x uplandicum is said to produce a plant devoid of the toxic alkaloids in the aerial plats, enabling the production of relatively nontoxic comfrey preparations. Stewart 2001 Controlled cultivation of S. The therapeutic use of comfrey is due in part to allantoin and rosmarinic acid content, but it is limited by the toxicity of pyrrolizidine alkaloids. Ahmad 1993, Wagner 1970 Uses and Pharmacology Large amounts of mucilage, fructanes, and starch are found in the leaves and roots Giannetti 2010, Koll 2004 while a pentacyclic triterpene glycoside of oleanolic acid was identified in the root. The roots also contain rosmarinic and lithspermic acid. The underground roots contain allantoin 0.6% to 0.7% and tannin 4% to 6.5% the leaves contain a higher proportion of tannin relative to allantoin. The healing action of poultices of comfrey roots and leaves may be related to the presence of allantoin. Roots contain a 100-fold higher alkaloid content than the aerial portions. Numerous hepatotoxic pyrrolizidine alkaloids with differing toxicities have been identified in the plant, including symphytine, echimidine, intermedine, symviridine, and lasiocarpine (retronecine mono- and diester alkaloids). Staiger 2013, Stewart 2001, Stickel 2000 Chemistry Symphyti radix (comfrey root) is recommended in the German Commission E Monographs for external use in bruises and sprains. Comfrey has been claimed to heal gastric ulcers and hemorrhoids, and to suppress bronchial congestion and inflammation. In Western Europe, comfrey has been used topically for treating inflammatory disorders such as arthritis, gout, and thrombophlebitis, and internally for treating diarrhea. Comfrey's original name, knitbone, derives from the external use of poultices of its leaves and roots to heal burns, sprains, swelling, and bruises. Kucera 2005, PLANTS 2017, Stickel 2000 HistoryĬomfrey has been cultivated in Japan as a green vegetable and has been used as an herbal medicine for more than 2,000 years. asperum, and has been cultivated to contain insignificant amounts of alkaloids in the aerial parts of the plant. It grows to heights of 50 to 150 cm and has long, hairy lanceolate leaves and bell-shaped, red-violet or yellowish flowers. Scientific FamilyĬomfrey is a perennial plant found in moist grasslands in western Asia, as well as in North America. Comfrey is generally considered unsafe, with numerous toxicological effects in animals and humans. The Food and Drug Administration (FDA) released an advisory in July 2001 recommending that comfrey products be removed from the market because of cases of hepatic veno-occlusive disease. Infants are more susceptible to pyrrolizidine-related, veno-occlusive disease therefore, the use of comfrey in this population is contraindicated. Case reports show hepatic veno-occlusive disease and pulmonary hypertension related to comfrey use. Neither internal nor extensive topical use of comfrey is recommended because of numerous reports of liver toxicity (see Toxicology). Animal experiments have detected alkaloids in breast milk. Pyrrolizidine alkaloids have abortifacient effects and increase the risk of fatal hepatic veno-occlusive disease. Pregnancy/LactationĬontraindicated because of documented adverse effects. Use is contraindicated during pregnancy and lactation, in infants, and in patients with liver or kidney disease. Patients with hypersensitivity or allergic reactions to the plant should avoid external use. ContraindicationsĬomfrey is not recommended for internal use because of the hepatotoxic pyrrolizidine alkaloid content. ![]() Limited trials have evaluated the efficacy of alkaloid-free preparations for topical use however, these studies do not report on hepatic laboratory indices of study participants. Additionally, because externally applied alkaloids are well absorbed and detected in the urine, topical use of comfrey should not exceed an alkaloid exposure of 100 mcg/day. Oral use of comfrey is not supported because of potential hepatotoxicity. Although not examined in clinical trials, comfrey may possess antifungal and anticancer activity. A limited number of clinical trials show short-term efficacy of topically applied, alkaloid-free comfrey preparations in skin abrasions and inflammatory conditions. ![]() Therapeutic use of comfrey is limited because of its toxicity. tuberosum L., Symphytum officinale L., Symphytum x uplandicum NymanĬommon Name(s): Blackwort, Bruisewort, Comfrey, Knitbone, Radix consolidate, Russian comfrey, Slippery root, Symphyti radix
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