The possible existence of undiscovered drugs in rain forests has often been cited as a reason for protecting them. Because knowing the potential economic value of such drugs can help provide a basis for policy makers and international agencies to lobby for forest protection, researchers at the Yale University School of Forestry and the New York Botanical Garden quantified the value of conserving the remaining tropical forests in the face of their rapid destruction.
Analyzing net (rather than gross) revenues, the researchers estimated that each new drug is worth an average of $94 million to a private drug company and $449 million to society as a whole. To date, forty-six important drugs have already been found in tropical forests; they include vincristine and vinblastine—both isolated from the Madagascar periwinkle (Catharanthus roseus)—curare, quinine, codeine, and pilocarpine. An estimated 328 potential drugs worth $147 billion to society remain to be discovered if the forests in which they live are not destroyed first.(1)
(1) Mendelsohn, R., and M. J. Balick. Econ. Bot. 1995, 49:223–228.