Kigelia africana

Kigelia africana

The sausage tree or sausagetre, cucumber tree (Kigelia Africana (Lam.) Benth., 1849) is an arboreal species belonging to the Bignoniaceae family.

Systematic –
From a systematic point of view it belongs to:
Eukaryota domain,
Kingdom Plantae,
Subkingdom Tracheobionta,
Spermatophyta Superdivision,
Division Magnoliophyta,
Class Magnoliopsida,
Subclass Asteridae,
Order Scrophulariales,
Family Bignoniaceae,
Genus Kigelia,
Species K. Africana.
The term is basionym:
– Bignonia african Lam..
The terms are synonymous:
– Bignonia africana Lam. (1785);
– Crescentia pinnata Jacq. (1789);
– Kigelia abyssinica A. Rich. (1847);
– Kigelia acutifolia Engl. ex Spreng. (1906);
– Kigelia aethiopum (Fenzl) Dandy (1956);
– Kigelia elliottii Sprague (1906);
– Kigelia elliptica Sprague (1906);
– Kigelia ikbaliae DeWild. (1904).
– Kigelia pinnata (Jacq.) DC. (1838);
– Kigelia impressa Sprague (1906);
– Kigelia spragueana Wernham (1914);
– Kigelia talbotii Hutch. & Dalziel (1931);
– Kigelia tristis A. Chev. (1920);
– Sotor aethiopiumm Fenzl (1844);
– Tanaecium pinnatum (Jacq.) Willd. (1789).

Etymology –
The term Kigelia derives from the Bantu vernacular name kigeli-kaia used for the plant in Mozambique.
The specific African epithet is related to its origin from Africa.

Geographic Distribution and Habitat –
Kigelia africana is a plant native to an area that includes much of tropical and southern Africa and precisely: Chad, Eritrea, Ethiopia, Sudan, Burundi, Cameroon, Equatorial Guinea, Rwanda, Democratic Republic of the Congo, Benin, Coast of ‘Ivory, Gambia, Ghana, Guinea, Liberia, Mali, Nigeria, Senegal, Sierra Leone, Togo Botswana, Namibia, Swaziland and South Africa.
However, it is also cultivated for ornamental purposes on all continents.
Its habitat is that of the rainforest, the savannah of Guinea and Sudan; usually in humid places, mainly in humid savannah woods, it spreads in gallery woods and along rivers in humid forests, where it is found at low altitudes in open woods and on river edges and, in any case, no higher than 3,000 metres.

Description –
Kigelia Africana is a medium-sized tree, with heights ranging between 10 and 15 (20) metres, with smooth, greyish bark and compact, rounded foliage.
The trunk is sometimes crooked, generally branches from below and can reach 80 cm in diameter.
The leaves are odd-pinnate, up to 50 cm long, they are odd-pinnate with 5-13 ovate or elliptical leaflets up to about 15 cm in length; they are leathery, rough to the touch, dark green, with prominent veins on the underside. These leaves are evergreen or deciduous, depending on the climate in which it grows.
The inflorescences are pendulous, borne on a long peduncle, up to 2 m, with large, bell-shaped flowers, with 5 petals, about 13 cm in diameter, generally red-purple in color with yellow veins on the outside.
The flowers have a rather unpleasant smell, according to some, they open in sequence and remain open for only one night and are usually pollinated by bats; when a flower is pollinated the other buds belonging to the same inflorescence usually abort and this is to avoid the presence of many fruits on the same peduncle which could not support its weight.
The fruits are woody berries, oblong-cylindrical in shape, which can reach a length of 80-100 cm with a diameter of 12 cm and a weight of up to 12 kg; they are greyish in colour.
Inside, immersed in a fibrous pulp, there are numerous hard, obovoid seeds, 1 cm long and approximately 0.7 cm wide, which remain germinable for a long time.

