Articles

Larch Arabinogalactan

Plant Part Used

Bark extract

Active Constituents

Arabinogalactan (3,6-beta-D-galactan type polysaccharide).[147" /] [span class=alert]

This section is a list of chemical entities identified in this dietary supplement to possess pharmacological activity. This list does not imply that other, yet unidentified, constituents do not influence the pharmacological activity of this dietary supplement nor does it imply that any one constituent possesses greater influence on the overall pharmacological effect of this dietary supplement.[/span]

Introduction

Arabinogalactans are a class of long, densely branched polysaccharides of the 3,6-beta-D-galactan type with molecular weights ranging from 10,000-120,000. (1) These polysaccharides are found in a wide range of foods, including carrots, radishes, pears, corn, wheat, red wine, tomatoes, coconut meat, and also in medicinal herbs such as echinacea, wild indigo, cedar leaf, and turmeric among others. (2) , (3) Arabinogalactan is also quite abundant in plants of the genus Larix and has a wide range of food and dietary supplement uses.

The primary source of arabinogalactan in the food and supplement industry is the larch tree (Larix sp.), with the larch arabinogalactan extracted by counter current technology from either of two sources: western larch (Larix occidentalis) or Mongolian larch (Larix dahurica). At this time in the United States, all commercially available larch arabinogalactan (LA) is produced from the western larch. This LA is FDA approved for food applications, including: emulsifier, stabilizer, binder or bodying agent in essential oils, non-nutritive sweetener, and in various flavor bases among other uses.

Because of the immune-enhancing properties, LA is receiving increased attention as a clinically useful immunomodulating agent. (4) LA may be a good therapeutic choice for individuals with chronic immune system disturbances such as colds and influenza, chronic fatigue, and viral hepatitis among others. LA has been used with success in children, specifically in otitis media. (5)

Interactions and Depletions

Interactions

Dosage Info

Dosage Range

400mg, 1-2 capsules 3-4 times a day.

Powder: Mix 1/2-2 tablespoonsful in favorite beverage and take up to 3-4 times a day.

Adjust dosage for children based on body weight.

Dosage should be taken for 7-10 days for acute problems. For chronic problems with immunity, take on a 3 weeks on, 1 week off schedule.

Most Common Dosage

400mg, 4 times a day.

Powder: ½ tablespoonful in beverage, 4 times a day.

Adjust dosage for children based on body weight.

Dosage should be taken for 7-10 days for acute problems. For chronic problems with immunity, take on a 3 weeks on, 1 week off schedule.

Standardization

[span class=doc]Standardization represents the complete body of information and controls that serve to enhance the batch to batch consistency of a botanical product, including but not limited to the presence of a marker compound at a defined level or within a defined range.[/span]

The most current available medical and scientific literature indicates that this dietary supplement should be standardized to at least 98-percent arabinogalactan.

Uses

Frequently Reported Uses

  • Influenza
  • Colds
  • Adjunctive Support In Chemotherapy And Radiation
  • Bacterial Infections
  • Potential Benefit In Cancer Prevention And Support

Other Reported Uses

  • Candida
  • Allergies
  • Immune Enhancement

 

Toxicities & Precautions

General

Larch arabinogalactan (LA) is reported safe in recommended dosages and is FDA approved for a variety of food uses and applications. LA was reported less toxic than methylcellulose in laboratory studies. (6)

Pharmacology

Arabinogalactan is an excellent source of dietary fiber; is approved as a dietary fiber by the FDA; has been reported to increase the production of short-chain fatty acids (SCFAs), principally butyrate and propionate; and has been reported to decrease the generation and absorption of ammonia, thereby potentially improving colon health. (7) , (8) LA may promote an increase in bifidobacteria, particularly Bifidobacterium longum, which appears to have the most specificity to ferment arabinogalactan. (9) Unpublished evidence following a controlled study of larch arabinogalactan supplementation in human volunteers has similarly demonstrated an ability to promote an increase of bifidobacteria, as well as other anaerobes such as lactobacillus. (10) This may be a significant benefit in disturbances of the GI bacterial flora due to prescribed antibiotics or other causes. (11)

LA is reported to enhance immunity by various methods. Studies report that LA stimulates natural killer cell cytotoxicity, enhances other functional aspects of the immune system, and inhibits the metastasis of tumor cells to the liver. (12) These actions may have utility as components to support conventional therapies such as cancer treatment and HIV infection.

