Er bestaan allerlei oude gebruiken rondom de maretak: Hij brengt geluk, met kerstmis wordt de plant opgehangen, een kus gegeven onder de maretak versterkt de verbondenheid. In Zweden wordt hij met Sint Jan opgehangen in huis en in de stal om boze geesten en trollen af te weren. De maretak, ofwel Viscum album of vogellijm, groeit in Nederland veelal in Limburg als half-parasiet in bomen, zoals de appelboom, de den, de eik, de populier etc. Er zijn drie ondersoorten: de maretak groeiend op loofbomen, op naaldbomen zoals de den en de maretak groeiend op de spar. Deze zijn botanisch ook verschillend. De naam Viscum betekent kleverigheid, en album duidt op de witte kleur van de bessen. De maretak is een half-parasiet: hij krijgt water en mineralen van de gastheer, maar benut zelf het zonlicht om substantie te vormen. De maretak groeit meestal op zachtere houtsoorten, vooral in de buurt van riviertjes en water.
Wetenschappelijk onderzoek Viscum album
1. H. Becker: "Botany of European Mistletoe (Viscum album L.)" Oncology 43: suppl. 1, pp. 2-7 (1986)
2. E. Jordan, H. Wagner: "Structure and Properties of Polysaccharides from Viscum album (L.)" Oncology 43: suppl. 1, pp. 8-15 (1986)
3. H. Wagner, E. Jordan, B. Feil: "Studies on the Standardization of Mistletoe Preparations" Oncology 43: suppl. 1, pp. 16-22 (1986)
4. Hartmut Franz: "Mistletoe Lectins and Their A and B Chains" Oncology 43: suppl. 1, pp. 23-24 (1986)
5. Gilles Ribereau-Gayon, Marie-Louise Jung, Dominique Di Scala, Jean-Paul Beck: "Comparison of the Effects of Fermented and Unfermented Mistletoe Preparations on Cultured Tumor Cells" Oncology 43: suppl. 1, pp. 35-41 (1986)
6. Tasneen A. Khwaja, Cecilia B. Dias, Stephanie Pentecose: "Recent Studies on the Anticancer Activities of Mistletoe (Viscum album) and Its Alkaloids" Oncology 43: suppl. 1, pp. 42-50 (1986)
7. Hajto, Tibor: "Immunomodulatory Effects of Iscador: A Viscum album Preparation" Oncology 43: suppl. 1, pp. 51-65 (1986)
8. Hajto, Tibor; Oncology 50: pp. 393-398 (1993)
9. Thompson, Lawrence S.: Norse mythology; the Elder Edda in prose translation, 1974.
10. Virgil's Aeneid; translated by Robert Fitzgerald; Vintage Books, 1984
11. Pliny the elder: Natural History; Book XVI
12. Green, Miranda J.: "The World of the Druids" Thames and Hudson, London (1997).
13. http://www.ugcs.caltech.edu/~cherryne/myth.cgi/Introduction.html
14. http://cancernet.nci.nih.gov/cam/mistletoe.htm
15. Grossarth-Maticek R. Kiene H. Baumgartner SM. Ziegler R: "Use of Iscador, an extract of European mistletoe (Viscum album), in cancer treatment"; Alternative Therapies in Health & Medicine. 7(3):57-66, 68-72, 74-6 passim, 2001 May-Jun.
16. Anderson, LA; Phillipson, JD; "Mistletoe‹the Magic Herb"; Pharmaceutical Journal 229: 437-439
17. Stein GM, Schaller G, Pfuller U, Wagner M, Wagner B, Schietzel M, and Bussing A: "Characterisation of granulocyte stimulation by thionins from European mistletoe and from wheat"; Biochimica et Biophysica Acta. 1426(1):80-90, 1999 Jan 4.
18. Edlund U, Hensel A, Frose D, Pfuller U, Scheffler A: "Polysaccharides from fresh Viscum album L. berry extract and their interaction with Viscum album agglutinin I."
