Periwinkle refers to a group of plants that have been a source of potent compounds used in both folk and modern medicine. Historically, extracts from these plants were used for a variety of ailments, often leading to mixed results due to inconsistent preparation and unknown concentrations of active substances. Any consideration of its use requires a careful understanding of its specific variety and chemical components. Because periwinkle contains highly active alkaloids that can affect the human body profoundly, attempting to use it as medicine without professional guidance carries significant risks.
Identifying the Medicinal Periwinkle Varieties
The term “periwinkle” in a medicinal context primarily refers to two distinct species with vastly different applications and safety profiles. The first is Vinca minor, commonly known as Lesser Periwinkle or Common Periwinkle, which is native to Europe and yields the alkaloid vincamine. This species is most often found in traditional herbal remedies and dietary supplements marketed for cognitive support. The chemical profile of Vinca minor is associated with promoting cerebral blood flow, and its derivative, vinpocetine, is sometimes used for memory and circulation issues.
The second, far more potent species is Catharanthus roseus, known as Madagascar Periwinkle or Rosy Periwinkle. This tropical species is the source of the highly powerful vinca alkaloids used in modern chemotherapy. The chemical compounds in Catharanthus roseus are considered extremely toxic if consumed in their raw or unprocessed state. Identifying the correct plant is paramount, as confusing the two species can lead to severe poisoning.
Traditional Uses and Preparation Methods
Historically, the lesser periwinkle (Vinca minor) was the species commonly used in European folk medicine, where it was valued for its astringent and circulatory properties. Practitioners often prepared a tea or infusion by steeping the dried leaves in hot water. This preparation was traditionally consumed to treat issues like internal bleeding, including heavy menstrual flow and nosebleeds, or to act as a general tonic.
Another common preparation was an alcoholic tincture, made by soaking the fresh or dried aerial parts of the plant in a mixture of alcohol and water. Tinctures were used internally to address poor circulation and externally for their astringent qualities. For localized issues, crushed leaves of Vinca minor were sometimes applied directly to wounds as a poultice or made into an ointment with lard to treat skin complaints and bleeding piles. These historical applications were based on observation and tradition, and they are not supported by modern scientific standards for safety or efficacy.
Pharmaceutical Use of Periwinkle Alkaloids
The most significant medical contribution of the periwinkle family comes from the Madagascar Periwinkle (Catharanthus roseus), which is the source of anti-cancer compounds called vinca alkaloids. These compounds, including vinblastine and vincristine, are extracted and purified under strict laboratory conditions for pharmaceutical use. They function as anti-mitotic agents, meaning they interfere with the cell division process by binding to the protein tubulin and preventing the formation of microtubules.
This mechanism is highly effective against rapidly dividing cells, which is why these alkaloids are a mainstay in chemotherapy regimens for various cancers, such as Hodgkin’s lymphoma and childhood leukemia. The isolation process is complex and involves sophisticated chemical separation to obtain the pure alkaloid compounds in a medically safe, standardized form. The final pharmaceutical product is not a raw plant extract but a highly refined, potent drug designed for targeted action.
In a clinical setting, these vinca alkaloids are administered only intravenously and under the direct supervision of an oncologist. This method of delivery is crucial because injecting the drug directly into the vein bypasses the gastrointestinal system and allows for precise dosing and immediate medical response to potential side effects. Attempting to consume the raw plant to treat any condition is impossible and extremely hazardous due to the compound’s high toxicity and the need for exact concentration control. The therapeutic window for these drugs is very narrow, meaning the difference between an effective dose and a lethal dose is small, necessitating professional medical control.
Critical Safety Considerations and Toxicity Warnings
Both types of periwinkle contain powerful alkaloids, making them unsafe for self-medication or casual consumption. The Madagascar Periwinkle (Catharanthus roseus) is highly toxic if ingested raw and can cause severe side effects, including nausea, vomiting, nerve damage, liver damage, and even death. The potent vinca alkaloids are only safe when administered as purified, prescription-only drugs in a controlled medical environment.
Even the Lesser Periwinkle (Vinca minor), which is sometimes sold as a dietary supplement, carries significant risks. When taken orally, it can cause gastrointestinal symptoms, nerve damage, and potentially damage the kidney and liver.
Periwinkle can cause hypotension, or dangerously low blood pressure, and should be avoided by anyone already taking medications for high blood pressure, as the combination could cause blood pressure to drop too low. Individuals with existing low blood pressure or those anticipating surgery should also avoid all periwinkle products. The inherent difficulty in identifying the correct species, combined with the variable concentration of alkaloids in the plant material, makes self-dosing highly dangerous, and consultation with a healthcare provider is mandatory before considering any form of periwinkle supplement.