MEDICINAL HERBS

I

The principal parts of a plant are: 1) the root system, 2) the stems and leaves, 3) the reproductive part made up of flowers, fruits or seeds.

The roots grow downward into the soil and have two main functions – to absorb plant nutrients and water from the soil and to anchor the plant. As to stems and leaves, they are usually above the ground. The food used in growth by green plants is manufactured in the leaves from the raw materials taken from the soil and air. This process is known as photosynthesis. To support the leaves and to connect them with the roots are the main functions of the stem. A flower is the part of the plant where seeds are produced. Thus, to produce seeds the plant must have flowers.

Herbal medicine - also called botanical medicine or phytomedicine refers to using a plant's seeds, fruits, roots, leaves, bark, or flowers for medicinal purposes. Plants that give drugs have both active substances, the so-called primary plant products, and inactive substances, the so-called secondary products. Therapeutic efficacy of plants varies during different times or seasons of the year. The constituents and active principles vary in quantity at different seasons of the year and the majority of plant materials are usually best collected during the dry season, when the herbs are at peak maturity and concentration. Roots and rhizomes: Best collected from October to February, when the plants are more vigorously storing food in their underground organs.

Leaves: The most opportune time is when the plant is about to bloom.

Flowers: Best collected in the time of pollination. Buds are preferred, collected in the morning after the morning dew has evaporated; flowers, just before or shortly after opening. Dry the herbal materials as quickly as possible.

Bark materials and stems: Generally, best gathered in summer time. When the climate is warm and humid, the bark of any plant usually contains richer nutritive substances including the medicinal metabolites.

Fruits and seeds: Fully ripened fruits and mature seeds are preferred. Turn the fleshy fruit frequently for even drying.

Whole plant: When the whole plant is desired, it is advisable to harvest the plant at the time when the flowers are all in bloom.

II

The moisture content of the dried plant materials should be less than 10% before storage.

The dried plant materials should be placed in plastic containers or tightly covered bottles. The storage place should be dry, well-ventilated, and spacious. Drug materials can be kept in large open wooden shelves. If all factors are favorable, the prepared drugs can be used even after years of storage.

The odour of a drug of plant origin may be distinct or indistinct, depending upon the amount of volatile constituents the drug possesses. It is described as aromatic, balsamic, spicy, camphorous, etc. When it is difficult to compare the odour with other substances it is described as characteristic.

According to taste substances may be classified into four groups:

1. Those possessing a true taste, such as acid, sweet, alkaline, bitter;

2. Those possessing no taste and thus are tasteless;

3. Those possessing a characteristic odour which gives name to the

so-called “taste”. They may be grouped broadly into those which are agreeable or pleasant (aromatic, balsamic, spicy) and disagreeable or unpleasant (alliaceous, camphorous, etc.);

4. Those giving certain sensation to the tongue (mucilaginous, oily,

astringent, pungent, acrid, nauseous.

Pharmacological activity of certain drugs is established using different tests and methods, such as chemical tests for the determination of presence of inorganic elements, a chemical analysis for the determination of presence of inorganic elements, a chemical analysis for the determination of the official activity, chromatographic study to separate and analyze constituents and inert materials occurring in drugs.

Exercise 1. Finish the following sentences.

1. Herbal medicine is also called … . 2. Primary plant products are called … . 3. Secondary plant products are also called … . 4. Flowers are best collected in … . 5. Bark materials and stems are best gathered in … . 6. Roots and rhizomes are collected in … . 7. It is advisable to harvest the whole plant when … . 8. The storage place should be … . 19. Drug material can be kept in … .

Exercise 2. Insert the proper words from the list instead of gaps.

Agreeable, tasteless, spicy, odourless, characteristic, pale-yellow, disagreeable

1. A … odour gives name to the so-called “taste”. 2. Aromatic, balsamic and spicy taste is considered as an … taste. 3. Alliaceous, campharous, etc. taste is considered as …. 4. Substances possessing no taste are called …. 5. The taste of rhizomes and roots of valerian may be described as …. 6. Olive oil may be described as … liquid which sometimes has a greenish taste. 7. Reserpine is described as a “white or pale to slightly yellowish, … , crystalline powder.

Exercise 3. Put the questions to which the following will be the answers.