19. Romagnoli S. Ugolini R. Fogolari F. Schaller G. Urech K. Giannattasio M. Ragona L. Molinari H.: "NMR structural determination of viscotoxin A3 from Viscum album L."; Biochemical Journal. 350 Pt 2:569-77, 2000 Sep 1.
20. Stein GM. Schaller G. Pfuller U. Schietzel M. Bussing A.: "Thionins from Viscum album L: influence of the viscotoxins on the activation of granulocytes"; Anticancer Research. 19(2A):1037-42, 1999 Mar-Apr.
Voor het maken van antroposofische medicijnen wordt maretak tweemaal per jaar geoogst, namelijk in het voorjaar (het wintersap) en in de herfst (het zomersap). Dat is ook nodig om zowel de lektines als de viscotoxines te benutten. Op een schijf van titanium van een meter doorsnede, die draait met een snelheid van 10.000 toeren per minuut, wordt voortdurend het wintersap op het midden ingegoten, zodat het zich kan verspreiden. Tegelijkertijd wordt het zomersap vanaf een zekere hoogte binnen in de rand gedruppeld. Zo ontstaat een sterker werkend preparaat. Daarna wordt het extract tot verschillende sterktes verdund en in ampullen gedaan. Er wordt een extract van de gehele maretak gebruikt. Het meest bekende maretakpreparaat is Iscador van Weleda. Het wordt in Duitsland zeer vaak toegepast, ook in klinieken.
De Maretak versterkt de activiteit van het immuunsysteem zodat tumorcellen beter worden aangepakt. Het verbetert de doorbloeding, waardoor immuuncellen actiever kunnen worden in het weefsel. Het heeft bovendien een pijn-verzachtende werking, geeft verbetering van de eetlust, verbetering van de slaap, zorgt voor het beter verdragen van de chemotherapie, bestraling en operaties en geeft verbetering van de vitaliteit.
Volgens de antroposofische geneeskunde werkt de maretak met al zijn lichtkwaliteiten tegen het te aards worden, zoals dat bij het kankerproces aan de orde is. Het versterkt de autonomie van de mens en het stimuleert licht en warmtekwaliteiten in de mens. Het is een kosmische plant: hoog in de boom, reagerend op de maanbewegingen en zijn eigen weg gaand, los van de aardse seizoenen. Het kosmische werkt genezend op het ontspoorde, aardse van de kanker.
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| thionines of viscotoxines |
Mistletoe extracts have exhibited both cytotoxic and immunomodulatory properties which have been efficacious in the treatment of cancer. These have been experimentally evaluated in vitro and in vivo. Isolation of lectin and alkaloid compontents of mistletoe extracts have yielded tumor-reducing properties, yet none of these isolated components have been comparable to the effectiveness and relatively low-toxicity of the bulk fermented extract. Constituents of mistletoe with tumor-reducing components include: lectins, viscotoxins, alkaloids, polysaccharides, and polyphenolic substances. Other components include: carbyohydrates, phenolic compounds, sterols, triterpenes, and amines. Factors for testing mistletoe's ability to inhibit the cell-growth of cancerous cells include: type of cell-line, mistletoe species, preparation method (such as fermentation), and the host tree species (due primarily to variable alkaloid content).
The commercial extract Iscador developed in the 1920's has produced the following results in breast cancer patients after one intravenous infusion: enhancement of phagocytic activity of granulocytes (white blood cells); significant increase in natural killer and antibody-dependent cell mediated cytotoxicity; and augmented levels of large granular lymphocytes (white blood cells). The monitored kinetic responses of the immune system with Iscador are similar to those attained after treatment with alpha-ineterferon, which is used to stimulate the immune system in cancer patients. 7 A German study published in 2001 found that Iscador treatment of cancer patients led to prolongation of survival time and stimulation of psychosomatic self-regulation. 15 In vitro studies with Iscador on rat hepatoma tissue culture (HTC) cells and human leukemia Molt 4 cells have yielded cytotoxic effects variable with regard to whether or not a fermented or unfermented extracts were used. Both fermented and unfermented extracts induced rapid lysis of cellular membranes and DNA synthesis inhibition. On Molt 4 cells the fermented extract produces cytolysis after a longer time of action, but the fermented extract is also more potent than unfermented in HTC cell growth inhibition. Unfermented has a stronger cytotoxic effect on Molt 4 than HTC and also has 10 times more lectins. Fermented Iscador was more effective than the well known antitumoral agent 5-fluorouracil (a 5-thymidylate synthase inhibitor) in these tests. 5 The variability due to the fermentation processes is most likely due to the breaking down of toxic lectins.
