Herbal medicine is the use of herbs (plant leaves, stems, roots) as medicine. By contrast, modern medicine isolates one active ingredient either from plants or synthetically by chemical reactions.

Eucalyptus is one example of a natural product used for medicine.  It is 

                                commonly used for colds and respiratory ailments.

1. How long have humans used plants as medicine?

• 3,500 year old Egyptian writing (Ebers papyrus) describes a remedy using garlic
• Ancient China's emperor, Shen-nung lived 4,500 years ago and his recipes were published in 1600 in a book called the "Pun-tsao"
• India's system of medicine dates back several thousand years to sacred writings called the Rig-veda
• The Aztecs lived in Mexico for thousands of years.  Aztec herbal medicines were documented in a book published by the Spanish invaders in 1592.  The book is called the Badianus manuscript.

A brief history of herbal medicine use around the world:

a. Canada 1500's

    European explorer Jacques Cartier had sailors stricken with scurvy (vitamin C deficiency).  Native Americans brewed up a tea of yellow cedar bark (contains vitamin C) and cured them.  Why were British sailors called "limeys"?

b.   England 1800's, the discovery of digitalis

                Dr. William Withering found a woman herbalist who was treating "dropsy"--congestive heart failure which causes fluid accumulation in lower extremities.  He figured out Purple Foxglove contained the active ingredient.  Until recently, digitalis has been the choice of medicine as a heart stimulant.    

c.  U.S. 

     1700's 

                Ginseng was shipped to Asia for $1 per pound--as valuable as furs.  Early Europeans who explored Kentucky (including Daniel Boone) were looking for ginseng. Today, wild ginseng in the U.S. can sell for over $300 per pound.p.324

     1800's

               1) Regular physicians used:

                            Bleeding, mercury, strong laxatives

                2) Samuel Thomson studied with Native American healers and mid-wives and popularized herbal extracts.  John Kellogg (Kellogg cereal's founder) was his successor.

d. Germany 1800's

    First drug extracted from herbs, morphine from the opium poppy for pain relief.  (p.346-347)

Other drugs that soon followed:

    Aspirin from willow bark for pain and inflammation (p. 331-333)

    Ephedrine from Chinese ephedra (Ma Huang)-a stimulant that is now illegal in the U.S. because it has been linked to heart problems.p.337

    Quinine from cinchona bark (used to treat malaria)(p. 333-335)

2. How important are herbal medicines today?

Herbs are often the primary source of medicines, especially in rural areas.  In developing (economically poor) nations, 75% of the rural population may use herbals.  In China, herbals are often combined with modern medicine p.327.

Although herbal medicines are not the primary source of medicine, in recent years more and more individuals are using herbal medicines. In the U.S., the sale of vitamins and herbs approached $10 billion in 1997.

25% of prescription drugs in the U.S. contain active ingredients derived from plants.

3. Specific plants and there uses.  Here are a few plants discussed in your text and their uses below.  Read about them in Chapter 19.

• What is the difference between a legal and illegal drug?

Many illegal drugs are extremely dangerous, but so are many drugs that are legal.   Legality is a cultural and social phenomena—not a biological one. Drugs illegal in one culture may be legal in another.

• What is the difference between a medicine and a poison?

Medicine or poison is often simply a matter of dosage. Aspirin is the most widely used drug in the world, yet can be lethal if taken in great quantity.

4. Why do plants produce medicines?

Insecticides: nicotine

Fungicides: garlic

Anti-bacterial: garlic

Anti-herbivore: Nerium oleander, jimsonweed

5. How would you go about finding and testing a new herb?

Use the knowledge of native peoples. Since tropical rainforests have great biodiversity, this would be a good place to start. Many plants of the rainforest have still never been seen by Westerners. When Westerners talk about discovering a new plant this way, it is similar to the concept of Columbus "discovering" America, i.e. native people already know about it!  See the work of Mark Plotkin's  Amazon Conservation Team. 

6. Testing plants as medicine

a. Test tube experiments

These experiments are inexpensive and many plants can be screened at one time. Example: Screening for antibiotic resistance on Petri dishes or screening HeLa cancer cells for anti-cancer compounds.

b. Animal models

Mice is the standard laboratory animal in use. Mice have been bred that will always develop certain diseases—diabetes or certain types of cancer, for example.

The nice part of using animals is you can control the environment so all mice are fed the same food, kept in the same living quarters and so on. Also, the mice will be similar in age and genes.

c. Human test

Double-blind studies

Control vs. Experimental group

Subjects and doctors do not know if they are in the control or experimental group. Only the scientist running the experiment knows. This prevents bias from entering the results.

Example: The new baldness drug, Propecia, was tested and found to stimulate hair growth in 42% of the control group and 86% of the experimental group. Why did 42% of the control group show hair growth? This is an example of the Placebo effect. If you believe something is helping you, then if often does help you. The Placebo effect is a very real demonstration of the power of positive thinking.

Example 2: The drug Vioxx has been pulled from the market because it increases the risk for heart attack and stroke. Vioxx recall

Clinical trials for U.S. prescription drugs*

*For more information, see Zivin, Justin, "Understanding Clinical Trials" in Scientific American, April 2000.

Exercise:

•  How many years? ______

• How much money does it cost to bring a new prescription drug to market? ____

• Add the columns above.

• Here are the number of adults in the U. S. who have asthma and mad cow disease.

• Asthma: 14,000,000 (14 million) adults in U.S.          

• Mad cow disease: 200 adults in U.S.

• If you are a pharmaceutical company, which disease would you target?  Explain.

                    Note: The Orphan Drug Act passed by the federal government in 1982 encourages companies to develop drugs to treat rare conditions.

•     Why would it make sense to use healthy volunteers for phase I studies?

