Chemicals found only in these plants have a unique ability to keep certain kinds of cancerous cells from reproducing. Impressive as the rosy periwinkle is medically and economically, its importance doesn't end there. Conservationists also prize the rosy periwinkle because it's an excellent example of why biodiversity is important. The rosy periwinkle is native to the island of Madagascar. This island off the coast of Africa has a rapidly expanding population, and many of the native plants and animals have vanished as cities and towns overtake their habitat.
Scientists know that countless other useful compounds await discovery.
As it is, more than a quarter of all the prescriptions from pharmacies come from chemicals originally discovered in plants. Yet these materials are only a minuscule fraction of the ones that are almost certainly available. We just haven't studied them yet. In most cases, we haven't studied them yet because we don't even know they're there. Up to now, he says, we've named 1.6 million species, but this is far, far short of the total.