|
MELANTHIACEAE(Bunchflower family)
Referred to as the Melanthaceae in some older publications, this family of about 120 species in 21 genera comprises plants that were until recently considered to belong to the Liliaceae. They are perennial rhizomatous herbs found in the northern hemisphere and in South America (Mabberley 1997). Many are to be found in cultivation as ornamentals, for example species of Aletris L., Chamaelirium Willd., Chionographis Maxim., Helonias L. (including Heloniopsis A.Gray), Melanthium L., Narthecium Huds., Stenanthium Kunth, Tofieldia Huds., Veratrum L., Xerophyllum Michx., and Zigadenus Michx. Medicinal and insecticidal activities have been documented for a number of species. However, the toxicity of many of these plants to humans severely limits their use. The more recently discovered teratogenicity of alkaloids present in these plants – see, for example, Keeler (1975) and Gaffield & Keeler (1994) – adds a further dimension to the toxicity profile. [Summary yet to be added] A biliary occlusive photosensitivity disorder of sheep in Great Britain and Western Europe, which is known as alveld, is caused by ingestion of bog asphodel (Videm Abdelkader et al. 1984, Wisløff et al. 2002). von Reis Altschul (1973) found an herbarium note stating that the roots of this Mexican plant are employed for killing maggots in wounds, either powdered and applied or decocted to make a wash.
The seeds of this Mexican species provide the crude drug known as Sabadilla, otherwise known as Semina Sabadillae Mexicanae. Felter & Lloyd (1898) noted that although at one time used in medicine as a vermifuge and to destroy vermin in the hair, its dangerous drastic and irritating properties have caused it to be dismissed from practice. Interestingly, Sabadilla remained official in the British Pharmaceutical Codex until 1934. Pereira (1842) described the toxicity thus: "Externally, the powder of the seeds has been used to destroy pediculi. But it cannot be applied with safety to children, and especially when the skin is broken. … an infant whose nurse had sprinkled the powder in its hair, died in convulsions. … [a young man] was rendered temporarily insane by the application of powder of cebadilla to the head. … [the powder] excites violent sneezing and discharge from the nostrils. Rubbed on the skin, the tincture causes a stinging sensation similar to that produced by veratria. After its use for some days, a slight eruption appears on the skin." Veratria is an alkaloidal mixture, otherwise known as veratrine, which may be isolated from cebadilla seeds (Todd 1967), to which the toxic properties described above have been ascribed. The 15-20 species of Veratrum are natives of northern temperate regions. Few genera illustrate more impressively the futility of employing popular plant names in scientific writing. The popular name hellebore is applied to at least two Veratrum species and is also applied to botanically unrelated Helleborus L. species (fam. Ranunculaceae). In the American West the name skunk cabbage is applied to Veratrum californicum T.Durand; in the American East, skunk cabbage is applied to the botanically unrelated aroid Symplocarpus foetidus Salisb. ex W.P.C.Barton (fam. Araceae). According to Pammel (1911), all species are irritant.
This Eurasian species is almost indistinguishable from the North American species Veratrum viride Aiton (Trease & Evans 1966). Its rhizome is the source of White Hellebore Powder, which has in the past been used as an insecticide (see, for example, Piper 1922). The crude drug Rhizoma Veratri, otherwise known as Radix Hellebori Albi, is derived from this species (Pereira 1842, Felter & Lloyd 1898). Standardised preparations of the alkaloids — protoveratrines — from the rhizome were at one time used to treat hypertension (Todd 1967, Claus et al. 1970). "White hellebore is a violent irritant poison, occasioning, when snuffed up into the nostrils, severe coryza. At present it is rarely used, except in the form of decoction or ointment, as an external application to kill lice, and cure the itch, pruritis [sic], and some other cutaneous affections; but, used thus, it is not always free from danger." (Felter & Lloyd 1898). Pereira (1842) describes similar uses, noting also that when placed in contact with the skin it is an energetic irritant. He also notes that the common name itch-root refers to the activity of the plant against scabies and tinea capitis.
This species is the source of cyclopamine, a teratogenic alkaloid that causes cyclopian and other deformities in foetuses of animals that have grazed on the plant during gestation (Keeler 1975, Gaffield & Keeler 1994). Tas & Avci (2004) reported that topically applied cyclopamine cleared plaque and guttate forms of psoriasis in 3–4 days. In traditional Chinese medicine, the rhizome — known as xing an li lu — is made into a dressing for boils and skin diseases. An aqueous extract is used to kill maggots or insects (Perry & Metzger 1980).
Referring to Veratrum puberulum, Perry & Metzger (1980) note that in Chinese traditional medicine, the rhizome — known as mao ye li lu — is made into a dressing for boils and skin diseases, and that an aqueous extract is used to kill maggots or insects.
In traditional Chinese medicine, the rhizome — known as mao sui li lu — is made into a dressing for boils and skin diseases. An aqueous extract is used to kill maggots or insects (Perry & Metzger 1980).
In traditional Chinese medicine, the rhizome — known as li lu — is made into a dressing for boils and skin diseases (Perry & Metzger 1980). An aqueous extract is used to kill maggots or insects (Perry & Metzger 1980, Huang 1993). The traditional use of a decoction of the roots or leaves of this species in Central Italy as a ovine scabicide was noted by Guarrera (1999).
In traditional Chinese medicine, the rhizome — known as gu ling li lu — is made into a dressing for boils and skin diseases. An aqueous extract is used to kill maggots or insects (Perry & Metzger 1980).
The crude drug Rhizoma (or Radix) Veratri Viridis is derived from this species (Felter & Lloyd 1898). Standardised preparations of the alkaloids from the rhizome were at one time widely used to treat hypertension (Todd 1967, Claus et al. 1970). "Applied to the skin, veratrum is rubefacient, and to the nose, excites sneezing. Veratrum has been justly praised as a remedy for erysipelas. It may be used both topically and internally. It is best adapted to that form showing tumefaction and redness, simulating ordinary inflammations. It has been successfully used, internally and locally, for the relief of poisoning by Rhus Toxicodendron. Boils, carbuncles, inflamed pimples, felons, ulcers, with heat and tumefaction, cellular inflammations, and labial herpes are well treated by painting specific veratrum upon them." (Felter & Lloyd 1898). Weber (1937), and Schwartz et al. (1957) citing Muenscher (1951), included this species in lists of irritant plants. References
|
|
url |