The Role of the Alkaloids of Catharanthus Roseus (l.) G.don (vinca Rosea) and Their Derivatives in Cancer Chemotherapy

The search for useful foodstuffs, dyes, medicinal agents, and other materials from plants, animals, or minerals is as old as civilization itself. It should not be surprising, therefore, to learn that all pharmacological prototypes originate from one of these three kingdoms. The alkaloids, nitrogen-containing plant bases, notwithstanding the advent of antibiotics and many valuable synthetic drugs, constitute an indispensable part of our medicinal arsenal. The manufacture of alkaloids comprises an important segment of the fine chemicals industry. Their production is steeped in tradition, and processes are usually so highly specialized that it frequently takes years to establish them on an economic basis. The author has based his pharmacognosy research on plants having reported folkloric usage and/or recorded chemical content. After conducting appropriate literature surveys, 440 plants were chosen for study. One of the plants collected and investigated was the Madagascar periwinkle, then botanically known by three names–Vinca rosea, Catharanthus roseus, and Lochnera rosea. This plant was reported to produce several desirable biological effects. Folkloric usage cited the plant as possessing properties that lowered blood sugar, thereby making it a possible source of an oral insulin substitute. It also was reported to contain alkaloids. Related Vinca species were reported to contain alkaloids and to possess both neurosedative properties and properties that lowered blood pressure. Once obtained, extracts from Catharan thus roseus elicited none of the reported biological activities. (Eventually, pure compounds were isolated which did possess the reported properties.) Submission to a cancer screening program showed a profound and reproducible activity against an experimental leukemia model designed to predict clinical activity against human leukemia. One particular alkaloid, leurocristine (vincristine), was isolated. It was effective in treating not only acute lymphocytic leukemia of childhood but a wide variety of human neoplasms as well. It has become the “common de-