Astragalus

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Astragalus
Astragalus tragacantha ssp. vicentinus
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Fabales
Family: Fabaceae
Subfamily: Faboideae
Tribe: Galegeae
Subtribe: Astragalinae
Genus: Astragalus
L.
Type species
Astragalus onobrychis
L.
Synonyms

Acanthophaca Nevski
Aragallus Neck. ex Greene
Astenolobium Nevski
Astracantha Podlech
Atelophragma Rydb.
Barnebyella Podlech
Batidophaca Rydb.
Biserrula L.[Note 1]
Brachyphragma Rydb.
Cnemidophacos Rydb.
Contortuplicata Medik.
Cryptorrhynchus Nevski
Ctenophyllum Rydb.
Cystium Steven
Didymopelta Regel & Schmalh.
Diholcos Rydb.
Diplotheca Hochst.
Erophaca Boiss.[Note 1]
Geoprumnon Rydb.
Gynophoraria Rydb.
Hamosa Medik.
Hedyphylla Steven
Hesperastragalus A. Heller
Hesperonix Rydb.
Holcophacos Rydb.
Homalobus Nutt.
Jonesiella Rydb.
Kentrophyta Nutt.
Kiapasia Woronow ex Grossh.
Lonchophaca Rydb.
Microphacos Rydb.
Mystirophora Nevski
Neodielsia Harms
Oedicephalus Nevski
Onix Medik.
Ophiocarpus (Bunge) Ikonn.
Orophaca (Torr. & A. Gray) Britton[Note 1]
Oxyglottis (Bunge) Nevski
Phaca L.
Phacomene Rydb.
Phacopsis Rydb.
Phyllolobium Fisch. ex Spreng.[Note 1]
Pisophaca Rydb.
Podlechiella Maassoumi & Kaz. Osaloo[Note 1]
Poecilocarpus Nevski
Pterophacos Rydb.
Sewerzowia Regel & Schmalh.
Thium Steud.
Tragacantha Mill.
Xylophacos Rydb.

Astragalus is a large genus of about 3,000 species[1] of herbs and small shrubs, belonging to the legume family Fabaceae and the subfamily Faboideae. The genus is native to temperate regions of the Northern Hemisphere. Common names include milkvetch (most species), locoweed (in North America, some species)[2] and goat's-thorn (A. gummifer, A. tragacanthus). Some pale-flowered vetches are similar in appearance, but vetches are more vine-like.

Ecology[edit]

Astragalus species are used as food plants by the larvae of some Lepidoptera species including many case-bearing moths of the genus Coleophora: C. cartilaginella, C. colutella, C. euryaula, and C. onobrychiella feed exclusively on Astragalus, C. astragalella and C. gallipennella feed exclusively on the species Astragalus glycyphyllos, and C. hippodromica is limited to Astragalus gombo.

Traditional uses[edit]

The natural gum tragacanth is made from several species of Astragalus occurring in the Middle East, including A. adscendens, A. gummifer, A. brachycalyx,[3][4] and A. tragacanthus. Also Astragalus propinquus (syn. A. membranaceus) has a history of use as a herbal medicine used in systems of traditional Chinese medicine.[5] and Persian medicine [6]

Research[edit]

Biotechnology firms are working on deriving a telomerase activator from Astragalus. The chemical constituent cycloastragenol (also called TAT2) is being studied to help combat HIV, as well as infections associated with chronic diseases or aging.[7] However, the National Institutes of Health states: "The evidence for using astragalus for any health condition is limited. High-quality clinical trials (studies in people) are generally lacking. There is some preliminary evidence to suggest that astragalus, either alone or in combination with other herbs, may have potential benefits for the immune system, heart, and liver, and as an adjunctive therapy for cancer".[8]

Research at the UCLA AIDS Institute focused on the function of cycloastragenol in the aging process of immune cells, and its effects on the cells' response to viral infections. It appears to increase the production of telomerase, an enzyme that mediates the replacement of short bits of DNA known as telomeres, which play a key role in cell replication, including in cancer processes.[9]

