An herbal remedy with a rich history in folk medicine, periwinkle is the common name for a pair of perennial flowering shrubs belonging to the dogbane (Apocynaceae) family. The herb has been used for centuries to treat a variety of ailments and was a favorite ingredient of magical charms in the Middle Ages. The purple-flowered plant was called sorcerer's violet by superstitious Europeans and was renowned for its power to dispel evil spirits. There are two main varieties: lesser periwinkle (Vinca minor), which is also called common periwinkle, and greater periwinkle (Vinca major). Lesser periwinkle originated in Spain, France, and other areas of Europe but can now be found growing in many parts of the world, while greater periwinkle is native to southern Europe. While not widely recommended for medicinal purposes today, periwinkle is sometimes used to improve brain circulation and alleviate heavy menstrual periods. Only the aboveground parts of the plant are used as a drug.
It is important to distinguish lesser and greater periwinkle from a close relative called Madagascar periwinkle. The Latin name for this herb is Catharanthus roseus, but it was formerly classified as Vinca rosea, and is still called by that name in some of the herbal literature. Another member of the dogbane family, this plant originated on the island of Madagascar but now grows in the southern United States and many other temperate regions of the world. Madagascar periwinkle has been used for centuries to treat a variety of medical problems, from diabetes and eye infections to sore throats and tumors. Modern research has indicated that Madagascar periwinkle contains dozens of alkaloids, some of which may have the ability to lower blood sugar levels and stop bleeding. Two of these alkaloids, vincristine and vinblastine, are recognized by Western medicine as potent anticancer agents. (A shaman in Madagascar who used the plants to treat tumors and cancer gave Western scientists the lead.) They are used to make important prescription drugs. Madagascar periwinkle is not widely recommended as a dietary supplement because some of the alkaloids in the plant can cause serious and potentially dangerous side effects.
General use
While not approved by the Food and Drug Administration (FDA), periwinkle has been reported to have a number of beneficial effects. Unfortunately, there is scarcely any scientific evidence to support these claims. Both forms of the herb have been used as an astringent for centuries and may be useful in alleviating excessive bleeding during menstruation, according to some herbalists. Lesser periwinkle is generally recommended for improving circulation, particularly in the brain. Greater periwinkle has been used to combat nervousness or anxiety and help reduce high blood pressure. Periwinkle is also reputed to be effective in treating diabetes, perhaps by stimulating the pancreas.
While they do not recommend periwinkle for a wide variety of ailments, some practitioners of alternative medicine claim that the herb is useful in treating certain conditions. Periwinkle has been used as an effective astringent that can be used orally or topically. It is mainly used to treat excessive menstrual bleeding but may also be a helpful choice in cases of colitis, diarrhea, bleeding gums, nosebleeds, sore throats, and mouth ulcers.
Perhaps the most intriguing dietary supplement derived from periwinkle is vinpocetine, which is made from an alkaloid chemical in lesser periwinkle called vincamine. While vinpocetine is not what most people would consider a natural remedy, since it is produced via chemical manipulation in the laboratory, it is sold in the United States as a dietary supplement. Several studies of vinpocetine suggest that it may improve brain function and memory, particularly in people affected by diseases that decrease mental capacity such as Alzheimer's disease or dementia. In a double-blind, placebo-controlled trial published in the Journal of the American Geriatrics Society in 1987, vinpocetine appeared to improve the condition of several dozen elderly patients who suffered from mental impairment due to aging. Researchers found that the 42 patients who took vinpocetine for three months performed better on several tests of mental functioning than those in the placebo group. In the study, no significant side effects were associated with vinpocetine.
Exactly how vinpocetine works is unknown. According to one theory, vinpocetine may protect brain cells from damage caused by oxygen deprivation. The apparent effectiveness of vinpocetine, which is made partly from a chemical contained in lesser periwinkle, may help to explain the herb's traditional reputation as a brain booster. It is important to remember, however, that periwinkle itself has not been proven to have the same effects as vinpocetine.
Preparations
The optimum daily dosage of periwinkle has not been established with any certainty. Readers who wish to use this herb should follow the package directions for proper usage or consult a doctor experienced in the use of alternative remedies.
The dosage of vinpocetine is generally 30 mg a day, divided into three equal doses. Taking vinpocetine with food may enhance its effectiveness by increasing the amount of drug absorbed.
Precautions
Periwinkle is not known to be harmful when taken in recommended dosages, though it is important to remember that the long-term effects of taking the herb (in any amount) have not been investigated. Periwinkle should not be used by people with low blood pressure or constipation. Due to lack of sufficient medical study, periwinkle should be used with caution in children, women who are pregnant or breast-feeding, and people with liver or kidney disease.
Taking too much periwinkle can cause a potentially dangerous drop in blood pressure (symptoms include dizziness and fainting). In case of overdose, seek emergency care.
Vinpocetine should not be combined with certain medications or dietary supplements (see below).
Side effects
Periwinkle may cause flushing and gastrointestinal problems.
When taken in recommended dosages, vinpocetine is not associated with any bothersome or significant side effects.
Interactions
Periwinkle is not known to interact adversely with any drugs or dietary supplements. Periwinkle may be combined with cranesbill and agrimony. It may also be used in conjunction with beth root for menstrual problems.
Vinpocetine should not be combined with agents that thin the blood, except under medical supervision. These include drugs such as warfarin (Coumadin) and aspirin as well as dietary supplements like ginkgo, vitamin E in high dosages, and garlic.
BOOKS
Crellin, John K. and Jane Philpott. A Reference Guide to Medicinal Plants: Herbal Medicine Past and Present. Durham, NC: Duke University Press, 1997.
ORGANIZATIONS
American Botanical Council. PO Box 144345. Austin, TX 78714-4345.