• One of the largest drug-testing companies in the world has a facility in Chandler, AZ, Covance

6. Tropical rain forest preservation

Both the tropical rain forest and the native culture of the people that live in the rain forest are being destroyed.

Native people that live in the rain forest want to preserve it. However, often rain forests are in poor countries and a lot of money can be made by cutting down rain forests and selling the wood.

7. Alkaloids and glycosides are two types of molecules that form the building blocks of many plant medicines. p.329-330

Alkaloids: taste bitter, names end in -ine, about 3,000 alkaloids in 4,000 plant species have been identified

Examples: Nicotine from tobacco is a stimulant

Caffeine from coffee is a stimulant

Morphine from opium poppies is a pain killer

Quinine from the bark of cinchona trees treats malaria (unicellular protozoan in the genus Plasmodium)

Glycosides: have a glucose molecule attached and release cyanide when broken down

Examples: Diosgenin from yams which was used in the first birth control pills

Digitalis from the purple foxglove used to treat heart disease

Aloe vera sap used in burns

8. Cancer therapy by plants p.338

Examples of anti-cancer compounds in plants, can be seen on the "Cyberbotanica" internet assignment. Examples of cancer-fighting compounds are Vinblastine and Vincristine from the Madagascar periwinkle (Catharanthus roseus). This is used in treating Hodgkin’s disease. Side-effects are nausea and hair loss.

Cancer is cell division out of control

Terms:

Benign tumor: growth remains at original site, not capable of spreading

Malignant tumor: capable of spreading—you have cancer!

Has it metastasized? ( metastasized= spread)

400,000 cancer deaths each year. Half are from environmental causes and therefore preventable.

50% Genetic: Faulty DNA that you are born with lead to Cancer

50% Environmental: Exposure:   DNA damage leads to cancer

History of cancer prevention:

1775 England Sir Percival Pott observed cancer of the scrotum in chimney sweeps. Protective clothing and frequent bathing stopped it.

Top 10 ways to prevent cancer:

1) No smoking tobacco (lung cancer)

2) No chewing tobacco (mouth cancer)

3) Avoid exposure to radiation (skin cancer)

Sunlight, X-rays, radon gas

4) Avoid work related chemical exposure (various cancers)

Artists should be careful with heavy metal pigments. Aerosol products, solvents and paints should be used in well-ventilated areas. Brake linings contain asbestos therefore wear a dust mask if you do your own brake jobs.

5) Eat fewer fatty and salt-cured foods

Low fat diet individuals have reduced rates of colon cancer, breast and prostate cancer. Japanese individuals in U.S. have higher incidence of these cancers compared to their Japanese relatives.

Hot dogs, bacon, bologna and salt-cured meats produce nitrosamines when cooked which cause cancer.

Barbecuing meat also produces cancer-causing compounds.

6) Don’t drink alcohol heavily (more than 2 drinks a day)

Heavy alcohol use is linked to liver, stomach, bladder cancer

7) Do not eat moldy foods

Cheese made from mold like blue cheese are fine. If grains and nuts show mold growth, throw them out.

8) Eat more fruits, vegetables and grains

These are linked to reduction in cancers of the digestive tract like stomach and colon cancer.

9) Use caution in sexual contacts

Cervical cancer increases in women with a human papilloma virus (HPV).  Since HPV is the most important risk factor in cervical cancer, an HPV vaccine has been developed and is recommended for girls of 11-12 (i.e., before they are sexually active).

10) Avoid obesity (various cancers)

9. Regulation of herbal medicine by the U.S. government

Regulated by the Food and Drug Administration (FDA) of the U.S. government.

Companies spend millions of dollars for clinical trials and it may take a number of years to go through the approval process. Tests are often stopped if results are promising. Example: Taxol is a drug used to treat ovarian and breast cancer. A study on Taxol was stopped because results were so good. It was considered ethically improper to continue giving one group a placebo when the drug was working so well.

Prescription drugs can be quite dangerous even if used properly.  Some estimates are that 100,000 people in the U.S. dies every year from adverse reactions to prescription drugs. See "Incidence of adverse drug reactions."

Herbal medicines are regulated based on the 1994 Dietary Supplement Health and Education Act.  Herbal medicines are classified as dietary supplements. They fit into the same category as vitamins and minerals. See the FDA guide to dietary supplements.They are NOT required to prove their safety. They are also NOT allowed to make health claims that their product works to treat or prevent disease, but they can claim they help general wellness, function and nutrition. For example, ginkgo biloba can state it is beneficial to mental health but NOT that it will help with Alzheimer’s.

Ephedra is the first herbal drug to be taken off the market and banned by the FDA because of adverse reactions. See "Ephedra Ban: No shortage of reasons".

10. Prescription vs. Herbal remedies

11. Coevolution

Coevolution explains why herbal remedies have >1 active ingredient.

Example:

Sunflowers have 70 defensive compounds against insects.

Sunflower ancestorà all sunflowers eaten except those with compound A

New herbivore eats compound A so all sunflowers eaten except those with A and B.

12.  Psychoactive plants (chapter 20)

Psychoactive plants alter mood or behavior.  They effect the central nervous system by stimulating receptors on nerve cells.  You can read more about psychoactive plants in Chapter 20 and on the web site www.thepepproject.net     While it may be necessary to register at this web site, its use is free.  Unit 5 of the PEP project focuses on "Why plants make drugs for humans." 

Clay tablets 6,000 years old from Sumeria in the ancient middle East refer to Opium as the "joy plant".  This suggests the use of psychoactive plants has been around for thousands of years.  Many of these plants have medicinal uses such as morphine from the opium poppy.  Morphine derivatives are the primary pain killers used in modern medicine today.  At the same time, abuse of the opium poppy seen in heroin use has significant harmful consequences both on the individual and on our society

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