MEDICINAL HERBS

Discover the Medicinal Value of Plants

Medicinal herbs are plants which contain chemicals which have an effect upon the body (usually the human body, but sometimes animals as well). The effect of medicinal herbs may be mild or strong depending on a number of things including: 

• The species and variety of plant - NB: there can be subtle but important differences between two plants which may appear to be identical. For example many herbs now sold are cultivated varieties of the original species and may not have the chemical constituents of the species form.
• Species that have the same common name but are totally different and unrelated - one could be highly poisonous the other benign
• How it was grown - herbs that are over fertilised and watered tend to have a lower concentration of the important chemical constituents.
• The part(s) of the plant used - root, leaf, stem, flower, fruit, mature or new growth
• Harvest time - time of day, time of year, weather conditions at the time
• The preparation of the medicine - as an oil, tablet, tea, ointment 
• The storage of the medicine - some medicines store well, but generally fresh is best
• How it is used - some herbs may be safe to use externally, but the same herb may be a serious problem if taken internally. Some may be beneficial in a certain concentration, but dangerous in a different concentration.

Add medicinal herbs to your plant knowledge

In this course you will learn what constitutes a medicinal herb, how to identify them, and how different plants and plant parts are used. You also learn about which soils are suited to growing herbs, water and fertiliser requirements, how to propagate them from seeds or cuttings, and control of pests and diseases. Cultural requirements for many of the most widely grown herbs are provided along with their uses and methods for preparing herbal remedies. 

Lesson Structure

There are 8 lessons in this course:

1. Introduction to Medicinal Herbs
   • Scope and Nature of Herbal Medicine
   • Being Cautious
   • Growing and Knowing Medicinal Herbs
   • Accurate Plant Naming
   • Pronouncing Plant Names
   • Finding Reliable Resources
2. Culture of Medicinal Herbs
   • What is a Herb
   • Soils and Nutrition
   • Cultivation
   • Fertilizing Herbs
   • Compost, Mulch, Watering
   • Propagation
   • Pest and Disease
3. History
   • Introduction
   • Hippocrates
   • Chinese Herbalists
   • Egyptian Influence
   • Greek Influences
   • The Dark Ages
   • German and English Herbals
   • Other Influences
4. Main Medicinal Herbs
   • Introduction and Varieties to Grow
   • Production Plan
   • Improving Soil Fertility
   • Cover Crops and Legumes
   • Cultivation, Growing Methods, Compost
   • Growing and using Ginger
   • Garlic Culture
   • Echinacea Culture
5. Herbal Remedies
   • Alternatives
   • Anthelmintics
   • Astringents
   • Bitter Tonics
   • Calmatives
   • Carminatives and Aromatics
   • Cathartics
   • Diaphoretics
   • Dietetics
   • Demulcents
   • Emollients
   • Expectorants
   • Nervines
   • Relaxants
   • Vulnerary Herbs
   • Common Herbs with Medicinal Properties
   • Nervines as Healing Agents
   • Natural Chemicals in Plants and their Affect on Health; saponins, phenolglycosides, anthraglycosides, flavonoids, mustard oils, polysaccharides, prussic acid, glycosides, coumarin, tannins, bitters, essential oils, alkaloids, purines, essential minerals
   • Chemistry of Herbs
   • Herbal Sources for Human Nutrients
6. Preparing Herbal Remedies
   • Infusion
   • Decoction
   • Poulice
   • Medical Preparations
   • Problem of Accurately Formulating Herbal Medicines
   • How herbalists used to work
   • The Difference Today
   • Harvesting Material for Herbal Preparations
   • Post Harvest Handling of Herbs
   • Post Harvest Preservation; Fresh, Modified Atmospere Packaging
   • Herbal Preparations for Teas, Rinses and Baths
   • Producing Essential Oils; Water distilation, Steam distilation
   • Uses for Eucalyptus Oil
7. Poisonous Plants
   • Introduction
   • Review of Plant Poisons
   • Hazardous Herbs
   • Carcinogens, Potosensitizers, Allergens, Hormone Like Affects, Teratogens, Respiratory Inhibitors, etc
   • Toxic Plant Constituents
8. Developing a Production Plan
   • Managing a Market Garden
   • Deciding What to Grow
   • Production Planning
   • Types of Problems
   • Standards
   • Crop Schedules
   • Farming Medicinal Herbs
   • Production Requirements for Different Herbs

Aims

• Distinguish between medicinal herbs in cultivation
• Discuss the history of medicinal herb usage.
• Compare the chemical components of different medicinal herbs in terms of their general affect on the human body.
• Prepare simple and safe herbal remedies in a domestic situation.
• Explain the potential dangers involved in dealing with plants.
• Prepare a schedule of cultural practices for a medicinal herb crop.
• Develop a production plan for a medicinal herb crop.

