Herbal Medicine Monograph: Astragalus Membranaceus Essay Example

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Herbal Medicine Monograph: Astragalus Membranaceus

Herbal Medicine Monograph: Astragalus membranaceus

Geographical, Taxonomic, and Morphological Characteristics of Astragalus membranaceus

Astragalus membranaceus is an important and popular drug used in Traditional Chinese Medicine (TCM) with attribution particularly to its tonic, diuretic, and wide array of immunopotentiating features. The plant is majorly distributed in the cool arid continental localities such as the Northern Hemisphere, South America, South West Asia, the Sino-Himalayan region, West North America, and along the Andes in South America. The plant is also diverse in the Mediterranean climatic regions along the Pacific coasts of North and South America, southern Europe, and northern Africa, as stated in the Korean Journal of Plant Taxonomy, p16. There have several challenges on classification of the plant considering the number of species in the market regarded as A. mahoschanicus. The species include
A. floridus, A. chrysopterus, A. hoantchy, A. tongolensis, A. tribulifolius, A. aksuensis, A. ernestii, A. lehmannianus, and Hedysarum polybotrys. Some pharmacognostical studies also reveal the relationship with the taxa of A. penduliflorus. Besides the problems associated with infrageneric taxonomy, species delimitation is a general genius problem. According to Sinclair in the Chinese Herbs, a Clinical Review of Astragalus, Ligusticum, and Schizandrae p.350. It is stated that some discriminating morphological and geographical features are less, which contributes to problems of clear taxonomic alignment. Discrimination of the drug sources from Astragalus membranaceusis often crucial classical botany, molecular systematic, and pharmacognosy to establish the different with other species. The height of the plant differs depending on area of origin and usually 50-100cm in China and South Korea and 40-70cm from China. The plants from china and South Korea are singular with erect stem form while from Japan exist in tufted and erect, ascending, and decumbent forms.

Historical Origin of the Use of Astragalus membranaceus

Application of Astragalus membranaceusunderwent a series of changes for the past 50 years due to some medical concerns: increased use of chemotherapy for cancer and the rising cases of cardiovascular diseases. Before the influence of the modern trends, the plant was in great repute as tonic, diuretic medicine, and pectoral involving alleviation of heart and lungs disorders at the end of 19th century. Sheng Nong was the founder of the Chinese herbal medicine around 5000 years ago, discovered the plant, and classified it as a superior herb in his classical treatise as stated by Rai, Acharya and Rios in the book titled Ethnomedicinal plants, pp.107.

TCM utilized the herb for night sweats, diarrhea, and deficiency of chi including fatigue, weaknesses, and appetite loss. Astragalus membranaceusis the oldest medicinal plant dating to about 200 BCE. Initially, the roots of the plant was listed as the top grade herb and used to balance the body system especially the lungs and spleens. The yellow colour of the root contributes to its Chinese name “huang qi” which means “yellow leader.”
In China, the plant has been used for thousands of years in strengthening qi, the body’s life force, and protection of the energy (Research Trade, Inc 8(1):72-77). In the Western terminologies, it means strengthening the immune system. For more than 2000 years, herbalists have used the plant to assist in building up the energy of the body and resistance of the diseases. It is the commonly utilized her in the Chinese medicine with the conventional medical practitioners recently becoming interested in the exploration of the herb citing that it might have less side effects of chemotherapy.

Astragalus membranaceus Part Used in Western Herbal Medicine Practice

The commonly used part of the plant is the root used in preparation of decoctions, liquid extracts, and tablets. The roots can be dried for decoctions or crushed for powder. With the rising rates of diabetes, there is need for potent drugs that complement the current anti-diabetic drugs. The roots of the plant are a key component in anti-diabetic formulas and shows significant prospect for the required compounds in the modern medicine. Various ethnopharmacological studies show that the plant’s roots can alleviate diabetes mellitus. Extracts from the roots are also important in current research to find the cure for HIV. This is in accordance to Bennett and Balick on Plant Taxonomy for Preclinical and Clinical Medicinal Plant Researchers pp.155. TAT2 is an extract from the roots that act on the cells within the immune system called telomeres. During the progression of HIV, there is shortening of telomeres and impediment of the body’s ability to replicate the immune cells.

World health Organisation report on Quality control methods for herbal materials, pp.4, it is stated that
TAT2 slows shortening of the telomeres and increases the body’s production of chemokines and cytokines, which assist in blocking proliferation of the HIV virus. For the patients with systemic lupus erythematosus, extract from the plant offer protective effect on the erythrocyte deformability. Decoctions from the roots are also important for common cold, upper respiratory infections, fibromyalgia, anaemia, and strengthening and regulation of the immune system. Some manufacturers also utilize the plant for general tonic, protection of the liver, and fighting viruses. In combination with other medicinal herbs such as Ligustrum lucidum, the extracts from the roots of Astragalus membranaceusare important in treating breast, cervical, and lung cancer.

