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НазваMedicinal plants (реферат)
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на тему:

 

Medicinal plants

 

Herbalism, also known as phytotherapy, is folk and traditional

medicinalpractice based on the use of plantsand plant extracts.

 

Finding healing powers in plants is an ancient idea. People in all

continents have long used hundreds, if not thousands, of indigenous

plants, for treatment of various ailments dating back to prehistory.

There is evidence that Neanderthals living 60,000 years ago in

present-day Iraq used plants for medicinal purposes. These plants are

still widely used in ethnomedicine around the world.

 

Plants have an almost limitless ability to synthesize aromatic

substances, most of which are phenols or their oxygen-substituted

derivatives such as tannins. Most 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 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.

 

The use and search for drugs and dietary supplements derived from plants

have accelerated in recent years. Pharmacologists, microbiologists,

botanists, and natural-products chemists are combing the Earth for

phytochemicals and leads that could be developed for treatment of

various diseases.--Dr M Tariq Salman 19:06, 30 January 2006 (UTC)

 

The use of herbsto treat diseaseis almost universal among

non-industrialized societies. A number of traditions came to dominate

the practise of herbal medicine in the Western worldat the end of the

twentieth century:

 

The Western, based on Greekand Romansources,

 

The Ayurvedicfrom India, and

 

Chinese herbal medicine(Chinese herbology).

 

Many of the pharmaceuticalscurrently available to Western physicians

have a long history of use as herbal remedies, including opium, aspirin,

digitalis, and quinine.

 

 

 

Biological background

 

All plants produce chemical compoundsas part of their normal

metabolicactivities. These can be split into primary metabolites, such

as sugarsand fats, found in all plants, and secondary metabolites found

in a smaller range of plants, some only in a particular genusor species.

 

 

The autologousfunctions of secondary metabolites are varied. For

example, as toxinsto deter predation, or to attract insects for

pollination. It is these secondary metabolites which can have

therapeutic actions in humans and which can be refined to produce drugs.

Some examples are inulinfrom the roots of dahlias, quininefrom the

cinchona, morphineand codeinefrom the poppy, and digoxinfrom the

foxglove.

 

As of 2004, the National Center for Complementary and Alternative

Medicine started to fund clinical trialsinto the effectiveness of herbal

medicine.

 

Some surveys of scientific herbal medicine can be found in

Evidence-based herbal medicine edited by Michael Rotblatt, Irwin Ziment;

Philadelphia: Hanley & Belfus, 2002, and Herbal and traditional

medicine: molecular aspects of health, edited by Lester Packer, Choon

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