What You Will Do

• Explain the characteristics of different types of chemicals found in medicinal herbs.
• Write brief definitions to explain the mode of action of different herbal medicines.
• Describe chemical actions which two different herbs have upon the human body.
• Explain various factors which can influence the effectiveness of active constituents of a herb.
• List herbal remedies derived from different commonly grown herbs.
• Identify the morphological parts of different herbs which are used medicinally.
• Explain thoroughly how to prepare different types of simple medicines, including a: *Poultice *Infusion *Decoction *Tincture.
• Develop a list of safety procedures to follow when preparing a given herbal medicine.
• Explain methods to administer different herbal medicines which are safe and appropriate for an unskilled person to make and use at home. (ie. medicines which do not have any dangerous risks if prepared or administered incorrectly).
• Describe commonly occurring plants which contain poisonous substances, including: *names (botanical and common) *dangerous parts of the plant *poisonous substances *mode of action of poison *remedy (if any).
• List herbs that should never be taken internally.
• List herbs which should never be used by pregnant women.
• List herbs which should never be used by children.
• Describe precautions when dealing with unknown herb materials.
• Develop guidelines for the culture of a specified variety of medicinal herb.
• Explain natural pest and disease control methods for medicinal herb varieties.
• Prepare a sample of soil suitable for growing a specified herb variety in the open ground.
• Demonstrate propagation techniques for different medicinal herbs.
• Produce container plants of different medicinal herbs, propagating and growing on the plants to a marketable stage and condition.
• Record the development of medicinal herbs in a log including a summary of the condition of the plant, growth, and cultural practices carried out.
• Develop a list of criteria for selecting the most commercially viable variety of a nominated medicinal herb species available.
• List thirty different varieties of a medicinal herb species which are readily available for purchase as "reliable" seed or tubestock.
• Compare different varieties of nominated medicinal herb species to determine a commercially viable variety to grow in your locality.
• List tasks to be undertaken in the production of a selected medicinal herb variety, including: *soil preparation *planting *growing practices *harvest and post harvest.
• Write a production schedule for a medicinal herb variety which designates tasks to be undertaken systematically at each stage of crop development.
• Explain the facilities which would be required to produce a specified commercial medicinal herb crop, including: *equipment *materials *land.
• Estimate the cost of producing a specified medicinal herb crop, itemising the cost components into different categories.
• Define the term "medicinal herb" according to both horticultural and naturopathic meanings.
• Compile a resource file of different sources of information regarding medicinal herbs.
• Distinguish between different plant families which common medicinal herbs belong to.
• Prepare a plant collection of fifty different medicinal herb varieties.
• List ten different medicinal herbs which were often used more than one hundred years ago, but are no longer commonly used.
• Identify modern trends in the use of herbs in medicines in your country.
• Discuss the role of home remedies in modern society.
• Discuss the role of the naturopath in modern society.
• Summarise the history of medicinal herbs since early civilisation, to modern times.

NATURAL CHEMICALS IN HERBS AND THEIR EFFECTS ON HEALTH

Many of the plants which we use to prepare comforting and healing teas, baths, dressings, wines and other remedies can readily be found in the average kitchen. Sage, bay leaves, thyme, onions, cinnamon, anise, cardamon and lemons are just a few examples of kitchen foods with medicinal properties. Onions for example, can dissolve away dangerous blood clots in the blood vessels. Similarly, lemons have long been consumed by sailors on long voyages for their vitamin C content which prevents scurvy.
 
Other plants (which may not be eaten regularly as a food) can be taken as tonics to protect against disease and poor body function, or as alleviants for pain and illness. In many cases, properly extracted and combined plant substances can still be the safest, most effective and economical way of providing medicinal relief.
 
 
Plant Chemical Groups which; cure, protect and alleviate include the following:
 
Group 1: Saponins
 
Saponin containing plants are characterised by soap like foam when they are shaken in water. For this reason, many native peoples throughout the world have long used saponin‘containing plants for cleansing.
 
Basically they act to speed up the passage of other substances through the walls of the gastrointestinal tract and to stimulate secretion from the mammary glands and glands along the respiratory tract.
 
