Astragalus

Description and origin

Astragalus (Astragalus membranaceus Moench) belongs to the Leguminosae family and is known as the Huang qi root in China. It is native to China, Mongolia and Sichuan province, and grows in temperate regions.
It is a perennial plant that grows up to 50 cm, with yellow flowers and many branches. It grows on sandy soils in mountain valleys and on riverbanks. It flowers in August and its roots are harvested in autumn (1).

History

Astragalus membranaceus is documented in the Chinese treatise on medicinal plants, Shennong Bencao Jing (200-300 AD) (2). In traditional Chinese medicine, Huang qi is sometimes combined with other plants such as angelica and ginseng in formulas that have been used for centuries in Asia in case of illnesses such as diabetes, heart attacks and kidney disease (3).

Composition

Dried root of astragalus contains polysaccharides, flavonoids, choline, betaine, triterpenoid saponins (astragalosides), amino acids, traces of folic acid and astraisoflavanin (3)

Benefits

Traditional Chinese medicine considers this plant a source of chi (life force) and blood (3). It also has immunostimulant, anti-viral, adaptogenic and vasodilatory properties (4-5).

Studies/research

Astragalus polysaccharides (PSA) have enormous pharmacological potential thanks to their multiple biological functions. Up to 24 polysaccharides have been identified and isolated in Astragalus membranaceus roots. These have various functions (2): immunostimulant, anti-viral, anti-inflammatory, antioxidant, antidiabetic, hepatoprotective, antiatherosclerotic and neuroprotective.
Its immunoregulatory function has been studied both in vivo and in vitro. PSA produce an increase in the number of lymphocytes and gene expression of interleukin-1b and tumour necrosis 𝜶 (both are active in inflammatory reactions and innate immunity), stimulate NK cells, activate macrophages and boost levels of immunoglobulin G and M (3). Together these functions result in increased protection and resistance to illness (2).
PSAs also have exhibit anti-viral activity closely related to the stimulation of the immune system and increased interferon production (protein produced by the immune system that inhibits virus replication) (4-5). They also exhibit antioxidant and anti-inflammatory activity: one study discovered a reduction in the expression of inflammatory mediators induced by the administration of aqueous extract of Astragalus (5).
Finally, Astragalus root has been used in case of rheumatoid arthritis and other autoimmune diseases, and one study discovered a reduction in swelling and arthritic indicators in joints after administration of PSA (2).