Cultivation –
Kigelia africana is an extremely variable, semi-deciduous plant, and is an important medicinal plant in its native range, where it is commonly collected from the wild for local use. The fruits are often sold in local markets, and more recently, the plant has become an ingredient in commercial applications to treat a number of skin conditions.
The tree is often grown or protected in and around villages in tropical Africa for medicinal purposes and to provide shade and a meeting place in villages.
Furthermore, it is also widely cultivated as an ornamental plant in the tropics of all continents.
However, breeding as an ornamental road plant is not recommended as the falling fruits weigh up to 12 kg and can cause extensive damage to people. Furthermore, it has a rather invasive root system and should not be planted near buildings.
It is a plant that grows at low to high altitudes in the tropics, where it is found up to 3,000 meters and grows in areas where the average annual rainfall is between 900 and 2,000 mm.
It is not frost hardy, but if the young plants are protected for the first 2 – 3 years from the cold winds of colder areas, they will survive.
From a pedological point of view it prefers medium-loamy soil.
It grows best in a sunny position in fertile, humus-rich and well-drained soil.
It is a relatively slow growing tree, with a growth rate of at least 1 meter/year, but is slower in colder areas.
The trees begin to flower when they are about 6 years old from seed.
The plants can flower intermittently all year round.
The tree can be successfully used for bonsai.
Propagation occurs by seed and it is recommended to immerse the seed in hot or boiling water for one minute before sowing to improve germination.
The seeds are placed in seedling trays filled with pure river sand; they are pressed into the sand until the tip is level with the sand, covered lightly with a thin layer of sand or pure compost and kept moist.
The seed usually germinates after 10 – 25 days, they also germinate best at temperatures at or slightly above 23°C.
In nature the seeds are released when the fruit rots on the ground and the plants regenerate naturally. Viability is maintained for more than 3 years in hermetic storage at room temperature. Dried seeds store well in a cool place.
Furthermore, its fruits are so hard that they must be eaten by elephants so that the seeds can be dispersed.

