Chapter 3.4 The Search for New Medicines

Biodiversity and Medicine People have always studied plants for their ability to heal wounds, fight diseases, and ease pain. For ex: aspirin was made from the bark of the willow tree.

Almost half of medicine were found in plants or animals first. For ex: Madagascar rose periwinkle has produced two effective cancer treatments: one for childhood leukemia, and other one for Hodgkin’s disease.

GOAL In 1995, the American Medical Association called for the protection of Earth’s biodiversity. Their goal was to preserve the undiscovered medicines that may exists in nature.

The story of Taxol Plants in many ecosystems can produce chemicals that protect them from predators, parasites, and diseases. This ability results from the plants’ adaptations to their environment. Some protective chemicals that plants produce can be used to fight diseases in humans.

The Pacific Yew This tree grows in the temperate rain forest. It is very resistant to many diseases and insects. Scientists found that bark of the tree has crystals, called Taxol, that protects the tree.

Taxol as cancer treatment Taxol stops cancer cells from multiplying by forming tiny cages around cancer cells that prevent them from diving, growing and spreading in a body.

The supply of Taxol Because of a high demand, there is a problem with supplying of Pacific yew trees. These trees must have a bark to live. Three Pacific trees are required to produce to Taxol for one cancer patient. Today, the yew tree is no longer used to make Taxol.

Synthetic Taxol Scientists have worked many years to produce synthetic Taxol in a laboratory, and they succeeded. Now, cancer patients don’t have to worry about getting Taxol. And, yew trees are saved.

Review concepts: How are plants useful for people? Give an example.

Why is biodiversity protected by the American Medical Association?

What is Taxol? How is it benefit people?

What tree provided Taxol?

How is Taxol used nowadays?

Chapter 3.4 Assessment 1a. Why did the American Medical Association call for the protection of Earths’ biodiversity? 1b. Do you think that scientists have identified all the wild plants that may have medical uses? Why or why not? 1c. Suppose many wild plants were to become extinct within a short time. What effect might this have on medical research? Explain your answer.

2a. What adaptations of rain forest plants make them likely sources of medicines? 2b. What plant is the source of taxol, and what is the function of taxol in this plant? 2c. What is the effect of taxol on cancerous tumors? In what way is this effect similar to the function of taxol in the plant?