Astragalus Root Standardized Extract
Also known as: Astragalus root, Huang Qi, Milk Vetch root, Astragalus membranaceus
Overview
Astragalus root extract is derived from the dried root of *Astragalus membranaceus*, a leguminous plant native to China and Mongolia, traditionally used in Traditional Chinese Medicine (TCM) for its immune-enhancing and adaptogenic properties. It is primarily used as an adjunct in chronic diseases, for immune support, anti-aging, cardiovascular health, and as supportive therapy in cancer treatment. The root contains bioactive compounds such as polysaccharides, saponins (astragalosides), and flavonoids. Standardized extracts often focus on astragaloside IV content to ensure consistent potency. Research on Astragalus is moderate, with multiple randomized controlled trials and systematic reviews, primarily from Chinese clinical studies, indicating its potential benefits.
Benefits
Astragalus offers several evidence-based benefits. It acts as an immune modulator and can be used as an adjunct in cancer therapy; a meta-analysis of 19 RCTs showed that Astragalus-containing Chinese herbal medicine combined with chemotherapy improved overall response rates and reduced side effects in cervical cancer patients, though with a high risk of bias. It also exhibits anti-aging and metabolic effects, reducing LDL and total cholesterol, increasing HDL, and improving insulin resistance and diabetic kidney disease markers in preclinical and clinical contexts. Furthermore, Astragalus possesses anti-inflammatory and antioxidant properties by reducing VCAM-1 expression and NF-κB phosphorylation. Secondary benefits include promoting wound healing and skin regeneration in topical applications. These benefits are particularly relevant for cancer patients undergoing chemotherapy, individuals with metabolic syndrome or diabetes, and aging populations. While statistically significant improvements have been reported, the clinical relevance requires further confirmation, and benefits typically manifest over weeks to months.
How it works
Astragalus exerts its effects through several biological pathways. Its immunomodulatory properties are primarily attributed to polysaccharides, which enhance macrophage and lymphocyte function. The anti-inflammatory effects are mediated through the inhibition of the NF-κB pathway, while its antioxidant activity helps combat oxidative stress. Astragalus also modulates lipid metabolism and insulin signaling pathways, contributing to its cardiovascular and metabolic benefits. Molecular targets include VCAM-1, NF-κB, and protein kinase pathways related to insulin resistance. Some components, like formononetin, may interact with estrogen receptors. Astragalosides have moderate bioavailability, and polysaccharides are absorbed, contributing to systemic effects, with bioavailability influenced by extraction methods and co-administered compounds.
Side effects
Astragalus is generally well tolerated, with few serious adverse effects reported in clinical studies. Common, though anecdotal, side effects may include mild fatigue, headache, and hypotension. Uncommon side effects (1-5%) can include possible allergic reactions or gastrointestinal discomfort. Rare serious adverse events have not been conclusively linked to Astragalus alone. However, several drug interactions are notable: Astragalus may antagonize immunosuppressants (e.g., tacrolimus), potentiate anticoagulants, and interact with hormonal therapies due to its estrogenic effects. It may also affect the pharmacokinetics of chemotherapy agents by inhibiting P-glycoprotein. Therefore, caution is advised for patients on immunosuppressants, anticoagulants, or hormonal therapies. Data on use during pregnancy and lactation are limited, so caution is recommended for these special populations.
Dosage
The minimum effective dose of Astragalus varies by extract standardization, with clinical studies often using doses standardized to astragaloside IV content ranging from 20 to 50 mg/day equivalent. Optimal dosage ranges in clinical trials typically involve 30–60 mg/day of astragaloside IV equivalents or corresponding extract doses, depending on the specific formulation and indication. The maximum safe dose is not well established, but doses used in trials are generally well tolerated. Astragalus is often administered daily, and the timing relative to meals is not considered critical, though it may influence absorption. Standardized extracts are preferred for consistent bioactive content, while polysaccharide-rich extracts are used for immune effects. Co-administration with other compounds, such as ferulic acid, may enhance its effects. No specific cofactors are required for its efficacy.
FAQs
Is Astragalus safe to use with chemotherapy?
Evidence suggests it may improve efficacy and reduce side effects, but it should only be used under medical supervision due to potential drug interactions.
How long before benefits appear?
Clinical improvements are often observed after several weeks of consistent daily use, depending on the condition and formulation.
Can it lower blood pressure?
Yes, mild hypotensive effects have been reported with Astragalus use, which may be a consideration for individuals with low blood pressure.
Does it interact with immunosuppressants?
Yes, Astragalus may reduce the effectiveness of immunosuppressant medications, so concurrent use should be avoided or closely monitored by a healthcare professional.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC11885490/ – This systematic review and meta-analysis of multiple RCTs found that Astragalus adjunct therapy improved disease activity scores and renal function markers in SLE patients. However, the study noted heterogeneity in herbal formulas and a moderate risk of bias, suggesting the need for more standardized research.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC12029721/ – This narrative review synthesized preclinical and clinical data, indicating that Astragalus can reduce cholesterol, improve insulin resistance, and exert anti-inflammatory effects. While comprehensive, it highlighted that much of the evidence is preclinical, with a limited number of large-scale randomized controlled trials.
- https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2021.587021/full – This systematic review and meta-analysis of 19 RCTs involving 1649 cervical cancer patients found that Astragalus-containing Chinese herbal medicine combined with chemotherapy improved response rates and reduced side effects. Despite promising results, the study noted a high risk of bias due to lack of blinding and that all included studies were from China.
- https://www.mskcc.org/cancer-care/integrative-medicine/herbs/astragalus – This resource from Memorial Sloan Kettering Cancer Center provides an overview of Astragalus, including its traditional uses, potential benefits, and important safety considerations such as drug interactions, particularly with immunosuppressants and hormonal therapies. It serves as a reliable source for patient and clinician information.
- https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2024.1362550/full – This article discusses the various bioactive compounds in Astragalus, such as astragalosides and polysaccharides, and their roles in immunomodulation, anti-inflammatory, and antioxidant activities. It delves into the molecular mechanisms by which Astragalus exerts its therapeutic effects, including its impact on metabolic pathways and cellular signaling.
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