NIGHTSHADE: CHARACTERISTICS, HABITAT AND MEDICINAL PROPERTIES - BIOLOGY - 2024

The nightshade or devil's tomato (Solanum nigrum L.) is a species of the nightshade family commonly known as nightshade. It is a subshrub native to Eurasia with white flowers with large yellow anthers and dark purple berries. It is an annual plant that inhabits disturbed places such as roadsides, vacant lots, or behaves as a weed in various crops.

Solanum nigrum is part of a complex of species of about 5 taxa distributed between Africa, Europe and America. This complex exhibits wide genetic variability, including diploids and polyploids.

Auckland Museum

The species contains alkaloids from the solanine group that have both toxic and medicinal properties. Among its medicinal properties, it stands out that it alleviates the symptoms of the herpes zoster virus, which causes "shingles".

It is also an effective treatment against inflamed joints, gastric and ophthalmological problems, among other aspects. Some scientific studies indicate that it has beneficial properties against certain types of cancer and produces antioxidants.

Due to the presence of solanines, its raw consumption can cause poisoning that can lead to death. When this occurs, intravenous physostigmine or eserine can be used as an antidote.

characteristics

The species is characterized by being an annual or multi-year plant that blooms almost all year round. It is known by a great diversity of common names, such as devil's tomato, black tomato, being more frequently mentioned as nightshade.

Morphological description

Solanum nigrum is a subshrub (woody base) 30 to 100 cm high, with erect or somewhat curved stems, pubescent and without thorns. With petiolate, broad-ovate leaves with acuminate apex, with entire or sparsely serrated edge towards the lower half.

The inflorescences are glomeruli (arranged very tightly in a globose shape) with three to twelve flowers. The flowers are small, with a peduncle and a calyx with five apple green sepals.

The corolla is rotatable (wheel-shaped) with five white petals. The stamens have large, deep yellow anthers that are connivent (join together to form a prominent cone).

The gynoecium (female part) is made up of a super ovary with five carpels that have numerous ovules.

The fruits of Solanum nigrum are small, spherical berries. These berries are initially green in color, but when ripe they turn dark purple or black.

The calyx persists at the base of the fruit, as occurs in many nightshades (example: tomato). The seeds are kidney-shaped (kidney-shaped) with a yellow-orange color.

Nightshade potentialities

In addition to its medicinal properties, Solanum nigrum has multiple potentialities of use, among which are:

Food

Although the solanine contained in the leaves and fruits is toxic to humans, cooking denatures it. Thus, in Africa it is used as food for humans and animals.

Similarly, the cooked ripe fruits are used to prepare jams.

For genetic improvement

Nightshade is a potential source for the genetic improvement of potatoes and eggplant. The genes that the species possesses have shown usefulness in providing resistance against Phytophtora infects (pathogenic fungus).

As an insecticide

The species belongs to the genus Solanum L. more than the Solanaceae family, with more than 1,400 species worldwide.

Solanum nigrum was described by the Swedish botanist Carlos Linnaeus in 1753 in his famous work Species Plantarum. The epithet nigrum refers to the almost black color of its fruits.

Two subspecies are recognized for the species which are Solanum nigrum subspecies nigrum and Solanum nigrum subspecies schultesii (Opiz) Wessely.

The nightshade is part of the Moreloid group made up of about 76 species within the Solanum section.

In the Solanum section the complex «Solanum nigrum« is located, which is formed by species that are very similar to each other, so it is difficult to distinguish them.

For a long time, the species Solanum americanum Mill. And Solanum nigrum were considered the same species within the complex.

However, various studies have shown that they are two different species, differing in the number of chromosomes, chemical composition and molecular sequences.

Thus, Solanum americanum is a diploid species with 24 chromosomes, while Solanum nigrum is of polyploid origin with 72 chromosomes.

Solanum nigrum is probably considered to be a hybrid between different unidentified Solanum species.

Molecular and chemical complex studies indicate that Solanum nigrum is more closely related to Solanum scabrum and Solanum villosum than to Solanum americanum.

Habitat and distribution

Nightshade is a plant native to Eurasia that has spread to Africa, Australia, and North America. It is distributed from sea level to 3,048 meters high.

Its natural habitat is not known, since it is a plant adapted to live in environments intervened by humans.

Currently, it is common to find it as a weed in crops, at the edge of roads or in vacant lots.

Medicinal properties

S. nigrum is widely used in traditional medicine in various parts of the world, especially India, China, and Africa. The parts of the plant most used for medicinal purposes are the leaves and fruits.

Due to its use in folk medicine, various scientific investigations have been carried out to verify its therapeutic effects. Among some pathologies for which it has shown positive effects, we have:

Shingles virus or herpes zoster

In traditional medicine, extracts of the fruits and leaves of nightshade are used to alleviate the symptoms of the disease known as "shingles" or herpes zoster.

This is the same virus that causes chickenpox and affects nerve cells causing hypersensitivity in the affected area.

Anti-inflammatory and hematoprotective

Solanum nigrum leaves are used as a poultice for their anti-inflammatory properties. For this reason, they have been used with positive results in the treatment of the symptoms of rheumatic diseases.

