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Petasites hyperboreus |
Petasites hyperboreus |
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Agosti R., R. K. Duke, J. E. Chrubasik and S. Chrubasik. 2006. Effectiveness of Petasites hybridus preparations in the prophylaxis of migraine: A systematic review. Phytomedicine 13(9-10): 743–746. “The objective of this review was to evaluate the strength of evidence of effectiveness for Petasites hybridus in the prophylaxis of migraine. Several databases and other sources were searched to identify randomised-controlled trials investigating P. hybridus preparations. Two trials totalling 293 patients (60 and 233 patients) were included in this review. Both trials investigated the proprietary Petasites root extract Petadolex((R)). The trials were described in narrative way, taking into consideration methodological quality scores. Pooling of data was not carried out due to the heterogeneity of the results. The extract at higher dose (150mg) showed a greater decreased frequency of migraine attacks and a greater number of responders (improvement >50%) after treatment over 3-4 months than the extract at lower dose (100mg) and placebo. Moderate evidence of effectiveness is, thus, available for a higher than the recommended dose of the proprietary Petasites root extract Petadolex((R)) in the prophylaxis of migraine. Further rigorous studies are required to confirm effectiveness and safety in long-term use before treatment with Petasites root extract can be recommended as an alternative option in the treatment schedule for the prophylaxis of migraine.” Bickel D., T. Roder, H. J. Bestmann and K. Brune. 1994. Identification and characterization of inhibitors of peptido-leukotriene-synthesis from Petasites hybridus. Planta Med. 60(4): 318–322. “Extracts from Petasites hybridus were found to inhibit peptido-leukotriene biosynthesis in isolated peritoneal macrophages. Chemical analysis by gas chromatography coupled with mass and infrared spectroscopy facilitated the identification of three isomeric oxopetasan esters, petasin, and isopetasin as the main compounds of these extracts. Fractionations obtained by column chromatography of the most effective extract indicated a correlation between peptido-leukotriene biosynthesis inhibition and the content of isopetasin, a sesquiterpene ester of isopetasol and angelic acid, as well as the isomeric oxopetasan esters. Petasin, a structural isomer of isopetasin, however, was found to be inactive. It may even reduce the peptido-leukotrine inhibitory effect of isopetasin. It is concluded that isopetasin and the oxopetasan esters in Petasites hybridus inhibit the biosynthesis of the vasoconstrictive peptido-leukotrienes. This effect may contribute to some of the medicinal properties of Petasites hybridus extracts such as, e.g., gastroprotection and spasmolytic activity.” Chizzola, R. 1991. Variability in toxic pyrrolizidine alkaloid content of Petasites hybridus. American Society of Pharmacognosy 32nd Annual Meeting, poster, abstract (P66), University of Illinois at Chicago, July 21–26. Petasites hybridus, butter bur, is a perennial plant wiht large leaves and thick rhizomes growing on riversides and other wet habitats throughout central Europe. From t the two known chemotypes, the one containing sesquiterpeneesters, is used pharmaceutically for its spasmolytic properties. Besides these useful compounds, this plant contains trace amounts of highly toxic pyrrolizidine alkaloids, mainly the macrocylcic diesters senecionine, integerrimine and senkirkine. Because of their possible carcinogenic and mutagenic effects, the Federal Health Office (Bundesgesundheitsamt) of Germany suggests to withdraw plants or plant extracts containing more than 0.1 ppm of such alkaloids. In order to search for alkaloid free, or alkaloid poor individuals or populations, we investigated the variability in concentration of these three main alkaloids. The plants were taken from different natural habitats throughout Austria. A new rapid and solvent saving clean up procedure for plant extracts using columns packed with an oxygen absorber resin and strong cation exchange resins was developed. The obtained alkaloid fractions were suitable for GC and TLC analysis. The levels of senecionine, the main alkaloid, ranged from less than 5 ppm to more than 250 ppm in dried rhizome. Plants of the useful chemotype, poor in alkaloids, may be found in the Tyrol, Vorarlberg and Bavaria. Individuals completely free of alkaloids could not be detected. Goto Y., Y. Kojima, T. Nakayama and M. Terazawa. 2001. Allelopathic sesquiterpenoids from rhizomes of Petasites japonicus ssp. giganteus Kitam. Phytochemistry 57(1): 109–113. “Four sesquiterpenoids were isolated from Petasites japonicus (Siebold and Zucc.) Maxim. ssp. giganteus (F. Schmidt ex Trautv.) Kitam. (Compositae, Japanese name: Akitabuki) as allelochemicals. Their structures were elucidated on the basis of spectroscopic methods and their allelopathic effects were assessed.” Hauser S.P. Alzoon--antineoplastic remedy or medicinal syrup? 