1. The majority of plant materials are usually best collected during dry season. (When?). 2. The dried plant material should be stored in plastic containers or tightly covered bottles. (What?). 3. Yes, therapeutic efficacy of plants varies during different times or seasons of the year. (Does?). 4. According to taste substances may be classified into four groups. (How many?). 5. Plants giving drugs have both active and inactive substances. (What?). 6. The taste, colour and odour of medicinal plants are standardized by describing lightness and strength of their colour. (How?)

Exercise 4. Answer the following questions.

2. What is the best season of the year to collect the following parts of medicinal plants and why?

a) roots and rhizomes;

b) leaves;

c) bark;

d) flowers;

e) fruits and seeds.

3. Is it advisable to collect the whole plant when it is old or is in bloom?

4. What are the main rules for storing the dried plant materials taking into consideration a) the storage place itself; b) the humidity of the place; c) types of containers?

5. What is the classification of drugs of plant origin according to a) odour; b) taste?

6. What tests and methods are used to establish pharmaceutical activity of certain drugs?

1. Многие растения используются в современной фармацевтической промышленности.

2. Популярные напитки, такие как кофе, чай и какао, получают из определенных частей растений.

Text 2

1. Without plants there would be no life on Earth. In ancient times, plants played a vital role in healing, and many are still used by the modern pharmaceutical industry.

2. The Assyrians and Egyptians, the early civilized people started cultivating plants. By the seventh century they had produced a systematically arranged list of medicinal plants. In China medical authorities recognize the medical properties of more than 5,800 plants. They classified the medicinal effects of the plants on the various parts of the body, then tested them to determine their toxicity, what dosages would be lethal, and so forth. For example, cassia bark is warming in nature, and is useful in treating colds*. Mint is cooling in nature, and is used to relieve the symptoms of illness resulting from heat factors.

3. One of the most widely used plant that was known to man 5000 years ago is garlic. It is well known that garlic is therapeutically useful for the following purposes: it is a powerful agent in preventing diphtheria, typhus, tuberculosis, pneumonia; it is useful in all respiratory infections, especially in symptoms of a dry hacking cough*, in colds, asthma and bronchitis, and in many other cases. It is also an excellent nerve tonic.

4. Valerian (Valeriana officinalis) is a popular alternative to commonly prescribed medications for sleep problems. Unlike many prescription sleeping pills, valerian may have fewer side effects such as morning drowsiness.*

5. Clinical studies found that Echinacea supplements decreased the chance of getting a cold by 58%. It also shortened the duration of a cold by 1.4 days.

6. Used correctly, herbs can help treat a variety of conditions and in some cases may have fewer side effects than some conventional medications. But some herbs may cause allergic reactions and some are toxic if used improperly or at high doses. Taking herbs on your own increases your risk, so it is important to consult your doctor or pharmacist before taking herbal medicines.

7. Plants have been used by people not only as source of medicines but for some other purposes. They supply people with food and many other useful products. They also add beauty and pleasure to people’s life. Flax has been used for centuries for its fibers and linseed oil. Paper money is made from fibers of flax. Popular drinks such as coffee, tea, and coconuts are all made from parts of plants. Chocolate is made from the fruits of cocoa (Theobroma cacao). Although the modern perfume industry can make perfumes artificially, it still relies on essential oils* extracted from flowers such as rose, lavender, jasmine and orange.

*cold - простуда

*hacking cough – кашель (отрывисты и сухой);

* drowsiness – дремота;

* oil – масло (обычно растительное или минеральное);

Exercise 1.Make up sentences.

Exercise 2. Define the statements as TRUE or FALSE.

1. The Egyptians tested plants to discover their nutritional and medicinal properties.

2. Garlic was known to men 2000 years ago.

3. Garlic is considered as antimicrobial drug.

4. Extracts from Ginko plants are widely used by the Europeans as an agent to counteract the effect of aging.

5. Valerian is effective in sleep problems.

6. Medicinal plants may not have any adverse effects.

7. Essential oils extracted from flowers of some plants are not used in perfume industry because modern perfume industry can make perfumes artificially.

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Exercise 3. Read an article about tea. Choose from the list A-H the sentences which best summarize each part (1-6) of the article. There is one extra sentence which you do not need to use. There is an example at the beginning.

The flowers described: rose, chamomile, lilly-ofthe-valley, calendula.

You are going to read an article about tea. Choose from the list A-H the sentence which best summarizes each part (1-6) of the article. There is one extra sentence which you do not need to use. There is an example at the beginning (0).

Text 3

Date: 2014-12-22; view: 2428