Catharanthus roseus

rosy periwinkle

Rosy periwinkle is one of the best examples of plant-derived medicine. Two compounds named vinblastine and vincristine have been extracted from the plant and are used to treat lymphomas and childhood leukemia, respectively. After discovery of the medicinal potential of the compounds in this plant in the late 1950s, survival of childhood leukemia jumped from 10% to over 90%.

The cancer-fighting power of this plant was first discovered when scientists were looking into the plant as a diabetes medicine, as the plant was a “folk remedy” of some repute for this condition. After analysis of the chemical makeup of the plant, a number of toxic alkaloids were discovered and tested further. Vincristine and vinblastine, in particular, were the most significant discoveries as they disrupt the division of certain cancer cells. Here's a short video clip about drug development, illustrating the journey from plant to medicine:

Over 70 other alkaloids have also been extracted from rosy periwinkle, and their potential in medicine continues to be explored. We can find clues of the potential uses for the abundance of alkaloids in the plant by looking at its many different applications in traditional medicine. In India, wasp stings are treated with sap from the leaves. In the Caribbean, the plant is used to treat high blood pressure and tuberculosis. In Surinam, leaves and flowers are boiled together to treat diabetes. In Vietnam, the plant is used to treat diabetes and malaria.

The value of plants for medicinal treatments and cures, like the ones provided by rosy periwinkle, is especially important to humans since everyone deals with illness during their lifetime and most people don’t really find it that enjoyable. Many current treatments involve compounds extracted from plants or inspired by them. The idea that there could be a plant somewhere that could provide an effective treatment or cure for a currently incurable condition is a big reason why people become advocates for conserving plant diversity; there is still so much out there to explore and discover.

As with many other powerfully medicinal plants, rosy periwinkle is toxic if ingested. Powerful compounds have both the capacity to heal and to kill, which is why dosage is so important. Plants also have variable concentrations of compounds based on their environment, the time of year, and even the time of day, so this enhances risk and underscores the value of the knowledge of indigenous peoples who have used the plants for medicine perhaps for hundreds of years.

There are many different colors and growth habits of rosy periwinkle available for the landscape. It prefers poor soils with good drainage and does quite well in hot, dry climates. We've had trouble growing the plant here in the Gardens because of its susceptibility to fungal rot, especially when young. In colder climates, rosy periwinkle makes a great annual.