1997. Schweiz. Rundsch. Med. Prax. 86(27-28): 1113–1115. “Alzoon is a concoction containing extracts of petasites, juniper, ferns, brunellias, and dandelions that has been treated with oxygen and UV-light. A variety of indications are claimed: cachexia, severe pain, anemia as a result of malignant tumors, stomach or duodenal ulcers and also relief for desperate end-stage cancer patients. A long-term treatment is recommended. Prior to meals 2 to 3 times daily, 1-2 tablespoons of Alzoon are recommended. A bottle with 1 liter costs CHF 31.80. Apparently, Alzoon is harmless and free of side effects. Alzoon was patented in 1943 by the chemist M. R. von Niederhausern from Basel. His company Alsana Inc. (pharmaceutical specialities, Thun, Switzerland) produces and sells Alzoon. A mechanism of action is not mentioned. Alzoon is sold as "holistic therapy", and is supposed to relieve pain, stimulate appetite, and enhance quality of life. The most important plant of the mixture is supposedly petasites. In the mid sixties a study on 42 patients was conducted under the pressure of the Alsana Inc. and v. Niederhausern. The analysis of the results of the two experts showed that Alzoon had no influence on tumor growth. Six patients (14%) had a temporary improvement of quality of life and appetite. Further trials do not exist. In Switzerland, Alzoon is registered on the list D at the IKS, but is not reimbursable by insurance companies. It is not established as an anti-cancer remedy.” Hirono I., H. Mori, K. Yamada, Y. Hirata and M. Haga. 1977. Carcinogenic activity of petasitenine, a new pyrrolizidine alkaloid isolated from Petasites japonicus Maxim. J. Natl. Cancer Inst. 58(4): 1155–1157. “The carcinogenic activity of petasitenine, a new pyrrolizidine alkaloid isolated from young flower stalk of Petasites japonicus, was studied in ACI rats. All rats that had received a 0.05% solution of petasitenine in drinking water died or were killed in moribund condition 72 days after the start of experiment. They showed necrosis, hemorrhage, and remarkable proliferation of the bile ducts in the liver. In another group that had received a 0.01% solution, 8 of 10 animals surviving beyond 160 days developed tumors in the liver, i.e., hemangioendothelial sarcomas in 5 rats and liver cell adenomas in 5 rats, 2 of which simultaneously developed hemangioendothelial sarcomas. No tumors were observed in the livers of the control animals.” Iriye R., K. Furukawa, R. Nishida, C. Kim and H. Fukami. 1992. Isolation and synthesis of a new bio-antimutagen, petasiphenol, from scapes of Petasites japonicum. Biosci. Biotechnol. Biochem. 56(11): 1773–1775. “A new bio-antimutagen, petasiphenol [3-(3,4-dihydroxyphenyl)-2-oxopropyl caffeate] (1) was isolated from scapes of Petasites japonicum (AD50 = 95 micrograms/ml against UV-induced mutagenic E. coli WP2 B/r Trp-. Petasiphenol (1) and its isomer (2) were synthesized. The activity of 1 was observed in the presence of soybean oil (glyceride), although the isomer (2) did not show any activity in doses up to 300 micrograms/ml.” Liao C. H., F. N. Ko, T. S. Wu and C. M. Teng CM. 1997. Bakkenolide G, a natural PAF-receptor antagonist. J. Pharm. Pharmacol. 49(12): 1248–1253. “Because platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) participates in many physiopathological responses, including inflammatory reaction, endotoxic shock, allergic diseases and platelet aggregation, PAF-receptor antagonists are important in the treatment of these diseases. A biologically active compound, bakkenolide G, extracted from the plant Petasites formosanus selectively and concentration-dependently inhibited PAF-induced platelet aggregation and ATP release. The IC50 of bakkenolide G for PAF (2 ng mL(-1))-induced platelet aggregation was 5.6 +/- 0.9 microM. Bakkenolide G also concentration-dependently inhibited PAF-induced intracellular signal transductions, including thromboxane B2 formation, and increased intra-cellular calcium concentration and phosphoinositide breakdown without affecting those caused by thrombin (0.1 units mL(-1)), collagen (10 microg mL(-1)), arachidonic acid (100 microM) and U46619 (1 microM). Bakkenolide G shifted the concentration-response curves of PAF-induced platelet aggregation parallel to the right; the Schild plot slope and the pA2 value were 1.31 +/- 0.31 and 6.21 +/- 0.75, respectively. Moreover, bakkenolide G concentration-dependently competed with [3H]PAF binding to platelets, with an IC50 value of 2.5 +/- 0.4 microM. These data strongly indicate that bakkenolide G is a specific PAF-receptor antagonist as an antiplatelet aggregatory agent.” Wu T. S., M. S. Kao, P. L. Wu, F. W. Lin, L. S. Shi, M. J. Liou and C. Y. Li. 1999. The bakkenolides from the root of Petasites formosanus and their cytotoxicity. Chem. Pharm. Bull. (Tokyo) 47(3): 375–382. “Thirty-two new bakkenolides, bakkenolides-Db (1)--Dh(7), -Fa(8), -Fb(9), -I(10)--M(14), -Na(15), -Nb(16), -O(17)--T(22), -Ua (23), -Ub(24), -V(25)--X(27), -Ya(28), -Yb(29), -Za(30), -Zb(31) and -III(32), from the roots of Petasites formosanus together with thirty known compounds were isolated. The structures were characterized by spectral analysis. The locations, C-1 and/or C-9 of bakkenolide skeleton, of the substituents, such as acetoxy, isobutyroyloxy and isovaleroyloxy groups, can be determined by the chemical shifts of their signals and the H-1 and/H-9 in the 1H-NMR spectra. The cytotoxicity was also discussed.” |
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