Customs and Traditions –
Kigelia africana is a rather variable plant, so much so that botanists have described a large number of species, but it is now believed that the genus is monospecific and that the variations are due to ecological influences, which also affect phytochemistry.
This plant is known by various names including: salami tree, sausage tree (Italian); sausage tree, sausagetre, cucumber tree (English); saucissonnier, faux baobab (French); leberwurstbaum (German); árbol de las salchichas (Spanish); árvore da salsicha (Portuguese).
This plant, in addition to being a food or having a decorative use (introduced in some gardens), is used in Africa from the pulp of its fruits to strengthen and tone the skin of the female breast (pectorals). This tree produces flavonoids. Essential oils contribute to the same effect. Its bark is known locally as an effective remedy for snake bites and toothache or stomach ache.
The Maasai also use the pulp of the fermented fruit to produce a very strong beer.
The fruits are not edible, but the seeds, poisonous when immature, have limited food use in their places of origin, roasted, in periods of famine.
The leaves locally have an important role as fodder. Plant known and used since ancient times in traditional medicine, in particular for the treatment of skin diseases, whose effectiveness is confirmed by the presence in the plant, particularly in the bark and fruits, of sterols, flavonoids and other substances with antibacterial and antifungal; Extracts of the plant are used in the modern cosmetic industry. Laboratory studies have also highlighted the presence of substances with anti-tumor properties in fruits.
Among the phytochemicals identified in plant extracts, the compound groups to which activity is most frequently attributed are naphthoquinones and iridoids.
Extracts from the bark, wood, roots and fruits have antibacterial and antifungal properties. These extracts show significant inhibitory effects in vitro against common Gram-negative and Gram-positive bacteria and against the yeast Candida albicans.
Of the naphthoquinones isolated in fruit and root extracts, kigelinone showed notable antimicrobial activity.
Iridoids and dihydroisocoumarins present in bark, fruit and root extracts can enhance the antimicrobial activity of naphthoquinones.
Other active antimicrobial compounds found in the bark are phenylpropanoids, caffeic acid, p-coumaric acid, and ferulic acid.
The plant is renowned for its anti-tumor properties and laboratory screening has confirmed in vitro anti-tumor activity.
Fruit extracts have shown significant effects against induced tumors. Fruit and bark extracts showed moderate efficacy against melanotic cell lines. The naphthoquinones lapachol and isopinnatal, present in some bark, wood, fruit and root extracts, show antineoplastic activity against melanoma cell lines. Sterols and iridoids are ubiquitous in the plant and may be a factor in activity against melanoma. The root cytotoxicity reported in the brine shrimp test was attributed to the presence of γ-sitosterol.
The fruits have demonstrated anti-inflammatory actions in vivo.
Cinnamic acid derivatives are believed to be responsible for the anticonvulsant properties for which the plant is used to prevent epileptic seizures.
The leaves and fruits contain flavonoids. A high concentration of flavonoids may be responsible for the antidiarrheal properties, augmented by antimicrobial constituents.
In contrast to the use of the plant as a laxative, preliminary studies have demonstrated a preventive effect of leaf extracts against diarrhea.
In traditional African medicine, Kigelia fruit is used to treat rheumatism, snake bites, syphilis and even the influence of evil spirits. An alcoholic drink similar to beer is also made from it. The raw fruit is poisonous and has a powerful purgative effect; to consume it it must be dried, roasted or left to ferment.
Among the various uses we remember the agroforestry ones.
The extensive root system makes the plant suitable for controlling erosion and stabilizing river banks; furthermore the tree does not compete with nearby crops.
Among other uses, it is reported that the fruit contains tannins which can also be extracted from the roots and bark of the stem.
A black dye can be obtained from the fruit and a yellow dye can be obtained from the roots.
In areas where stones, which are used to mark cooking fires, are scarce, the fruits are used to place pots on the fire as they are almost fireproof.
The husk is hollowed out, fitted with a noose and bait and used as a mousetrap.
Dolls are also made from the peels, while some make ladles and cups from the cut chaff.
The heartwood is light brown to reddish-yellow; the sapwood is white-yellow; the wood is light, soft, but strong.
It has no commercial value, but is widely used by local people where it is used for items such as fence posts (where it is believed not to rot); canoes (for this purpose they are so appreciated that in Malawi the tree had to be protected); a wide range of small parts such as tool handles, mortars, drums, boxes and stools; the wood of the branches is used for the bows; and small branches are hollowed out to make enema tubes for use on children.
Wood is used as fuel.
From an ecological point of view it is emphasized that the red flowers open at night and give off a bad smell. They are pollinated by bats who identify them by their smell and by the fact that they hang in the trees, giving the impression that they are similar to them. Their red color prevents them from being seen by insects, which are unable to perceive that wavelength.

