Learning Objectives:

•To describe the importance and medicinal value of drugs produced by plants.

Yams are a source of steroids. The most

important yam steroid is diosgenin which can

be converted into progesterone for use in the birth-control

pills.

Colchicine is found in the autumn crocus, also known as meadow saffron. It is an anti-inflammatory used primarily

for treating gout.

Digitalin is found in foxglove plant.

It is used to treat heart failure. Foxglove extract was first

shown to be effective in 1785 by an English doctor named William Withering. However, foxglove plants were used for

centuries prior to this for treating many different

illnesses.

The use of willow bark dates back to the time of Hippocrates (400 BC) when patients were advised to chew it to reduce fever and inflammation. It continues to be used today for the treatment of pain, headache, and inflammatory conditions.

Ergotamine constricts blood vessels and is used to treat migraines. It is found in ergot, a fungus that grows

on rye plants. This drug is chemically similar to LSD, and a disorder called St. Anthony's Fire, with symptoms similar to the experience of an LSD

trip, can result from eating rye infected with ergot.

Morphine is a highly potent drug and is the principal active agent in opium. Like other opioids, e.g.heroin, morphine acts directly on the central nervous system to relieve

pain. Morphine is highly addictive.Patients on morphine often report insomnia, visual hallucinations and

nightmares.

Pseudoephedrine is a decongestant found in common cold remedies such as Sudafed.

It is found in the ephedra plant, which is also the source of the dangerous diet drug

ephedrine.

•Chamomile (Matricaria recutita) - soothes indigestion and colic, eases tension, and is good for skin irritations.

• Echinacea - boosts the immune system, and lessens the severity of colds and flu

• Lavender - calms and relaxes, eases pain and is antiseptic for cuts and bruises.

• Lemon balmLemon balm - soothes nervous tension and anxiety, promotes sleep, and is good for cold sores.

• PeppermintPeppermint - good for digestion, wind and headaches.

• RosemaryRosemary - helps memory and concentration, improves mood, sweetens breath.

• St John's WortSt John's Wort - anti-depressant and promotes skin healing

Drugs from plants

• Why do they extract the chemical from the plant – why not get patients to eat the plant?

• List the advantages and disadvantages of using medicines derived directly from plants, as opposed to synthesised drugs

Advantages:• Less additives• Active ingredient difficult to synthesise – need to work in

conjunction with others,

Disadvantages:• Difficult to control dosage• More expensive (due to extraction and purifying process)

Limited supplies

• What are the options available if supplies of a medicinal plant are limited?

Limited supplies

• Cultivating the plant in its native area• cultivating the plant in other areas• finding alternative plant sources (particularly if

these can be grown faster or more of the necessary ingredient can be harvested from them)

• synthesising the active compounds• synthesising similar compounds and testing

them for medicinal effects