Herbalism is a traditional medicinal or folk medicine practice based on the use of plants and plant extracts. Herbalism is also known as botanical medicine, medical herbalism, herbal medicine, herbology, and phytotherapy. Sometimes the scope of herbal medicine is extended to include fungi and bee products, as well as minerals, shells and certain animal parts.

Many plants synthesize substances that are useful to the maintenance of health in humans and other animals. These include aromatic substances, most of which are phenols or their oxygen-substituted derivatives such as tannins. Many are secondary metabolites, of which at least 12,000 have been isolated — a number estimated to be less than 10% of the total. In many cases, these substances (particularly the alkaloids) serve as plant defense mechanisms against predation by microorganisms, insects, and herbivores. Many of the herbs and spices used by humans to season food yield useful medicinal compounds.

All plants produce chemical compounds as part of their normal metabolic activities. These include primary metabolites, such as sugars and fats, found in all plants, and secondary metabolites found in a smaller range of plants, some useful ones found only in a particular genus or species. Pigments harvest light, protect the organism from radiation and display colors to attract pollinators. Many common weeds have medicinal properties.

The functions of secondary metabolites are varied. For example, some secondary metabolites are toxins used to deter predation, and others are pheromones used to attract insects for pollination. Phytoalexins protect against bacterial and fungal attacks. Allelochemicals inhibit rival plants that are competing for soil and light.

Plants upregulate and downregulate their biochemical paths in response to the local mix of herbivores, pollinators and microorganisms.The chemical profile of a single plant may vary over time as it reacts to changing conditions. It is the secondary metabolites and pigments that can have therapeutic actions in humans and which can be refined to produce drugs.

Plants synthesize a bewildering variety of phytochemicals but most are derivatives of a few biochemical motifs.

Tuesday 27 May 2008

ASTRAGALUS



Introduction

This fact sheet provides basic information about the herbA plant or part of a plant used for its flavor, scent, or potential therapeutic properties. Includes flowers, leaves, bark, fruit, seeds, stems, and roots. astragalus—common names, uses, potential side effects, and resources for more information. Native to China, astragalus has been used for centuries in traditional Chinese medicineA whole medical system that originated in China. It is based on the concept that disease results from disruption in the flow of qi and imbalance in the forces of yin and yang. Practices such as herbs, meditation, massage, and acupuncture seek to aid healing by restoring the yin-yang balance and the flow of qi.. In the United States, the herb gained popularity in the 1980s. There are actually over 2,000 species of astragalus; however, the two related species Astragalus membranaceus and Astragalus mongholicus are the ones primarily used for health purposes.

Common Name—astragalus, bei qi, huang qi, ogi, hwanggi, milk vetch

Latin Name—Astragalus membranaceus, Astragalus mongholicus

What It Is Used For
  • Historically, astragalus has been used in traditional Chinese medicine, usually in combination with other herbs, to support and enhance the immune system. It is still widely used in China for chronic hepatitis and as an adjunctive therapy in cancer.
  • It is also used to prevent and treat common colds and upper respiratory infections.
  • Astragalus has also been used for heart disease.


How It Is Used
The root of the astragalus plant is typically used in soups, teas, extracts, or capsules. Astragalus is generally used with other herbs, such as ginseng, angelica, and licorice.

What the Science Says
  • The evidence for using astragalus for any health condition is limited. Results from small or preliminary studies suggest that astragalus may benefit heart function and help the immune system fight infections.
  • A few studies have shown potential benefits for using astragalus—in combination with another herb, glossy privet (Ligustrum lucidum)—as an adjunctive therapy for cancer. In general, however, these studies were not well designed.
  • NCCAM-funded investigators are studying the effects of astragalus on the body, particularly on the immune system.


Side Effects and Cautions
  • Astragalus is considered safe for most adults. Its possible side effects are not well known because astragalus is generally used in combination with other herbs.
  • Astragalus may interact with medications that suppress the immune system, such as the drug cyclophosphamide taken by cancer patients and similar drugs taken by organ transplant recipients.
  • People should avoid using astragalus species such as "locoweed" that grow in the United States, as these other species may have different effects and side effects.
  • Tell your health care providers about any complementary and alternative practices you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care.
Sources
* Astragalus. Natural Medicines Comprehensive Database Web site. Accessed May 10, 2007.
* Astragalus (Astragalus membranaceus). Natural Standard Database Web site. Accessed May 9, 2007.
* Upton R. Astragalus. In: Coates P, Blackman M, Cragg G, et al., eds. Encyclopedia of Dietary Supplements. New York, NY: Marcel Dekker; 2005:25–30

Posted by AGID at 10:29

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