Preparation Method –
Kigelia africana is a plant whose fruits are inedible, even when fully ripe, and are said to be purgative and toxic; furthermore the unripe fruits are poisonous.
Edible uses include the seeds which are toasted and used as food in case of famine.
The fruit is a common additive to ferment in brewing to increase potency or add flavor.
Sometimes the fruit is cooked first and the fleshy part is added to the infusion to increase its strength, or sometimes the peel is used.
It has been hypothesized that these additions lead to increased fermentation resulting in the formation of amyl alcohol and explain the severe hangovers after drunkenness.
Malawi squirrels are said to be very fond of the fruit; whether they eat the pulp and seeds is not certain, but it seems that the sap they obtain by gnawing the end of the peel makes them quite drunk.
Flower nectar is used as a source of sugar.
Medicinally, sausage tree is a widely used herbal treatment in Africa, used in the treatment of numerous ailments. The fruits are the most commonly used, although all parts of the plant have similar properties. The variety of ailments against which the plant is used includes digestive problems, fainting, anemia, sickle cell anemia, epilepsy, respiratory disorders, liver and heart disorders, and nutritional diseases such as kwashiorkor, rickets, wasting and weakness. Much modern research supports traditional uses, and the plant has become an ingredient in commercially produced applications for treating skin problems.
The plant is mainly used to remedy a wide range of skin problems.
Powders and infusions of bark, leaves, stems, twigs or fruits are used to clean and dress flesh wounds and open sores. Many dressings, topical treatments and infusions containing this species are also used for their analgesic and anti-inflammatory properties. The bark, stems, twigs, leaves and fruits are infused and taken orally, or applied topically, to relieve rheumatism, sprains, hematomas and bruises; Snake bite antidotes are made with an infusion of fruit, stems, leaves, twigs or bark, taken orally or rubbed on the bite. Infectious diseases, including leprosy, impetigo, and blood worm infestations, are all treated with this plant; skin disorders and infections, such as whitlows, cysts, acne and boils, are treated with traditional medicines containing the fruits and, less frequently, the bark; Irritated eyes are treated with drops of floral sap mixed with water.
The fruits which, as mentioned, are not edible, even when fully ripe, are said to be aphrodisiacs, intoxicating, purgative and toxic.
In particular, the fruit is used to increase the size and function of the breasts. It is given as a decoction, and also massaged onto the breasts, of girls before puberty to promote extensive development, a practice said to be demonstrated by recorded measurements.
Infusions and decoctions are applied as a wash or rub to promote weight gain in newborns. The fruit is used to increase milk flow and as a poultice to treat conditions such as mastitis and breast cancer.
The fruit and roots, along with the “male” tassel of the plantain inflorescence, are boiled together to form a female nostrum.
The fruit is also used in the treatment of many other ailments. For example, it is used to treat scrotal elephantiasis; leg edema; asthma; combined with peppers, it is used against constipation and erythema.
Externally the fruit is used in poultices to treat wounds, syphilis, ulcers, boils and rheumatism.
The powdered ash of the fruit is said to have disinfectant and healing properties similar to boric acid.
Cut into pieces, the fruits are boiled with the roots of Anthocleista sp., and the liquid is drawn by air current or enema to treat hemorrhoids and lumbago.
The bark and fruit are combined and used to heal sores and restore taste. From the powder an oily ointment is obtained to be spread on rheumatic parts and malignant tumors.
The bark is said to contain a bitter principle and tannic acid. It tastes a little bitter. It is pounded and taken internally to relieve asthma and to treat dysentery and venereal diseases. It is used, in the form of a decoction or enema, to treat dysentery and stomach and kidney disorders, but only in combination with other plants.
Similar preparations are used in steam baths to treat snake bites: this softens the wound, facilitating the action of drugs applied subsequently.
The heated bark is applied to women’s breasts to help them return to normal after weaning the infant.
The bark is joined to the bark of Mitragyna inermis; the roots of Xanthoxylum xanthoxyloides; and the seeds of Sterculia setigera to treat epilepsy. It also enters several prescriptions for the treatment of leprosy.
The root, with a bitter taste, is used as a remedy against boils, sore throats, constipation and tapeworms. Combined with other roots, it is soaked in water which is then drunk to cure syphilis.
The leaves are sometimes used to treat rheumatism, malaria, infertility, epilepsy, headaches, dysentery, stomach and kidney disorders. They can be used to prepare a general tonic to improve health and growth.
An infusion of the leaves with other leaves is used to treat an undefined venereal disease.

Guido Bissanti

Sources
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (ed.), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora d’Italia, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.

Photo source:
– https://inaturalist-open-data.s3.amazonaws.com/photos/291234159/original.jpeg

Attention: Pharmaceutical applications and food uses are indicated for informational purposes only, they do not represent in any way a medical prescription; we therefore decline any responsibility for their use for healing, aesthetic or food purposes.