Wednesday, September 08, 2010

Radix Astragali (Astragalus root) alleviates glucose intolerance, insulin resistance and hypertriglyceridemia

There is a lot of research into various natural substances that can prevent or treat diabetes and its associated metabolic issues. This new one, Radix Astragali appears to be highly effective in reducing inflammation as a pathway to alleviating glucose intolerance, insulin resistance, and hypertriglyceridemia - all common issues in obesity. The article is open source and available as a PDF download (see below).

The effective fraction isolated from Radix Astragali alleviates glucose intolerance, insulin resistance and hypertriglyceridemia in db/db diabetic mice through its anti-inflammatory activity

Ruby LC Hoo email, Janice YL Wong email, Cf Qiao email, Aimin Xu email, Hx Xu email and Karen SL Lam email

Nutrition & Metabolism 2010, 7:67doi:10.1186/1743-7075-7-67

Published: 24 August 2010

Abstract (provisional)

Background

Macrophage infiltration in adipose tissue together with the aberrant production of pro-inflammatory cytokines has been identified as the key link between obesity and its related metabolic disorders. This study aims to isolate bioactive ingredients from the traditional Chinese herb Radix Astragali (Huangqi) that alleviate obesity-induced metabolic damage through inhibiting inflammation.

Methods

Active fraction (Rx) that inhibits pro-inflammatory cytokine production was identified from Radix Astragali by repeated bioactivity-guided high-throughput screening. Major constituents in Rx were identified by column chromatography followed by high-performance liquid chromatography (HPLC) and mass-spectrometry. Anti-diabetic activity of Rx was evaluated in db/db mice.

Results

Treatment with Rx, which included calycosin-7-b-D-glucoside (0.9 %), ononin (1.2%), calycosin (4.53%) and formononetin (1.1 %), significantly reduced the secretion of pro-inflammatory cytokines (TNF-a, IL-6 and MCP-1) in human THP-1 macrophages and lipopolysaccharide (LPS)-induced activation of NF-kB in mouse RAW-Blue macrophages in a dose-dependent manner. Chronic administration of Rx in db/db obese mice markedly decreased the levels of both fed and fasting glucose, reduced serum triglyceride, and also alleviated insulin resistance and glucose intolerance when compared to vehicle-treated controls. The mRNA expression levels of inflammatory cell markers CD68 and F4/80, and cytokines MCP-1 and IL-6 were significantly reduced in epididymal adipose tissue while the alternatively activated macrophage marker arginase I was markedly increased in the Rx-treated mice.

Conclusion

These findings suggest that suppression of the inflammation pathways in macrophages represents a valid strategy for high-throughput screening of lead compounds with anti-diabetic and insulin sensitizing properties, and further support the etiological role of inflammation in the pathogenesis of obesity-related metabolic disorders.

The complete article is available as a provisional PDF. The fully formatted PDF and HTML versions are in production.

Here is some information from a Traditional Chinese Medicine site on this herb, more commonly known as Astragalus root.

Latin Name: Radix Astragali
Common Name: Astragalus root / Milk Vetch root
Scientific Name: Astragalus membranaceus/ Astragalus mongholicus
Chinese Name:黃(耆)
Pinyin Name: Huang qi

Origin
Radix Astragali is the dried root of perennial herbs, Astragalus membranaceus (Fisch.) Bunge and Astragalus mongholicus Bunge (Fabaceae) (1, 2); family Leguminosae.[1]

Where Does It Grow?
It is mainly produced in inner Mongolia, Shanxi, Gansu and Heilongjiang provinces of China.[1]

Nature and Taste
It is sweet, slightly warm in nature and manifests its therapeutic actions in the spleen and lung meridians[1]

Identified Active Components/ Major Chemical Constituents[3]
Primarily, the active constituents of Radix Astragali consist of polysaccharides and flavonoids.[2]

The polysaccharides of Radix Astragali include two glucans, AG-1 (astragalus glucan-1) and AG-2 (astragalus glucan-2), and two heteroglycans, AH-1 (astragalus heteroglycan-1 and AH-2 (astragalus heteroglycan-2). There are other astragalus polysaccharide groups which contain D-glucose, D-galactose, and L-araban. The flavonoid-containing compounds include 7,3-dimercapto-4, 1-methoxyisoflavone, 3-dimercapto-7, 4,1-methoxyisoflavone, catycosin, kumatakenin and fomononetin.