Supplement use[edit]

Extracts of Astragalus propinquus ( syn. A. membranaceus) are marketed as life-prolonging extracts for human use. A proprietary extract of the dried root of A. membranaceus, called TA-65, "was associated with a significant age-reversal effect in the immune system, in that it led to declines in the percentage of senescent cytotoxic T cells and natural killer cells after six to twelve months of use".[10] There are mixed data regarding Astragalus, its effects on telomerase, and cancer. For example while 80% of cancer cells utilize telomerase for their proliferation - a factor which might theoretically be exacerbated by Astragalus - the shortening of telomeres (resulting from such factors as stress and aging and possible contributors to malignancy), might also be mitigated by Astragalus. Thus, short telomeres result in chromosome instability, and the potential for telomere lengthening as a protection against cancer is possible.[11] Additionally, scientists recently reported in Molecular and Cellular Biology that cancer cells may proliferate precisely because of the lack of differentiation occurring via damaged or shortened telomere length. They propose that "forced" elongation of telomeres promotes the differentiation of cancer cells, probably reducing malignancy, which is strongly associated with a loss of cell differentiation.

Side effects and toxicology[edit]

Astragalus may interact with medications that suppress the immune system, such as cyclophosphamide.[8] It may also affect blood sugar levels and blood pressure.[8] Some Astragalus species can be toxic. For example, several species native to North America contain the neurotoxin swainsonine.[8] The toxicity of Astragalus taxa varies.[12]

Ornamental use[edit]

Several species, including A. alpinus (bluish-purple flowers), A. hypoglottis (purple flowers), and A. lotoides, are grown as ornamental plants in gardens.

Selected species[edit]

See also[edit]

Notes[edit]

  1. ^ a b c d e This may actually be a valid genus.

References[edit]

  1. ^ Frodin, D. G. (2004). "History and concepts of big plant genera". Taxon 53 (3): 753–776. doi:10.2307/4135449. 
  2. ^ "Astragalus (Locoweed) flowers". Rootcellar.us. Retrieved 2013-07-05. 
  3. ^ [1][dead link]
  4. ^ "Astragalus brachycalyx Fisch.". Germplasm Resources Information Network (GRIN) online database. Retrieved 24 December 2010. 
  5. ^ "Astragalus | University of Maryland Medical Center". Umm.edu. 2013-05-07. Retrieved 2013-07-05. 
  6. ^ Zargary, A. Medicinal plants. 5th Edition.Tehran: Tehran University Publications 1990; pp. 312-314
  7. ^ "Herbal chemical helps combat HIV". United Press International. January 1, 2009. Retrieved January 28, 2011. 
  8. ^ a b c d Astragalus, NCCAM
  9. ^ Fauce, S. R., et al. (2008). "Telomerase-Based Pharmacologic Enhancement of Antiviral Function of Human CD8+ T Lymphocytes". Journal of Immunology 181 (10): 7400–7406. PMC 2682219. PMID 18981163. Retrieved 2012-08-18. 
  10. ^ Harley, C. B., et al. (2011). "A natural product telomerase activator as part of a health maintenance program". Rejuvenation Research 14 (1): 45–56. doi:10.1089/rej.2010.1085. PMC 3045570. PMID 20822369. 
  11. ^ Hiyama, K., et al. (2009). "Role of telomeres and telomerase in cancer". In K. Hiyama. Telomeres and Telomerase in Cancer. Cancer Drug Discovery and Development II. Humana Press. pp. 171–180. doi:10.1007/978-1-60327-879-9_7. ISBN 978-1-60327-879-9. 
  12. ^ Rios, J. L.; P. G. Waterman (1998). "A review of the pharmacology and toxicology of Astragalus". Phytotherapy Research 11 (6): 411–418. doi:10.1002/(SICI)1099-1573(199709)11:6<411::AID-PTR132>3.0.CO;2-6. 

External links[edit]