Saponin containing plants can be used as:

a. Expectorants (ie. phlegm removing substances) eg. primrose roots, mullein flowers and leaves, lungwort leaves.;

b. Diuretics (ie. substances which increase the flow of urine) eg. golden rod leaves, Java tea leaves.

 c. Lactation stimulants. Nursing mothers have used goat's rue for this purpose.

They have also been used to help re establish the smooth functioning of body fluids eg. pansy and horsetail leaves.

 
Group 2: Phenolglycosides
 
There are two particularly significant types of phenoglycosides:
 
1. Arbutin  has a disinfecting action on the urinary tract when the urine is alkaline eg. blueberry and bearberry leaves.
 
2. Salicin is chemically related to the salicylic acid in aspirin, therefore is useful in reducing fever and relieving pain eg. pansy leaves, willow bark, poplar leaves and bark.
 

Group 3: Anthraglycosides
 
In this group, Anthraquinone (also called emodin), is used to relieve constipation eg. senna leaves, aloes, buckthorn, rhubarb.
 
 
Group 4: Flavonoids
 
Some flavonoids can act to stimulate the cardio vascular system; others have diuretic properties, whilst others inhibit infections. Rutin, one of the flavonoids, has an anti haemorrhagic effect. It also helps the blood vessels to expand, thereby lowering blood pressure. Examples of flavonoid containing plants are chamomile flowers, juniper berries, broom leaves, linden blossoms, hawthorn flowers and birch leaves.
 

Group 5: Mustard Oils
 
Plants that contain mustard oil glycosides can be used as rubefacients i.e. can improve the blood circulation near the surface of the skin. They can be particularly useful for relieving breathing problems during colds and bronchitis. Mustard oil glycosides also have antibiotic properties eg. water-cress.
 
Group 6: Polysaccharides
 
The polysaccharide group includes pectin which acts to control diarrhoea and bleeding; mucilage which soothes inflamed mucous membranes, and inulin. Fructose results from the digestion of inulin which is readily metabolised in the body and is converted into glycogen ("animal starch") even when insulin is lacking. Mucilage containing plants are linseed, marshmallow root, coltsfoot leaves and mullein. Pectin is found in fruits such as apples.
 
 
Group 7: Prussic Acid
 
Prussic acid has a local anaesthetic effect. It is found in almonds and may be one of the reasons for the relief given to dry, chapped skin when almond oil is used.
 
 
Group 8: Glycosides
 
Digitalis glycoside (from the leaves of the foxglove), convallatoxin glycoside (from lily of the valley), and oleandrin (from oleander), are natural chemical compounds which have an effect on the heart muscles. These should only be used with extreme caution as they contain toxins which can be fatal.
 
 
Group 9: Coumarin
 
Coumarin containing plants such as woodruff are used to prevent or dissolve blood clots or thrombotic clots.
 
 
Group 10: Tannins
 
Tannins have a mild astringent effect on the skin. They also have disinfectant properties, and can help to combat diarrhoea. Examples of plants that contain tannins are walnut leaves, sage leaves, blueberries, and oak bark.
 
 
Group 11: Bitters
 
Bitters promote bile secretion, improve the uptake of nutrients from the gastrointestinal tract, and stimulate digestive juices. They also combat gastrointestinal fermentation. Plants which contain bitters are angelica root, milfoil leaves, gentian root and wormwood foliage. These four plants are called aromatic bitters because they also contain essential oils.
 
 
Group 12: Essential Oils
 
When heated, essential oils (also called aromatic, volatile or ethereal oils) will variously act to reduce inflammation, relieve cramping, promote milk flow, aid digestion, expel gas, disinfect, and sooth the nerves.
 
 
Group 13: Alkaloids
 
Alkaloids are nitrogen containing compounds with certain chemical characteristics such as reacting chemically like alkaline substances. They have many different effects on the human body, for example morphine and codeine in opium are well known pain relieving alkaloids. Nicotine in tobacco is also an alkaloid.
 
 
Group 14: Purines
 
Caffeine is a purine which increases the flow of urine and supports healthy heart function. Too much caffeine though will cause harmful over stimulation.
 
 
Group 15: Essential Minerals
 
Plants of all kinds contain minerals which are essential for good health. For example, spinach contains large amounts or iron and Vitamin A; horsetail is rich in silicon which acts to clear up the symptoms of arteriosclerosis; bladder wrack seaweed is rich in iodine which is used to treat people with goiter and obesity.