Natural Killer (NK) Cytotoxicity: It has been reported that decreased NK cell activity may be linked to a variety of chronic diseases including cancer, (13) chronic fatigue syndrome (CFS), (14) , (15) prostate cancer, autoimmune diseases such as multiple sclerosis, (16) and viral hepatitis. (17) Investigators report that LA stimulated NK cell cytotoxicity against a tumor cell line in vitro. (18) The larch arabinogalactan-mediated enhancement of NK cytotoxicity does not appear to be initiated directly, but may be governed by the cytokine network. Generally, LA pretreatment induces an increased release of interferon gamma, tumor necrosis factor alpha, interleukin-1 beta, and interleukin-6. Results suggest the increase in interferon gamma was most responsible for the observed enhancement of NK cytotoxicity.

Reticuloendothelial and Complement Activation: Low to middle molecular weight (5,000-50,000) arabinogalactan polysaccharides isolated from larch and non-larch sources have been reported to have immunostimulating properties, including the ability to activate phagocytosis and potentiate reticuloendothelial system activity. (19) , (20) Several arabinogalactans (isolated from non-larch sources) have also been reported to have anti-complement activity. (21)

Anti-metastatic Activity: Metastatic disease may spread to the liver in many cases. This is based on a theory of a reaction between the galactose-based glycoconjugate on the metastatic cells and hepatic-specific lectin-like receptors (e.g., the D-galactose-specific hepatic binding protein) found in liver parenchyma. Several studies have reported that larch arabinogalactan may alter this reaction by inhibiting the attachment of metastatic cells to liver parenchyma via competitive binding to liver hepatic galactose receptors. In addition, arabinogalactan reportedly provides immune system enhancement and support. (22)

A study involving animals with liver carcinoma treated with arabinogalactan reported a reduced amount of liver metastasis and also had prolonged survival times, although all test animals eventually succumbed to liver metastasis. The reported mechanism of slowing metastasis was the effect of arabinogalactan's blockade of potential liver receptors by covering galactose-specific binding sites. (23) Similar results were also demonstrated in an earlier study. (24)

In another laboratory study, arabinogalactan as a receptor-blocking agent completely prevented the damaging effects of metastatic sarcoma L-1 tumor cells in the liver of experimental animals. (25) The same lead author repeated these results in a subsequent laboratory animal study that also demonstrated arabinogalactan greatly reduced the colonization process of highly metastatic lymphoma cells. (26)

