Module 14 The Biodiversity of Earth

Module 15 How Evolution Creates Biodiversity

Module 16 Speciation and the Pace of Evolution

Module 17 Evolution of Niches and Species Distributions

From 1918 to 1920, the world experienced a flu outbreak of unprecedented scale. Known as the Spanish flu, the disease had a devastating effect. Mortality estimates from that time vary, but somewhere between 20 million and 100 million people died worldwide, including more than 600,000 people in the United States. During the height of the outbreak, reports stated that some people in China had found the roots of a particular plant beneficial in fighting the flu. The plant (Ferula assafoetida) had a pleasant smell when cooked, but the raw sap from the roots had a foul smell that inspired the plant’s common name, the Dung of the Devil.

The Dung of the Devil story does not end in 1920. It turns out that Spanish flu was caused by an H1N1 virus that is closely related to the H1N1 virus that caused the worldwide “swine flu” outbreak of 2009–2010. Scientists in China recalled that people had used the plant to fight the Spanish flu 80 years ago, so they decided to explore its potential to combat the modern H1N1 flu virus. They found that extracts from the plant had strong antiviral properties, stronger even than those of contemporary antiviral drugs. Thus the Dung of the Devil has the potential to produce a new pharmaceutical drug to fight future H1N1 flu epidemics.

The Dung of the Devil is just one of the organisms from which humans have extracted life-saving drugs. Willow trees from temperate forests were the original source of salicylic acid, from which aspirin is derived. More recently, wild plants have provided several important medicines for treating a variety of cancers. For example, the rosy periwinkle (Catharanthus roseus), found only in the tropical forests of Madagascar, is the source of two drugs used to treat childhood leukemia and Hodgkin’s disease. The mayapple (Podophyllum peltatum), a common herb of the eastern United States, is the source of two other anticancer drugs. Many new medicines, including anti-inflammatory, antiviral, and antitumor drugs, have come from a variety of invertebrate animals that inhabit coral reefs, including sponges, corals, and sea squirts. Of the most promising current candidates for new drugs, 70 percent were first discovered in plants, animals, and microbes. Unfortunately, many species that are either known or suspected sources of drugs are being lost to deforestation, agriculture, and other human activities. At the same time, indigenous people with knowledge about medicinal uses of the natural drugs in their environment are being forced to relocate, and their knowledge may soon be lost.

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Only a small fraction of the millions of species on Earth has been screened for useful drugs. It is likely that many more medicines could be found in living organisms. The continual discovery of new drugs in organisms around the world, including the Dung of the Devil, makes yet another convincing argument for conserving Earth’s biodiversity.

Sources:
C. L. Lee et al., Influenza A (H1N1) antiviral and cytotoxic agents from Ferula assafoetida, Journal of Natural Products 72 (2009): 1568–1572; D. Newman and G. M. Cragg, Natural products as sources of new drugs over the last 25 years, Journal of Natural Products 70 (2007): 461–477.