Solanaceae

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Template:Redirect {{Taxobox | color = lightgreen | name = Solanaceae | image = brugmansia_lg.jpg | image_width = 320px | image_caption = A flowering Brugmansia x insignis
from the US Botanic Garden | regnum = Plantae | divisio = Magnoliophyta | classis = Magnoliopsida | ordo = Solanales | familia = Solanaceae | familia_authority = Juss. | subdivision_ranks = Genera | subdivision = Acnistus
Atropa (deadly nightshade)
Brugmansia (angel's trumpet)
Calibrachoa
Capsicum (chile peppers)
Cestrum
Chamaesaracha
Combera
Crenidium
Cuatresia
Cyphanthera
Cyphomandra
Datura (jimsonweed)
Hyoscyamus (henbane)
Iochroma
Lycium (boxthorn)
Lycopersicon (tomato)
Mandragora (mandrake)
Nicandra
Nicotiana (tobacco)
Nolana
Petunia
Physalis (tomatillo)
Scopolia
Solandra
Solanum (potato, eggplant)
Streptosolen }} Template:Wikispecies

The Solanaceae is a family of flowering plants, many of which are edible, while others are considered poisonous. The name of the family comes from the Latin Solanum "the nightshade plant", but the further etymology of that word is unclear; it has been suggested it originates from the Latin verb "solari", meaning "soothing". This would presumably refer to alleged soothing pharmacological properties of some of the psychoactive species found in the family. It is more likely, however, that 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. 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, chile 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 alkaloidal glucosides that can range in their toxicity to humans and animals from mildly irritating to fatal in small quantities.

Flowers are typically conical or funnelform 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 a dehiscent (breaks open upon drying, or dehiscing, releasing the seeds) capsule as in the case of Datura and chile peppers. 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 inferior. The hypogynus gynoecium is a syncarp located obliquely in relation to the median.

1 Synonyms and common names
2 Alkaloids
3 Nutritional importance
4 External links
5 Additional Reading

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Synonyms and common names

Nightshade is any member of the genus Solanum, of which the potato (S. tuberosum), tomato (S. lycopersicum) and eggplant (S. melongena) are part. "Shade" does not refer to the blockage of light, but actually descends from the German word "schade", meaning destruction or damage (attributed to the toxic/fatal effects characteristic of many Solanaceae species). The name Nightshade, or informally, potato, is also extended to the family Solanaceae.

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Alkaloids

The Solanaceae are known for possessing a diverse range of alkaloidal glucosides, or simply alkaloids. These nitrogenous chemicals are thought to have evolved for the purpose of discouraging animals from herbivory. As far as humans are concerned, these alkaloids can be desirable, toxic, or both.

One of the most important groups of these compounds are 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 poisoning 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 is a commonly used opthamalic agent for dilating the pupils to facilitate exploration 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.

Cocaine is also considered a tropane alkaloid due to its structural similarity to the aforementioned compounds. Its pharmacology, however, is radically different, and it does not occur in the Solanaceae family.

The most 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.

Capsaicin is structurally unrelated to nicotine or the tropanes, and is found in the genus Capsicum, which includes chile peppers such as Tabasco peppers and habaneros. The compound is not appreciably toxic to animals. However, it stimulates specific pain receptors in most mammals, those which sense heat, in the oral mucosa as well as many other epithelial tissues. This causes a sensation of burning not unlike an actual heat or chemical burn. It is used in high concentration as a deterrent in pepper sprays, and sought after for many culinary dishes for its "spiciness". It is thought that the reason one would deliberately induce pain while eating is the rewarding release of endorphins it has been shown to induce. The "hotness" of capsaicin products and foods is expressed in Scoville units. A scoville unit is the factor by which the capsaicin-containing substance must be diluted to render the resulting solution imperceptible to a tester (for example, a teaspoon of a 5,000 Scoville unit hot sauce would have to be diluted with 4,999 teaspoons of a sugar water solution to render its potential to cause a sensation on the palate gone).

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Nutritional importance

The most important species of this family for the global diet is the potato or Solanum tuberosum. Although this plant is generally considered toxic, swollen parts of the roots known as tubers generally possess no toxicity, but rather a copious store of carbohydrates that both the plant and humans can use to obtain energy. However, the tubers may become toxic if allowed to sprout. Green areas on a potato indicate new growth, which may indicate the presence of chaconine and solanine, glycoalkaloid compounds that might be poisonous in quantities that could be found in an ordinary potato serving. In many genera, the fruits are the desirable item: tomatoes, tomatillos, eggplants, and peppers fall into this category. Some people experience a sensitivity or allergy like symptoms to nightshade plants.

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