References

  1. Odonmazig P, Ebringerova A, Machova E, et al. Structural and Molecular Properties of the Arabinogalactan Isolated from Mongolian Larchwood (Larix dahurica L.). Carbohydr Res. Jan1994;252:317-24.
  2. View Abstract: Gonda R, et al. Arabinogalactan Core Structure and Immunological Activities of Ukonan C, An Acidic Polysaccharide from the Rhizome of Curcuma longa. Biol Pharm Bull. 1993;16:235-238.
  3. View Abstract: Egert D, et al. Studies on Antigen Specificity of Immunoreactive Arabinogalactan Proteins Extracted from Baptisia tinctoria and Echinacea purpurea. Planta Med. 1992;58:163-165.
  4. View Abstract: Hauer J, et al. Mechanism of Stimulation of Human Natural Killer Cytotoxicity by Arabinogalactan from Larix occidentalis. Cancer Immunol Immunother. 1993;36(4):237-44.
  5. View Abstract: Kelly G. Larch Arabinogalactan: Clinical Relevance of a Novel Immune-Enhancing Polysaccharide. Altern Med Rev. 1999;4(2):96-103.
  6. View Abstract: Groman EV, et al. Arabinogalactan for Hepatic Drug Delivery. Bioconjug Chem. 1994;5:547-556.
  7. View Abstract: Vince AJ, et al. The Effect of Lactulose, Pectin, Arabinogalactan and Cellulose on the Production of Organic Acids and Metabolism of Ammonia by Intestinal Bacteria in a Faecal Incubation System. Br J Nutr. Jan1990;63(1):17-26.
  8. Tsao D, et al. Effect of Sodium Butyrate on Carcinoembryonic Antigen Production by Human Colonic Adenocarcinoma Cells in Culture. Cancer Res. 1983;43:1217-1222.
  9. View Abstract: Crociani F, et al. Degradation of Complex Carbohydrates by Bifidobacterium spp. Int J Food Microbiol. 1994;24:199-210.
  10. View Abstract: Kelly G. Larch Arabinogalactan: Clinical Relevance of a Novel Immune-Enhancing Polysaccharide. Altern Med Rev. 1999;4(2):96-103.
  11. View Abstract: Rolfe RD. The Role of Probiotic Cultures in the Control of Gastrointestinal Health. J Nutr. Feb2000;130(2S Suppl):396S-402S.
  12. View Abstract: Hauer J, et al. Mechanism of Stimulation of Human Natural Killer Cytotoxicity by Arabinogalactan from Larix occidentalis. Cancer Immunol Immunother. 1993;36:237-244.
  13. View Abstract: Parra S, Pinochet R, Vargas R, et al. Natural killer cytolytic activity in renal and prostatic cancer. Rev Med Chil. 1994;122:630-637.
  14. View Abstract: Levine PH, et al. Dysfunction of Natural Killer Activity in a Family With Chronic Fatigue Syndrome. Clin Immunol Immunopathol. 1998;88:96-104.
  15. View Abstract: Uchida A. Therapy of Chronic Fatigue Syndrome. Nippon Rinsho. 1992;50:2679-2683.
  16. View Abstract: Kastrukoff LF, et al. A Role for Natural Killer Cells in the Immunopathogenesis of Multiple Sclerosis. J Neuroimmunol. 1998;86:123-133.
  17. View Abstract: Corado J, et al. Impairment of Natural Killer (NK) Cytotoxic Activity in Hepatitis C Virus (HCV) Infection. Exp Immunol. 1997;109:451-457.
  18. View Abstract: Hauer J, et al. Mechanism of Stimulation of Human Natural Killer Cytotoxicity by Arabinogalactan from Larix occidentalis. Cancer Immunol Immunother. 1993;36:237-244.
  19. View Abstract: Gonda R, et al. Arabinogalactan Core Structure and Immunological Activities of Ukonan C, An Acidic Polysaccharide from the Rhizome of Curcuma longa. Biol Pharm Bull. 1993;16:235-238.
  20. View Abstract: Egert D, et al. Studies on Antigen Specificity of Immunoreactive Arabinogalactan Proteins Extracted from Baptisia tinctoria and Echinacea purpurea. Planta Med. 1992;58:163-165.
  21. View Abstract: Kiyohara H, et al. Relationship Between Structure and Activity of An Anti-complementary Arabinogalactan from the Roots of Angelica acutiloba Kitagawa. Carbohydr Res. 1989;193:173-192.
  22. View Abstract: Kelly G. Larch Arabinogalactan: Clinical Relevance of a Novel Immune-Enhancing Polysaccharide. Altern Med Rev. 1999;4(2):96-103.
  23. View Abstract: Hagmar B, et al. Arabinogalactan Blockade of Experimental Metastases to Liver by Murine Hepatoma. Invasion Metastasis. 1991;11:348-355.
  24. Uhlenbruck G, et al. Prevention of Experimental Liver Metastases by Arabinogalactan. Naturwissenschaften. 1986;73:626-627.
  25. View Abstract: Beuth J, et al. Inhibition of Liver Metastasis in Mice by Blocking Hepatocyte Lectins with Arabinogalactan Infusions and D-galactose. J Cancer Res Clin Oncol. 1987;113:51-55.
  26. View Abstract: Beuth J, et al. Inhibition of Liver Tumor Cell Colonization in Two Animal Tumor Models by Lectin Blocking with D-galactose or Arabinogalactan. Clin Exp Metastasis. 1988;6:115-120.