| Veratrum | |
|---|---|
| Veratrum album | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Monocots |
| Order: | Liliales |
| Family: | Melanthiaceae |
| Genus: | Veratrum L. |
| Species | |
|
25 to 40; see text. |
|
Veratrum is a genus of coarse, highly poisonous perennial herbs of the Melanthiaceae family. In English they are known as the False hellebores or corn lilies. Members of Veratrum are known both in western herbalism and traditional Chinese medicine as toxic herbs to be used with great caution. It is one of the medicinals ("Li lu") cited in Chinese herbal texts as incompatible with many other common herbs because of its potentiating effects. Especially, many root (and root-shaped) herbs, particularly ginseng, san qi, and hai seng, will create and or exacerbate a toxic effect[1].
Veratrum species are used as food plants by the larvae of some Lepidoptera species including Setaceous Hebrew Character.
Birth defects in livestock grazing on Veratrum californicum (native to the western United States) led to the study of cyclopamine and jervine which are important in animal developmental biology including cancer treatment.
Contents |
Veratrum is found in many areas of the temperate Northern Hemisphere.[2]
Widely distributed in montane habitats throughout North America, Veratrum species prefer full sunlight and deep, wet soils, and are common in wet mountain meadows, swamps, and near streambanks. Veratrum species occur from Alaska south into the mountains of California, and are widely distributed throughout the Rocky Mountains. Veratrum is very abundant in Eastern North America from Quebec southward through the Appalachians into North Carolina. Thirteen species are found in China.[2]
Veratrum species contain highly toxic steroidal alkaloids (e.g. veratridine) that activate sodium ion channels and cause rapid cardiac failure and death if ingested.[3] All parts of the plant are poisonous, with the root and rhizomes being the most poisonous.[3] Symptoms typically occur between 30 minutes and 4 hours after ingestion and include nausea and vomiting, abdominal pain, numbness, headache, sweating, muscle weakness, bradycardia, hypotension, cardiac arrhythmia, and seizures.[3] Treatment for poisoning includes gastrointestinal decontamination with activated charcoal followed by supportive care including antiemetics for persistent nausea and vomiting, along with atropine for treatment of bradycardia and fluid replacement and vasopressors for the treatment of hypotension.[3]
Native Americans used the juice pressed from the roots of this plant to poison arrows before combat. The dried powdered root of this plant was also used as an insecticide.[4] Western American Indian tribes have a long history of using this plant medicinally, and combined minute amounts of the winter-harvested root of this plant with Salvia dorii to potentiate its effects and reduce the toxicity of the herb. The plants' teratogenic properties and ability to induce severe birth defects were well known to Native Americans.[4]
Veratrum species produce highly toxic steroidal alkaloids only when the plants are in active growth. During the winter months, when the plant enters its dormant stage, it degrades and metabolizes most of its toxic alkaloids. Herbalists and Native Americans who used this plant for medicinal purposes harvested the roots during the winter months when the levels of toxic constituents were at their lowest.
The roots of V. nigrum and V. schindleri have been used in Chinese herbalism (where plants of this genus are known as "li lu" (藜蘆). Li lu is used internally as a powerful emetic of last resort, and topically to kill external parasites, treat tinea and scabies, and stop itching. [1]. Some herbalists refuse to prescribe li lu internally, citing the extreme difficulty in preparing a safe and effective dosage, and that death has occurred at a dosage of 0.6 grams.[1].
During the 1930s Veratrum extracts were investigated in the treatment of high blood pressure in humans. Patients treated often suffered side effects due to the narrow therapeutic index of these products. Due to their toxicity and the availability of other less toxic drugs, use of Veratrum as a treatment for high blood pressure in humans was discontinued.[3]
Veratrum species are an important source of life-saving medications used in modern medical preparations which lower blood pressure, slow the heartbeat, and are used for cancer treatment. Cyclopamine derived from Veratrum species is a potent teratogen that is an effective treatment for several deadly and malignant cancers, including basal cell carcinoma, medulloblastoma, rhabdomyosarcoma, glioblastoma, and multiple myeloma.[5]
The genus contains about 25 to 40 species.[2][6] The number of species is affected by whether certain groups of species are treated as one species or several (especially in four groups which include, respectively, Veratrum album, Veratrum nigrum, Veratrum maackii, and Veratrum viride).[6] It also depends on whether the closely related genus Melanthium is included in Veratrum and, if considered separate, where the line is drawn between the two genera.[6]