.

Study on their anti-edematous action:

Hwang SB, Chang MN, Garcia ML, Han QQ, Huang L, King VF, Kaczorowski GJ, Winquist RJ. Merck Sharp & Dohme Research Laboratories, Rahway, NJ 07065-0900. L-652,469--a dual receptor antagonist of platelet activating factor and dihydropyridines from Tussilago farfara L. Eur J Pharmacol 1987 Sep 11;141(2):269-81. PMID: 2824219 [PubMed-indexed for MEDLINE].

          In this study it was observed that L652,469 from the chloromethylene extract of Tussilago farfara shoots was able to inhibit both platelet-activating factor and Ca2+ entry blockade by binding to membrane vesicles. It was observed to be effective administered orally with a beneficial effect in inhibiting edema in the rat foot induced by PAF, and the first phase of carrageenan-induced edema in the rat hind paw.

Toxicity studies:

Roulet M, Laurini R, Rivier L, Calame A. Department of Pediatrics, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Switzerland. Hepatic veno-occlusive disease in newborn infant of a woman drinking herbal tea. J Pediatr. 1988 Mar;112(3):433-6. PMID: 3346784 [PubMed-indexed for MEDLINE].

Spang R. Toxicity of tea containing pyrrolizidine alkaloids. J Pediatr. 1989 Dec;115(6):1025. PMID: 2585219 [PubMed-indexed for MEDLINE].

Ridker PM. Hepatic veno-occlusive disease and herbal teas. J Pediatr. 1989 Jul;115(1):167. PMID: 2738787 [PubMed-indexed for MEDLINE].

Sommer M. Hepatic veno-occlusive disease and drinking of herbal teas. J Pediatr. 1989 Oct;115(4):659-60. PMID: 2610755 [PubMed-indexed for MEDLINE].

Study on its chemical composition:

Didry N, Pinkas M, Torck M, Dubreuil L. Components and activity of Tussilago farfara (author's transl). Ann Pharm Fr. 1982 Apr;40(1):75-80. PMID: 7103364 [PubMed-indexed for MEDLINE].

Bibliography

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Bulletin officiel Nº 90/22 bis. Ministère des Affaires Sociales et de la Solidarité.

French Public Health Code.

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