Rue

Scientific Name(S): Ruta graveolens L., R. montana L. and R. bracteosa L. have also been reported to be used medicinally. Family: Rutaceae

Common Name(S): Rue, common rue, garden rue, German rue. Not to be confused with' meadow rue (Thalictrum spp.)

Botany: Rue is native to Europe but is now cultivated worldwide. It is often found growing along roadsides and in waste areas. It is an herbaceous evergreen half-shrub that grows to 2 or 3 feet tall. The leaves have three fleshy lobes and are "teardrop"-shaped. It blooms greenishyellow flowers from June to August. The flowers have a characteristically disagreeable odor. The aerial parts, which are gathered in the summer, are used. The plant is both ornamental and medicinal.

History: The leaves, other parts, and extracts of rue have been used for hundreds of years as insect repellents and, in folk medicine, as antispasmodics, sedatives and stimulants for the onset of menses. Depending on the local culture, rue extracts have been used as abortifacients.

In New Mexico, rue is used traditionally as a tisane for ailments such as stiff neck, dizziness, headache, tightness in the stomach and inner ear problems. The oil has a strong bitter taste and was once used for the treatment of intestinal worms.

Roman naturalist Pliny the Elder (23 to 79 AD) mentions 84 remedies containing rue. In ancient Greece and Egypt, aside from its use as an abortifacient, rue was also used to strengthen eyesight.

Uses of Rue:

Rue extract is useful as a potential potassium channel blocker. It has been used to treat many neuromuscular problems and to stimulate menstruation onset. Because rue has an antispasmodic effect at relatively small dose, take with caution, if at all.

Side Effects of Rue:

Rue extracts are found to be mutagenic and furocoumains have been associated with photosensitization. If ingested, the rue oil may result in kidney damage and hepatic degeneration. Large doses can cause violent gastric pain, vomiting and systemic complications including death. Because of possible abortifacient effects, the plant should never be ingested by women of childbearing potential.

Toxicology: Because the antispasmodic effect of this plant occurs at relatively small doses, rue should only be taken with caution, if at all. The safety of the plant in pregnant women has not been established and most of the literature describing its potential abortifacient effects indicate that the plant should never be ingested by women of childbearing potential.

Extracts of rue have been found to be mutagenic in experimental mutagenicity screens, but the clinical importance of these findings has not been established.

The furocoumarins have been associated with photosensitization, resulting in skin blistering following contact and exposure to sunlight. This occurs in people who collect fresh rue and has been reported in those who rubbed fresh rue on themselves as an insect repellent. The toxicity of the dried leaves is most likely less than for fresh leaves because of the loss of volatile oil. A tincture of R. graveolens L. exhibited marked photomutagenicity of varying degrees based on different alkaloid concentrations present in the compound.

The volatile oil has an irritant quality and may result in kidney damage and hepatic degeneration if ingested.

Large doses (more than 100 ml of the.oil or about 120 g of the leaves in one dose) can cause violent gastric pain, vomiting and systemic complications including death. A single oral dose of 400 mg/kg given to guinea pigs has been reported to be fatal because of hemorrhages of the adrenal gland, liver and kidney. However, an oral daily dose of 30 mg given to human subjects for 3 months did not result in abnormal hepatic function.

Summary: Rue is an odiferous herb that has been used in traditional medicine and noted in folklore for hundreds of years. It has been used as an antispasmodic, and recent studies indicate that several of its components are similar to or more potent spasmolytics than papaverine in their effects on gastrointestinal and cardiac smooth muscle. The oil has been used as a folkloric abortifacient, and the plant should not be ingested, especially by pregnant women. Many compounds present in the plant possess antibacterial and antifungal properties. Rue has been used to treat intestinal worms and to repel insects. The furocoumarins contained in the plant are photosensitizers, and the topical application of the plant should be avoided. Although rue continues to be found in some herbal remedies, its use should be avoided.