Medicinal Plants

I. Introduction & Brief History of Medicinal Plant Usage

-early man (60,000 years ago)

-Pen-Ts'ao (4500 years ago) 'Chinese Hippocrates'

-Sumerian tablets (3500 years ago) First medical text

-Ebers Papyrus (3500 years ago)

-Hippocrates (460-377 BCE) Hippocratic Oath

-Dioscorides (1st century AD) De Materia Medica

Age of Herbals (1450-invention of printing press)

Doctrine of Signatures (Paracelsus 1493-1541)

William Withering (1741-1799) detailed study of herbal treatments

Friedrich Serturner (1783-1841) isolation of active chemical from plant (morphine)

~25% of prescriptions written today have plant-derived active ingredients

II. Herbal Medicine Today

China, India, Africa, South America

National Cancer Institute

Ethnobotany

Indigenous Knowledge

Terra Nova Forest Preserve

Student Research at UCA

1. Search for antimicrobials in Arkansas plants

Plants that show antimicrobial activity:

Morus rubra (Mulberry), Ulmus americana (Elm), Liquidambar styraciflua (Sweetgum), Prunus serotina (Black cherry), Rhus glabra (Sumac), Solidago canadensis (Goldenrod), Lonicera japonica (Japanese Honeysuckle), Lonicera sempervirens (Trumpet honeysuckle), Lonicera flava (Yellow honeysuckle), Lonicera fragrantissima (Fragrant or Bush honeysuckle), Monarda punctata (Beebalm)

2. Anti-tumor compounds in Sesbania exaltata (Hemp Sesbania)

III. Active Chemicals

A. Alkaloids

Fabaceae (Legumes)

Solanaceae (Nightshade)

Rubiaceae (Coffee)

Structure

-nicotine

-cocaine

B. Glycosides

• terpenes
• cyanogenic glycosides:
• in water

Cassava soak before eating

Rosaceae: amygdalin

• cardioactive glycosides (milkweed, oleander)
• saponins (yamogenin)

IV. Examples of Medicinal Plants

A. Foxglove and Heart Disease

1785 William Withering

Digitalis purpurea (foxglove)

digoxin (cardioactive glycoside)

digitoxine

B. Aspirin

Salix

1828 salicin isolated (glycoside)

~1850 salicyclic acid synthesized

1898 Felix Hoffman

1970 John Vane et al

blood platelets

prostaglandins

What does salicyclic acid do in plants?

systemic acquired resistance

C. Malaria and Fever Bark Tree

malaria

Anopheles mosquito

Plasmodium merozoites

Cinchona

quinine

chloroquine

Artemisinin

D. Ephedrine

Ephedra

pseudoephedrine

diet aide?

E. Plants and Cancer Treatments

beginning in the 1960's (National Cancer Institute plant screening program)

1. Madgascar periwinkle (Vinca rosea)

vinblastine

vincristine

microtubules and the spindle

2. Pacific Yew (Taxus brevifolia)

taxol

F. Promising Herbal Remedies

suggested student presentations on St. John's Wort and Ginkgo