Solanaceae

"Nightshade" redirects here. For other uses, see Nightshade (disambiguation).

Solanaceae
A flowering Brugmansia x insignis from the US Botanic Garden
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Solanales
Family:	Solanaceae Juss.
Genera
Acnistus Alona Anisodus Anthocercis Atropa (deadly nightshade) Browallia Brugmansia (angel's trumpet) Brunfelsia Calibrachoa Capsicum (peppers) Cestrum Chamaesaracha Combera Crenidium Cuatresia Cyphanthera Cyphomandra Datura (jimsonweed) Duboisia Fabiana Hyoscyamus (henbane) Iochroma Juanulloa Lycianthes Lycium (boxthorn) Mandragora (mandrake) Mellissia (St. Elena boxwood) Methysticodendron Nicandra Nicotiana (tobacco) Nierembergia or cupflower Nolana Petunia Physalis (cape gooseberry, ground-cherry, tomatillo) Przewalskia Quincula Salpichroa Salpiglossis Saracha Schizanthus Schwenckia Scopolia Sessea Solandra Solanum (tomato, potato, eggplant) Streptosolen Trianaea Vestia Withania

The Solanaceae is a family of flowering plants, many of which are edible, while others are poisonous (some have both edible and toxic parts). The name of the family comes from the Latin Solanum "the nightshade plant", but the further etymology of that word is unclear. Most likely, the name comes from the perceived resemblance that some of the flowers bear to the sun and its rays, and in fact a species of Solanum (Solanum nigrum) is known as the sunberry. Alternatively, it has been suggested the name originates from the Latin verb solari, meaning "to soothe". This presumably refers to alleged soothing pharmacological properties of some of the psychoactive species of the family.

The family is also informally known as the nightshade or potato family. The family includes the Datura or Jimson weed, eggplant, mandrake, deadly nightshade or belladonna, capsicum (paprika, chili pepper), potato, tobacco, tomato, and petunia.

The Solanaceae family is characteristically ethnobotanical, that is, extensively utilized by humans. It is an important source of food, spice and medicine. However, Solanaceae species are often rich in alkaloids whose toxicity to humans and animals ranges from mildly irritating to fatal in small quantities.

Flowers are typically conical or funnel in shape, with five petals, usually fused. The leaves are alternate, often with a hairy or clammy surface. Solanaceous plants produce a fruit that is either a berry, as in the case of the tomato or wolfberry, or is dehiscent capsule (breaks open upon drying, or dehiscing, releasing the seeds) as in the case of Datura. The seeds are usually round and flat, being 2-4 millimeters in diameter. The stamens are usually present in multiples of four (most commonly four or eight). The ovaries are superior. The hypogynus gynoecium is a syncarp located obliquely in relation to the median.

Alkaloids

The Solanaceae are known for possessing a diverse range of alkaloids. As far as humans are concerned, these alkaloids can be desirable, toxic, or both, though they presumably evolved because they reduce the tendency of animals to eat the plants.

One of the most important groups of these compounds is called the tropane alkaloids. The term "tropane" comes from a genus in which they are found, Atropa (the belladonna genus). The belladonna genus is so named after the Greek Fate, Atropos, who cut the thread of life. This nomenclature betrays the toxicity and lethality that has long been known to be characteristic of these compounds.

Tropane alkaloids are also found in the Datura, Mandragora, and Brugmansia genera, as well as many others in the Solanaceae family. Chemically, the molecules of these compounds have a characteristic bicyclic structure and include atropine, scopolamine, and hyoscyamine. Pharmacologically, they are the most powerful known anticholinergics in existence, meaning they inhibit the neurological signals transmitted by the endogenous neurotransmitter, acetylcholine. Symptoms of overdose may include mouth dryness, dilated pupils, ataxia, urinary retention, hallucinations, convulsions, coma, and death.

Despite the extreme toxicity of the tropanes, they are important drugs when administered in appropriate (and extremely small) dosages. They can reverse cholinergic poisoning, which can be caused by overexposure to pesticides and chemical warfare agents such as sarin and VX. More commonly, they can halt many types of allergic reactions. Scopolamine, a commonly used ophthamological agent, dilates the pupils and thus facilitates examination of the interior of the eye. They can also be used as antiemetics in people prone to motion sickness or receiving chemotherapy. Atropine has a stimulant effect on the central nervous system and heart, whereas scopolamine has a sedative effect.

A famous alkaloid from the Solanaceae family is nicotine. Like the tropanes, its pharmacology acts on cholinergic neurons, but with the opposite effect (it is an agonist as opposed to an antagonist). It has a higher specificity for nicotinic acetylcholine receptors than other ACh proteins. Its effects are well known. Nicotine occurs naturally in the Nicotiana or Tobacco genus.

Another class of toxic substances found in this family are the glycoalkaloids, for example solanine which has occasionally been responsible for poisonings, in people who ate berries from species such as Solanum nigrum or Solanum dulcamara, or spoiled potatoes.

Nutritional importance

The most important species of this family for the global diet is the potato or Solanum tuberosum, whose carbohydrate-rich tubers have been a staple food in many times and places, and which is one of the most grown crops today. In many genera, the fruits are the desirable item, for example, tomatoes, tomatillos, eggplants, uchuva, and peppers.

Some people experience sensitivity or allergy-like symptoms in response to nightshade plants.

External links

• Solanaceae in Topwalks
• SOL Genomics Network
• Solanaceae Network - pictures of plants
• Solanaceae Source - A worldwide taxonomic monograph of all species in the genus Solanum.
• Solanaceae in L. Watson and M.J. Dallwitz (1992 onwards). The families of flowering plants: descriptions, illustrations, identification, information retrieval. http://delta-intkey.com
• Solanaceae in USDA Plants Database.
• http://personal.denison.edu/~kuhlman/WOL/plants.html
• Family Solanaceae Flowers in Israel

See also

• List of plants poisonous to equines

Additional reading

D'Arcy, William G. (1986). Solanacea. Columbia University Press. ISBN 0-231-05780-6.

Radford, Albert E. (1986). Fundamentals of Plant Systematics. Harper & Row, Publishers, Inc. ISBN 0-06-045305-2.