Three different mistletoe lectins (ML) have been currently isolated. Lectins are proteins or glycoproteins with specific binding sites for sugars which are not antibodies or enzymes. MLI has shown specificity for D-galactose, seems to be the most toxic of the three, and is degraded in fermentation. It is a two-chain conjugate of enzyme and lectin. MLII is D-galactose and N-acetyl D-galactosamine specific. MLIII is N-acetyl D-galactosamine specific. The lectins react with erythrocytes (red blood cells) and immunoglobulins (antibodies) and have experimentally induced cytotoxicity by inhibiting protein synthesis on the ribosomal level. A-chain properties: mitogenicity and inhibition of synthesis in cell-free systems; candidate for construction of immuotoxins. B-chain properties: activate macrophages and release lymphokines from lymphocytes; inhibit allergen-induced histamine release from leukocytes and collagen-induced serotonin release from platelets. Purified lectins produced similar effects to unfermented Iscador extract on both HTC and Molt 4 cells, yet HTC cells are 100 times less sensitive to this than Molt 4 cells. 3,7
Viscotoxins, or thionins, are cytotoxic small molecular weight proteins that inhibit cell growth in vitro at concentrations 100-fold higher than inhibitory lectin concentrations. 8 They have been shown to exhibit stimulatory and cytotoxic effects on immune cells 17, and in a more specific study it was found they exert a strong immunomodulatory effect on human granulocytes (white blood cell type) 20. It has also been postulated that they might be acetylcholine agonists 16.
Polysaccharides in mistletoe play a more ambiguous role as of yet in contrast to the more directly active constituents; they seem function more in association with the lectins and other mistletoe components. In mistletoe berries the sugar complex arabinogalactan is the predominant polysaccharide while in green parts highly esterified galacturonan is more abundant. Although in immunological tests the isolated polysaccharides failed to increase phagocytic activity of granulocytes and macrophages, there is specifc evidence that there are significant interactions between arabinogalactan and galactose-specific lecin (MLI). Therefore, even though mistletoe polysaccharides may not exhibit significant medicinal properties, a synergy may exist between them and other constituents of mistletoe to produce the extract's medicinal effects. 2 Studies on interactions between lectins and polysaccharides found in mistletoe show that agglutination of immune cells by lectins is increased with the presence of mistletoe polysaccharides 18.
Alkaloids are structurally unrelated, basic nitrogenous compounds that possibly act as a plant defense
mechanism against animal and parasitic infection. The alkaloids isolated from California, European, and Korean mistletoe have shown variable degrees of activity, with Korean highest in activity. Isolated alkaloids from Korean mistletoe have produced antitumor effects at relatively high doses with low toxicity and may play contribute to extract cytotoxicity. Alkaloids may exist as glycoconjugates with lectins and/or viscotoxins. It is thought that mistletoe alkaloids are sequestered by the parasite from the host tree. 5
Although the exact nature of mistletoe's historic use cannot be inferred, its centrality in the Aeneid, integral role in Celtic culture, and unique importance in Norse mythology all incur questioning why mistletoe assumed such prominence. Its unique botany no doubt provoked interest in poetic metaphor, yet its Celtic reputation for being a "cure all" contrasted with modern research in mistletoe's bioactivity suggests ancient knowledge of its medicinal properties and its medicinal use to be far more credible and deep than merely primitive or mythological fiction.
