Ethnopharmacology

Nina Etkin, Ph.D. collecting medicinal plants

Ethnobotanists at work in the field

• Usually the ethnobotanist must obtain permits to conduct the research from a national government - certain international protocols must be observed - if the nation in which the research is to be done was a signatory of the Rio Treaty on Biodiversity, then that nation has sovereignty over all the biodiversity within its boundaries - no plant sample that may have pharmacological properties may be removed from the nation without permission of the country

Charles Ledger – Hero or Thief?

Quinine

Cinchona officinalis – source of quinine

Ethnobotanists at work in the field

• Then the ethnobotanist must obtain permission from a village’s elders to carry out the research - because of issues of intellectual property rights, the ethnobotanist should negotiate a fair and equitable return to the local people for any commercial development of a plant used in their traditional medicine

• The ethnobotanist must meet and establish rapport with the village healers - securing and maintaining the healer’s trust is the single most important skill the ethnobotanist can have

• Ethnobotanists must develop their own personal ethnography - an understanding of the culture they are studying

Participant Observer

• living with the people under study, observing their daily life and customs, and learning about their lifestyle, foods, disease systems, and myths and legends

Jaguar Shaman and Mark Plotkin

Immersion Ethnobotany

• The extreme of involvement is immersion ethnobotany in which the researcher becomes a patient of traditional healers – e.g. seeking cure from Ayurvedic medicine

Complexities of Indigenous Healing

Indigenous healing systems can be very complex because they often incorporate at least three basic components:

1. a cosmological view of the universe that can help explain the cause, diagnosis, and treatment of disease

2. a cultural context within which health care is given

3. a repertoire of pharmaceutical substances

Traditional Chinese Medicine

Traditional Chinese Medicine

Arrow Poisons

Documented use of arrow poisons around the world

Monkshood – Aconitum ferox – source of Acontine

Monkshood – Aconitum ferox in the wild

First Ethnobotanical Chemical Isolation - Strychine

• 1805 – Leschenault describes the preparation of the Javanese dart poison Upas Tieute.

• 1809 – Magendie and Delile publish accounts of experiments on mechanism of action of the poison.

• 1819 – Pelletier and Caventou isolate strychine from other sources. Magendie uses strychine in clinical medicine.

• 1824 – Pelletier and Caventou isolate strychine from upas tieute

• 1963 – total synthesis of strychine by Woodward et al.

Strychnos nux-vomica - source of Strychine

Strychnos nux-vomica leaves and seeds

Early Report on African Arrow Poisons

• “The arrow making no noise, the herd is followed until the poison takes effect and the animal falls out. It is then patiently watched til it drops – a portion of meat round the wound is cut away, and the rest eaten. … It is possible that the Kombe may turn out a valuable remedy.”

- David Livingstone, 1861

Sir John Kirk (1832-1922) – companion of David Livingstone

Strophanthus hispidus - West African species of Kombe tree – source of strophanthin

Strophanthus flowers and seeds

Curares

Calabash curare from Strychnos guianensis – carried in gourd

Crescentia cujete – source of calabash gourd

Tube Curares – made from members of Chondrodendron and other moonseeds -

Menispermaceae

Chondrodendron tomentosum leaves and vine

Bark being scraped to start preparation of curare

Liquid dripped through shavings to extract Curare

Curare added to arrow/dart tips

Waorani man

Sandbox tree –Hura crepitans – source of huratoxin

Devil wood tree – Hura crepitans

Toxicities of several arrow poisons

Anti-tumor medicines from Arrow Poisons?

• There is a possibility that plants producing arrow poisons may also have value in producing anti-tumor medicines. Spjut and Perdue (1976) surveyed 76 species from 63 genera in 29 families and found that 46 of the species had been screened for anti-tumor activity. Of these 52% of the species and 75% of the genera had been found to have anti-tumor activity. This high anti-tumor activity probably comes from the fact that arrow poison plants almost all produce cardenolide glycosides that are cytotoxic (kill cells).