This species is closely related to Solanum nigrescens, differing in part by its smaller flowers and anthers, and shorter styles, indicating a selfing rather than an out-crossing mode of reproduction[]..

Common Name: American Nightshade

General Information

Solanum americanum is an annual or short-lived perennial plant, erect and widely spreading, growing up to 150 cm tall[].
The plant is often used as a vegetable - the young shoots are a very popular vegetable in Guatemala, for example[]. It is used especially in Africa, where it is often collected from the wild. It is reported as being cultivated in Sierra Leone, the lowlands of Ethiopia, Kenya, Uganda, Tanzania, Seychelles and Mauritius. It is a popular wild pot herb in Côte d’Ivoire and Cameroon, and in eastern Zimbabwe and Mozambique the leaves are also eaten as a vegetable[].

Known Hazards

The bitterness of the plant is associated with a high content of the glycoalkaloid solanine, which is found throughout the plant with the highest concentration in the unripe fruits[]. In the leaves the concentration increases with age. Solanine is poisonous and only partially soluble in water. Eating a large amount of this vegetable has been associated with diarrhoea and cardiac arrest[].
The immature fruit is poisonous[].

Botanical References

,266

Range

Possibly originally S. America, but it is widespread through the tropics and subtropics

Habitat

Rocky or dry open woods, thickets, shores or openings, often on cultivated or waste ground in eastern N. America[]. Waste places, roadsides, fields; at elevations from 100 - 2,000 metres in China[].

Properties

Weed Potential	Yes
Edibility Rating
Medicinal Rating
Habit	Annual/Perennial
Height	1.00 m
Pollinators	Self, Insects
Self-fertile	Yes
Cultivation Status	Cultivated, Wild

Cultivation Details

Solanum americanum is a plant of the tropics and subtropics, it can also be cultivated in the temperate zone. It is found at elevations up to 2,000 metres in the tropics. It grows best in areas where annual daytime temperatures are within the range 20 - 35°c, but can tolerate 15 - 40°c[]. It prefers a mean annual rainfall in the range 500 - 1,200mm, but tolerates 400 - 1,500mm[].
Prefers a sunny position but is tolerant of light shade[]. Succeeds in most soils[]. Leaf production is best in a fertile soil[].
Plants can escape from cultivation and become a weed[].
Young seedlings grow away quickly and can start flowering about two months after germination[]. The plant continues to develop new flowers for several months[].
Leaves and stem tops are collected from plants in the wild, or from fields during the rainy season. Harvesting is normally done in the early morning. The main shoot or side shoots are plucked before flowering, leaving at least 5 cm of stem for the production of new side shoots. This method allows 6 - 8 times harvests from the same plant[].
Although no accurate records are available, the yield is probably comparable to that of S. Villosum and S. Tarderemotum since the plant structure and size, and the harvesting method are comparable. The yield can therefore be estimated at 10 - 20 t/ha, but with adequate management up to 50 t/ha would be feasible[].
Some superior plants are often not harvested but are left for seed production[].
The plant is normally self-pollinating, but cross-pollination is possible by insects, mainly bees and syrphid flies[].

Edible Uses

Young shoots and leaves - cooked. Depending on the bitterness, the cooking water is sometimes changed during the cooking. This is done especially for children - elderly people often appreciate a higher degree of bitterness and will therefore leave the flowers and young fruits, whereas people who object to the bitter taste remove them. To further reduce the bitterness, the leaves are sometimes served together with cooked amaranth, either separately or as a mixture. In Uganda, the leaves are steamed and the juice is collected and used in soups, so that the nutrients are fully utilized[]. The leaves contain about 6990mg of beta carotene per 100g[]. Caution is advised, see the notes above on toxicity.

Fruit - cooked. It should be used only when fully ripe since the unripe fruit is reported to be highly toxic[, ]. The fruit is a globose berry 4 - 10mm in diameter, becoming glossy purplish black at maturity, rarely dark green, many-seeded[]. Caution is advised, see the notes above on toxicity.

In most regions, Solanum americanum fruits are considered inedible but Kipsigis children in Kenya eat the ripe fruits and also in the border region between south-eastern Zimbabwe and Mozambique the sweet fruits of local varieties are much appreciated[].

Medicinal

The plant is antispasmodic and vermifuge[]. A decoction of the whole plant is used as a blood purifier, for treating inflammation, dissipating blood stasis, and to expel worms[, ].
The plant is applied externally as a remedy for cardialgia, corroding ulcers, suppurating cancers, deep wounds, skin diseases such as dartre, and for use in poultices for treating kidney pain[].

The leaves are eaten raw to treat heart pains[, ]. The cooked leaves are said to have a heart-clearing effect[].
The juice extracted from the leaves is used to relieve chronic conjunctivitis and related inflammations[]. The pounded leaves are used to treat sores and other skin problems[].

An infusion of the leaves and stems is used to improve kidney function[].

A decoction of the root, mixed with lime juice and a pinch of salt, is drunk as a treatment for malaria[].

Other Uses

None known

Propagation

Seed - can be sown in situ, placing the seeds in pockets of up to 10 seeds at the beginning of the rainy season[]. For commercial purposes, seedlings for transplanting are produced in nurseries. The soil is loosened and enriched with decomposed manure in combination with wood ash. The seeds, in most cases mixed with sand or ash, are dispersed evenly over the soil surface or sown in rows and then mulched with grasses to prevent moisture loss from the soil[]. Transplanting may take place when the seedlings are about 15cm tall, whereby only strong plants should be selected.[]. The recommended spacing in pure stands is 30 cm × 30 cm, which could be reduced to 20 cm × 30 cm during the dry season[].
The Giriama people in Kenya, however, propagate it by stem cuttings, selecting strong stems with or without leaves at the top for a new planting.

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