Catharanthus roseus (Vinca rosa), a member of the dogbane family, is a common groundcover plant. It is native to Madagascar and other parts of Africa and has more than 400 known alkaloids. Some are used by the pharmaceutical industry for the treatment of childhood leukemia, Hodgkin's disease, testicular cancer and cancerous tumors. Taken as a daily supplement, it improve the blood supply to the brain, increases oxygen and glucose, helps prevent abnormal blood coagulation.
Extracts of Vinca rosa have significant anticancer activity against numerous cell types. A decoction of all parts of Vinca rosa is well known as an oral hypoglycemic agent The decoction is also taken to treat malaria, dengue fever, diarrhea, diabetes, cancer and skin diseases. Extracts prepared from the leaves have been applied as antiseptic agents for the healing of wounds, against hemorrhage and skin rash and as a mouthwash to treat toothache. The aerial parts are also considered diaphoretic and diuretic and decoctions are taken to relieve indigestion, dyspepsia, dysentery, toothache and as a emetic, purgative, vermifuge and depurative.
In Uganda, an infusion of the leaves is taken to treat stomach ulcers. The aerial parts of the plant are also used for the extraction of the medicinal alkaloids vincristine and vinblastine. The alkaloids are prescribed in anticancer therapy.
"The direct extraction of only one ounce of vincristine requires fifteen tons of periwinkle leaves and costs well over six thousand dollars. Small quantities are so effective, however, that only ten pounds a year are employed in the United States. Eli Lilly markets vincristine by the trade name Oncovin. Vinblastine, known to the trade as Velban, is far more plentiful. Some nations, including the People's Republic of China, are augmenting the natural supply of periwinkle alkaloids by mass growing of the plants. Because of the low yield of vincristine from Catharanthus roseus, the Chinese find it necessary to process up to a quarter of a million pounds of dry leaves at a time in order to recover a reasonable yield of this alkaloid. The leaves represent only about 10 percent of the total dry weight of the plant, so the Chinese usually harvest nearly two million pounds of fresh plants at a time." (Genesis of Eden; http://www.dhushara.com/book/twelve/tw1.htm#anchor387904)
The dried root is an industrial source of ajmalicine, which increases the blood flow in the brain and peripheral parts of the body. It is used to treat the psychological and behavioral problems of senility, sensory problems (dizziness, tinnitus) cranial traumas and their neurological complications.