Referenties
The commercial extract Iscador developed in the 1920's has produced the following results in breast cancer patients after one intravenous infusion: enhancement of phagocytic activity of granulocytes (white blood cells); significant increase in natural killer and antibody-dependent cell mediated cytotoxicity; and augmented levels of large granular lymphocytes (white blood cells). The monitored kinetic responses of the immune system with Iscador are similar to those attained after treatment with alpha-ineterferon, which is used to stimulate the immune system in cancer patients. 7 A German study published in 2001 found that Iscador treatment of cancer patients led to prolongation of survival time and stimulation of psychosomatic self-regulation. 15 In vitro studies with Iscador on rat hepatoma tissue culture (HTC) cells and human leukemia Molt 4 cells have yielded cytotoxic effects variable with regard to whether or not a fermented or unfermented extracts were used. Both fermented and unfermented extracts induced rapid lysis of cellular membranes and DNA synthesis inhibition. On Molt 4 cells the fermented extract produces cytolysis after a longer time of action, but the fermented extract is also more potent than unfermented in HTC cell growth inhibition. Unfermented has a stronger cytotoxic effect on Molt 4 than HTC and also has 10 times more lectins. Fermented Iscador was more effective than the well known antitumoral agent 5-fluorouracil (a 5-thymidylate synthase inhibitor) in these tests. 5 The variability due to the fermentation processes is most likely due to the breaking down of toxic lectins.
Three different mistletoe lectins (ML) have been currently isolated. Lectins are proteins or glycoproteins with specific binding sites for sugars which are not antibodies or enzymes. MLI has shown specificity for D-galactose, seems to be the most toxic of the three, and is degraded in fermentation. It is a two-chain conjugate of enzyme and lectin. MLII is D-galactose and N-acetyl D-galactosamine specific. MLIII is N-acetyl D-galactosamine specific. The lectins react with erythrocytes (red blood cells) and immunoglobulins (antibodies) and have experimentally induced cytotoxicity by inhibiting protein synthesis on the ribosomal level. A-chain properties: mitogenicity and inhibition of synthesis in cell-free systems; candidate for construction of immuotoxins. B-chain properties: activate macrophages and release lymphokines from lymphocytes; inhibit allergen-induced histamine release from leukocytes and collagen-induced serotonin release from platelets. Purified lectins produced similar effects to unfermented Iscador extract on both HTC and Molt 4 cells, yet HTC cells are 100 times less sensitive to this than Molt 4 cells. 3,7
Viscotoxins, or thionins, are cytotoxic small molecular weight proteins that inhibit cell growth in vitro at concentrations 100-fold higher than inhibitory lectin concentrations. 8 They have been shown to exhibit stimulatory and cytotoxic effects on immune cells 17, and in a more specific study it was found they exert a strong immunomodulatory effect on human granulocytes (white blood cell type) 20. It has also been postulated that they might be acetylcholine agonists 16.
Polysaccharides in mistletoe play a more ambiguous role as of yet in contrast to the more directly active constituents; they seem function more in association with the lectins and other mistletoe components. In mistletoe berries the sugar complex arabinogalactan is the predominant polysaccharide while in green parts highly esterified galacturonan is more abundant. Although in immunological tests the isolated polysaccharides failed to increase phagocytic activity of granulocytes and macrophages, there is specifc evidence that there are significant interactions between arabinogalactan and galactose-specific lecin (MLI). Therefore, even though mistletoe polysaccharides may not exhibit significant medicinal properties, a synergy may exist between them and other constituents of mistletoe to produce the extract's medicinal effects. 2 Studies on interactions between lectins and polysaccharides found in mistletoe show that agglutination of immune cells by lectins is increased with the presence of mistletoe polysaccharides 18.