Description of the Supply Chain

With the ever-rising use of medicinal herbs, the supply chain continues to rise even to countries that initially did not believe in medicinal herbs. Medicinal herbs are cost effective compared to conventional medicines with minimum side effects in question. International trade on the medicinal products is on the rise with the value chain becoming more complex and governed using an array of public and private standards. With regard to the supply chain, debates are currently ongoing on the extent to which the phytomedicine production can offer beneficial services for the farmers within the low and middle-income countries (140(3):624-633pp.627). Even with development in the industry, there are factors increasing the risk of the foundation laid by the supply chain including climate change, natural and manmade disasters, the geopolitical unrest, developments that cause habitat losses, and the ever-changing socio-economic conditions. Even though climatic conditions favor the growth of the supply chain of Astragalus membranaceus in some regions, also the major factor continues to reduce the reliance of the herb (140(3):624-633, pp.74). The chain socioeconomic conditions influence the supply chain since the old traditional collection of medicinal plant continue to end in most regions as people focus on utilizing conventional medicines.

Recognized Dominant Chemical Constituents

The major chemical constituents from Astragalus membranaceusextracts are polysaccharides, saponins, flavonoids, amino acids, and trace elements. Extract from the plant’s roots contain a series of cycloartane triterpene glycosides often referred to as atragalosides I-VII (the saponins) based on the aglycone
cycloastragenol. Glycosides contain from three different sugars attached at various positions including 3-, 6-, and 25- (9, pp.187). Within the predominant astragalosides I-III, there is acetylating of 3-glucose. The polysaccharides within the plant are very important especially fraction F3 that plays significant roles associated with immunomodulatory actions. The present polysaccharides are A, B, and C which are glucans while D is a heteropolysaccharide. While utilizing the high performance liquid chromatography (HPLC) in analyzing the flavonoids with the roots of Astragalus membranaceus, the electrospray ionization mass spectrometry reveal the availability of eight flavonoids.

The flavonoids include formononetin-7-O-beta-D-glucoside-6′-O-malonate, calycosin-7-O-beta-D-glucoside, (3R)-7,2′-dihydroxy-3′,4′-dimethoxyisoflavan-7-O-beta-D-glucoside, calycosin-7-O-beta-D-glucoside-6′-O-malonate (2), ononin, (6aR,11aR)-3-hydroxy-9,10-dimethoxypterocarpan-3-O-beta-D-glucoside, and formononetin. Other important chemical constituents available in the plant are amino acids, volatile oil, and phytosterols. The major amino acids are gamma-aminobutyric acid (GABA) and L-canavanine (10, par.7). The roots of the plants also contain various minerals such as zinc, manganese, calcium, magnessioum, copper, sodium, molybdenum, chromium, vanadium, rubidium, tin, cobalt, and silver. Other trace elements include tantalum, hafnium, europium, and thorium. There are several organic materials within the roots including choline, betaine, gluconic acid, and β-sitosterols. The aromatic compounds, important oil, linoleic acid, α-aminobutyric acid, bitter compounds, and asparagines are other important chemical materials found within the plant.

Assay Methods Used For Constituent Identification

Medicinal plants usually have great diversity of active compounds, which makes it difficult to acquire good separation performance of all the chemical compounds. Due to complexity of the Astragalus membranaceusconstituents, analysis of such complex compounds often pose great challenge for the pharmaceutical analysts (11, par.7). The appropriate method of detection is through using rapid, sensitive and selective liquid chromatography–tandem mass spectrometry detection as it improves detectability and selectivity by engaging multiple-reaction monitoring (MRM) acquisition. MRM has high selectivity mode that ensures accuracy of the method and optimization of chromatographic separation. Precursor and production monitoring is important as it increases specificity of detection and identification of the actual constituents of the plant.

The glycosides could be analyzed using both positive and negative ionization. The HPLC-MS/MS with positive ionization and the MRM mode often provide the highly selective method of determining the targeted compounds. HPLC-MS/MS is a multi-component analysis used in controlling the quality of most TCM, which is often limited due to shortage of different chemical references. The method provides huge amount of data more rapidly and efficiently than other methods (14, pp. 114). Selectivity, sensitivity, and rapidity are the major factors that encourage application of quantitative and quantitative analysis using HPLC-MS method. The method also allows analysis of the metabolites and identification of the bioassays of the complex structures. With different fragmentor voltage levels within MS, the accurate mass measurements for the molecular ions and characteristic fragment ions often represent reliable identification criteria for complex plant extracts.

Commonly Applied GMP Processing and Extraction Methods

The World Health Organization (WHO) recommends compliance with good practice when producing medicinal herbs. According to WHO’s GMP, it is significant to ensure quality, safety, and efficacy while extracting chemical continents from medicinal herbs with complex biological origins (7, pp.32). The selection methods used, whether cultivated or collected from the wild, is important and should comply with regulations stated in Good Agriculture and Collection Practices (GACP) meant for the medicinal plants. Postharvest often include primary cutting, which is clearly covered in the GACP, and further comminuting within the manufacturing process needs to be within GMP or any other supplementary guideline. Whenever cutting and comminuting reduce the chances of detecting adulteration or contributes to mix up of GMP for herbal medicinal materials, it is significant to apply the supplementary guidelines to cover the required steps. It is significant to handle the materials in fashion to prevent destruction to the product.