Radix Astragali also contains numerous amino acids, trace elements and various other components, such as astragalus saponin I-II, astragalosides I-IV and soyasapogenoside. Identified amino acids include daucosterol, choline, betaine, folic acid, nicotinamide, and linoleic acid.

Beta-sterol, lupeol, hexanol, palmitic acid, 6-o-beta-D-pyranoglucose, 3-o-beta-D-xylopyranose and carotenol can also be extracted from Astragalus membranaceus (Fisch.) Bge.[26-33]

Historical Use

This herb's Chinese name 'Huang qi' is actually comprised of two Chinese words. The first word "Huang" (黃) means "yellow". Yellow is the color of the herb. Yellow is also the color of the "middle", the "earth" and the "spleen". The second word "Qi" (耆) means "superior" or "senior". The Chinese name of the herb suggests that the herb was considered to be a superior herb used for tonification functions.[4]

1. According to the summary in the Bencao Congxin (New Compilation of Materia Medica): "Radix Astragali is sweet in taste with a warm property. The raw herb can be used to consolidate the exterior of the body. If there is an absence of sweating, it can restore normal sweating, and if there is excessive sweating, it can regulate it to a normal degree. It warms the muscles and strengthens the striae as well as invigorates qi."

The striae are the places where protective qi flows. Protective qi is responsible for protecting the body against the attack of exogenous evils. It can also warm the skin and muscles and regulate the sweating functions. Chinese Medicine places high emphasis on observation of sweating control. Normal sweating control reflects the abundance and good functioning of protective qi. When protective qi is sufficient, sweating will then be under firm and normal control, and the exterior which is the skin and muscles will be considered to be "consolidated". Protective qi is actually governed by the lungs as lungs rule the exterior. Therefore by supporting the lung and protective qi, Radix Astragali can provide good protection against the influence of exogenous evils.

2. Radix Astragali can alleviate heat in the muscles resulting from a qi (vital energy) deficiency.[3] When qi is deficient, the consolidation of the exterior becomes inadequate; and this lets the body's yang-qi wander over the exterior creating heat in the muscles. This is the type of heat manifestation caused by a qi deficiency that Radix Astragali can remove.

3. When the herb is pretreated by broiling, it can invigorate the middle (which is the spleen and stomach) to benefit primordial qi, warm the triple burner and strengthen the spleen and stomach. It can promote the production of blood and muscle growth or regeneration.[3] Qi produces blood. When the blood is sufficient, muscle and tissue can grow or regenerate. 4. Radix Astragali helps drain pus and provide internal (qi) support. It is considered the "sage" herb for abscesses and skin ulcers.[3] Chinese medicine believes that for good healing of abscesses, the toxic qi contained in the abscesses need to be transformed into pus in order to facilitate their evacuation. This process needs internal qi support in order to for this transformation to occur.

5. Radix Astragali can also be used in the treatment of chicken pox or other diseases that manifest with the development of vesicular-papules without adequate"dispersing of the evils."[3] In Chinese Medicine, chicken pox or other diseases that manifest as the development of vesicular-papules are caused by an attack of external evils. For healing chicken pox, the evils need to be “dispersed” through the exterior of the body. This process will lead to further even distribution of the vesicular-papules. This manifestation is considered normal for healing chicken pox. If the vesicular-papules do not develop, it is usually caused by a qi deficiency, and the evils inside the vesicular-papules are considered to be suppressed and trapped inside without proper dispersing. Although symptoms of chicken pox disappear in the end, evils still trapped inside the body can launch an attack in the future when the body is weak. Since Radix Astragali is good at invigorating qi, it supports the normal eruption of vesicular-papules, which assists the healing process for eruptive skin diseases.

It is important to note that Radix Astragali is only suitable for the above conditions, such as abscess, ulcers and skin eruptions, when there is a yang deficiency or qi deficiency without heat symptoms.[3]



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