Alkaloids are structurally unrelated, basic nitrogenous compounds that possibly act as a plant defense
Although the exact nature of mistletoe's historic use cannot be inferred, its centrality in the Aeneid, integral role in Celtic culture, and unique importance in Norse mythology all incur questioning why mistletoe assumed such prominence. Its unique botany no doubt provoked interest in poetic metaphor, yet its Celtic reputation for being a "cure all" contrasted with modern research in mistletoe's bioactivity suggests ancient knowledge of its medicinal properties and its medicinal use to be far more credible and deep than merely primitive or mythological fiction.
Referenties
1. H. Becker: "Botany of European Mistletoe (Viscum album L.)" Oncology 43: suppl. 1, pp. 2-7 (1986)
2. E. Jordan, H. Wagner: "Structure and Properties of Polysaccharides from Viscum album (L.)" Oncology 43: suppl. 1, pp. 8-15 (1986)
3. H. Wagner, E. Jordan, B. Feil: "Studies on the Standardization of Mistletoe Preparations" Oncology 43: suppl. 1, pp. 16-22 (1986)
4. Hartmut Franz: "Mistletoe Lectins and Their A and B Chains" Oncology 43: suppl. 1, pp. 23-24 (1986)
5. Gilles Ribereau-Gayon, Marie-Louise Jung, Dominique Di Scala, Jean-Paul Beck: "Comparison of the Effects of Fermented and Unfermented Mistletoe Preparations on Cultured Tumor Cells" Oncology 43: suppl. 1, pp. 35-41 (1986)
6. Tasneen A. Khwaja, Cecilia B. Dias, Stephanie Pentecose: "Recent Studies on the Anticancer Activities of Mistletoe (Viscum album) and Its Alkaloids" Oncology 43: suppl. 1, pp. 42-50 (1986)
7. Hajto, Tibor: "Immunomodulatory Effects of Iscador: A Viscum album Preparation" Oncology 43: suppl. 1, pp. 51-65 (1986)
8. Hajto, Tibor; Oncology 50: pp. 393-398 (1993)
9. Thompson, Lawrence S.: Norse mythology; the Elder Edda in prose translation, 1974.
10. Virgil's Aeneid; translated by Robert Fitzgerald; Vintage Books, 1984
11. Pliny the elder: Natural History; Book XVI
12. Green, Miranda J.: "The World of the Druids" Thames and Hudson, London (1997).
13. http://www.ugcs.caltech.edu/~cherryne/myth.cgi/Introduction.html
14. http://cancernet.nci.nih.gov/cam/mistletoe.htm
15. Grossarth-Maticek R. Kiene H. Baumgartner SM. Ziegler R: "Use of Iscador, an extract of European mistletoe (Viscum album), in cancer treatment"; Alternative Therapies in Health & Medicine. 7(3):57-66, 68-72, 74-6 passim, 2001 May-Jun.
16. Anderson, LA; Phillipson, JD; "Mistletoe‹the Magic Herb"; Pharmaceutical Journal 229: 437-439
17. Stein GM, Schaller G, Pfuller U, Wagner M, Wagner B, Schietzel M, and Bussing A: "Characterisation of granulocyte stimulation by thionins from European mistletoe and from wheat"; Biochimica et Biophysica Acta. 1426(1):80-90, 1999 Jan 4.
18. Edlund U, Hensel A, Frose D, Pfuller U, Scheffler A: "Polysaccharides from fresh Viscum album L. berry extract and their interaction with Viscum album agglutinin I."
19. Romagnoli S. Ugolini R. Fogolari F. Schaller G. Urech K. Giannattasio M. Ragona L. Molinari H.: "NMR structural determination of viscotoxin A3 from Viscum album L."; Biochemical Journal. 350 Pt 2:569-77, 2000 Sep 1.
20. Stein GM. Schaller G. Pfuller U. Schietzel M. Bussing A.: "Thionins from Viscum album L: influence of the viscotoxins on the activation of granulocytes"; Anticancer Research. 19(2A):1037-42, 1999 Mar-Apr.
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