There is need to focus on the processing area taking into account the high microbial contamination of the medicinal plants. Such factors make classification of premises important as it covers the microbial contamination of the equipment, personnel, surfaces, utilities, and support system (7, pp.26). The herbs vary in composition and properties, which makes the quality control measures, procedures, and techniques substantially different from the other conventional pharmaceutical products. Due to the inherent complexity in the nature of the grown and naturally occurring medicinal herbs, there are some categorized as toxic plants due to the small quantity of the active ingredients. The production and primary processing method often influence the quality of the herbal medicine

Plant Therapeutic Actions

Several clinical researches show that the roots of Astragalus membranaceuscan stimulate the immune system in several ways. The components of the roots increase the amount of stem cells within the bone marrow and the lymph tissues and encourage their development into active cells of immunity. The plant assists in triggering the immune cells from their resting state into heightened activity, which in turn promotes and maintains the respiratory health. Astragalus membranaceuscan improve the production of immunoglobulin and ensure adequate stimulation of the macrophages within the body. The extracts from the plant also assist in the activation of the T-cells and the Natural killer (NK) cells and proffering the heart-protecting effects including safeguarding against the oxidative damages. The chemical constituents of the plant such as flavonoids, saponins, and polysaccharides within the plant assist in minimzing the free radical damage to the membrane (6, pp.347).

Both flavonoids and saponins with the plant can hinder peroxidation of the membrane lipid generated through superoxide (O2-), hydrogen peroxide (H2O2), the ultraviolet rays (UV), with the polysaccharides having possession of weaker protective activity. Extracts from the plant improves the cardiovascular system especially within the clinical parameters associated with extreme myocardial infarct, congestive heart failures, and angina due to its antioxide activities. In the modern Chinese medicines, the plant is used in treating hepatitis. The herbal extracts from the plant contain astragalus, which might assist in utilizing the oxygen and in turn reducing fatigue. Due to the nature of the plant as an adaptogen, the chemical might assist the body in adapting to various physical stress associated with exercise.

Contraindications, Cautions, and Known Interactions

The roots of the plant might appear safe exploration of mutagenicity is significant. Continuous interaction with the plant could have immunostimulating effects making it interfere with the immunosuppressive effects associated with cyclosporine and the cortisone class of drugs. It is important to avoid consuming the extracts from the plant simultaneously with other immunomodulating drugs. Tinctures from the plant are unsafe for pregnant and breastfeeding women as it contain considerable amount of alcohol (15, pp.207). It is difficult to determine the level of toxicity of the plant as it is used commonly in combination with other drugs. The side effects are common among people combined products containing Astragalus membranaceus include heart palpitations, aspiration pneumonia, diarrhoea, and abdominal discomfort.

The common side effects among the traditional users are mild stomach upset and allergic reactions. Preliminary studies indicate the ability of the plant to decrease the blood sugar levels; much caution is required for patients with diabetes or hypoglycaemia. From the studies, the extracts might act as diuretic to increase urination which theoretically could lead to dehydration or metabolic abnormalities. If taken with drugs that increase the risk of bleeding, Astragalus membranaceusextracts also increase-bleeding risks. Examples of such medicines include anticoagulant, anti-platelet, and non-steroidal anti-inflammatory drugs. The extracts contain immune stimulating features, which could have effects on the drugs suppressing the immune system. Theoretically, consumption of tragacanth from the plant might reduce the absorption of the drugs consumed through the mouth. Consumption of Astragalus membranaceusmight potentiate the activities of lipid lowering herbs.

Dosage Range and Labeling Requirements

The plant is consumed in different methods including drying the roots through decoctions, liquid extracts, and tablets or capsule. Several factors determine the dosage of extracts from Astragalus membranceusincluding the age, health, and associated conditions of the users. For the dried roots through decoctions, it is important to consume about 10-30g per day with large doses meant for treating paralysis for most TCM. While consuming the liquid extracts, 4-8ml per day of the 1:2 extracts. While consuming the extracts, it is important to follow the dosage extracts on the product label (15, pp.214).

The recommended dose for the standardized extract is 250-500mg consumer three to four times in a day standardized to 0.4% of 4-hydroxy-3-methoxyisoflavone-7- glycoside. When consuming with tea, it is important to boil three to six grams of dried roots per 12 ounces of water three times a day. For medicinal tincture from the plant, 30% of ethanol is appropriate and the recommended dose is about 20-60 drops three times in a day. There is no established dosage for children with regard to consumption of the plant’s extracts. TCM holds that children suffering from the fever should refrain from taking the plant extracts as it might increase the fever making the prevailing condition to last longer. For interactions, safety, and dosing reasons, the extracts need to have appropriate labels. There is also need for discussions between qualified healthcare practitioner and the patient before commencing the therapy to ascertain consumption of the drug with the actual labels.


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