It has been proven in laboratory tests that the extracts obtained from the plant have positive effects in the treatment of kidney ailments. Its hemoprotective capacity was already recognized by traditional Chinese medicine.

Gastritis

In South India, Solanum nigrum extract is used for the treatment of gastric ulcers, gastritis and other gastric problems.

Antitussive and antibacterial

In folk medicine, the decoction of berries and flowers is used as an effective cough syrup and expectorant. Another use of the plant is for treating bronchitis and tuberculosis.

Scientific studies have shown that the ethanolic extracts of the dried fruit of nightshade have significant bactericidal activity. Its effect on gram-negative and gram-positive bacteria has been proven.

Among the bacteria that have been shown to be susceptible to S. nigrum extracts we have Xanthomonas campestris, which is phytopathogenic, and Aeromonas hydrophila.

Nightshade also has a bactericidal effect against the pathogenic bacteria Bacillus subtilis, Escherichia coli, Klebsiella pneumonia and Pseudomonas aeruginosa.

Anticancer

Various researches show an inhibitory effect of ethyl extracts from Solanum nigrum leaves and berries on the growth of cancer cells.

Both the crude extracts and the isolated components of Solanum. nigrum prevent cell proliferation in various cancer lines. Specifically, the antineoplastic activity of these extracts against Sarcoma 180 in mice has been verified.

Similarly, the extracts of nightshade have been effective against tumor cells in different types of cancer. Among these we have the liver (HepG2), colon (HT29 and HCT-116), breast (MCF-7) and cervical (U1424,25 and HeLa27).

The raw extract is usually prepared from dried berries, but it can also be prepared from the whole plant.

Diabetes

Studies carried out in India have shown the antidiabetic effect of ethanolic extracts of Solanun nigrum leaves. As noted, the compounds present in nightshade have a significant anti-hyperglycemic effect.

Antioxidant

Recent research has shown that Solanum nigrum water extract contains several polyphenolic compounds with antioxidant activity in vitro.

These compounds include gallic acid, catechin, caffeic acid, epicatechin, rutin, and naringenin.

Antioxidants prevent damage to DNA and cell membranes caused by free radicals generated by metabolism. The uncontrolled production of free radicals is one of the causes of various neurodegenerative diseases.

Other medicinal uses

The usefulness of the extract of leaves and fruits of Solanum nigrum has also been indicated for the treatment of ophthalmological problems. In the same way, before diarrhea and dermatological problems.

Contraindications

Because it is a highly toxic plant, special care must be taken in its use as a medicinal plant. Raw extracts should not be administered orally, only cooked. Cooking denatures the toxic alkaloids.

Cases of allergy to some of the compounds that the plant has when used in topical applications can occur.

Toxicity

Solanum nigrum has a high content of solanine, a glycoalkaloid, especially abundant in immature fruits. Due to this compound, the ingestion of raw parts of the plant is toxic.

This alkaloid produces an effect similar to atropine (atropine symptoms), a compound present in other nightshades such as belladonna. Additionally, nightshade also contains saponins that can cause hemolysis.

Symptoms

Mild Solanum nigrum poisoning causes burning mouth, stomach pain, dizziness, vomiting, and fever.

In severe cases, tachycardia, dry mouth, hallucinations, seizures and paralysis are observed, and death can be caused by cardiorespiratory arrest.

Treatment

In case of poisoning, gastric lavage should be performed and activated charcoal administered. If atropinic symptoms appear, physostigmine or eserine is used as a specific antidote via the intravenous route.

References

1. Dasgupta N, SP Muthukumar and PS Murthy (2016). Solanum nigrum Leaf: Natural Food Against Diabetes and its Bioactive Compounds. Research Journal of Medicinal Plants, 10: 181-193.
2. Dehmer KJ and K Hammer (2004). Taxonomic status and geographic provenance of germplasm accessions in the Solanum nigrum L. complex: AFLP data. Genetic Resources and Crop Evolution 51: 551–558.
3. Edmonds JM and JA Chweya (1997). Blake nightshades Solanum nigrum L. and related species. International Plant Genetic Resources Institute, Rome, Italy. 113 p.
4. Hameed IH, MR Calixto-Cotos and MY Hadi (2017). Solanum nigrum L. Antimicrobial, Antioxidant properties, Hepatoprotective effects and Analysis of Bioactive Natural Compounds. Research J. Pharm. and Tech. 10 (11): 4063-4068.
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6. Rani YS, VJ Reddy, SJ Basha, M Koshma, G. Hanumanthu and P. Swaroopa (2017). A Review on Solanum nigrum. World Journal of Pharmacy and Pharmaceutical Sciences. 6 (12): 293-303.
7. Rawani A, A Ghosh and G Chandra (2010). Mosquito larvicidal activities of Solanum nigrum L. leaf extract against Culex quinquefasciatus Say. Parasitol Res (2010) 107 (5): 1235-1240.
8. Särkinen T, GE Barboza and S Knapp (2015). True Black nightshades: Phylogeny and delimitation of the Morelloid clade of Solanum. Taxon 64 (5): 945–958