Common Name: Sausage Tree

General Information

Kigelia africana is an extremely variable, semideciduous tree with a large, dense, spreading crown; it sometimes grows up to 23 metres tall but is usually smaller. The bole is sometimes crooked, it usually branches from low-down and can be 80cm in diameter[].
An important medicinal plant in its native range, where it is commonly gathered 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 range of skin complaints[, ]. The tree is often cultivated or protected in and around the villages of tropical Africa for medicinal purposes and to provide shade and a village meeting place[]. It is also widely grown as an ornamental in the tropics of all continents, producing long lax pendulous panicles of attractive, maroon-coloured, yellow-veined flowers that can be nearly 1 metre long[, ]. It is not advisable, however, to park a vehicle or to put up a tent underneath a sausage tree during the fruiting period. The 'sausages' that drop every so often weigh up to 12 kg and can cause considerable damage[].
Kigelia africana is a widespread and common species, with no known threats. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2017)[].

Known Hazards

The fruits are not edible, even when fully ripe, and are said to be purgative and toxic[]. Unripe fruits are poisonous[].

Botanical References

Range

Tropical Africa - Senegal to Sudan, south to S. Africa.

Habitat

Rain-forest; guinean and soudanian savannah; usually in damp sites; often riverain[]. Primarily in wet savannah woodland, spreading into gallery woodland and along rivers in moist forests. Low elevations in open woodland and riverine fringes[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Semi-deciduous Tree
Height	20.00 m
Growth Rate	Medium
Pollinators	Bats
Self-fertile	No
Cultivation Status	Cultivated, Ornamental, Semi-cultivated, Wild

Cultivation Details

A plant of low to higher elevations in the tropics, where it is found at elevations up to 3,000 metres[]. It is found in areas where the mean annual rainfall is in the range 900 - 2,000mm[]. It is not frost resistant, but if young plants are protected for the first 2 - 3 years from cold winds in colder areas, they will survive[].
Prefers a medium loam soil[]. Grows best in a sunny position in a fertile, humus-rich, well-drained soil[].
A very variable plant, a large number of species have been described by botanists, but it is now considered that the genus is monospecific and variations are due to ecological influences, affecting also phytochemistry[].
A relatively slow-growing tree; depending on the climate, it reaches good shade proportions in 4 - 5 years. The growth rate is at least 1 metre/year, but it is slower in colder areas[].
Trees commence flowering when they are about 6 years old from seed[].
Plants can flower intermittently all year round[]. The flowers are unpleasantly scented[].
The tree has a rather invasive root system and should not be planted close to buildings[].
The tree can be used successfully for bonsai, the thick stem being an attractive feature[].

Edible Uses

The seeds are roasted and used as a famine food[, ].

The fruit is a common additive to ferment in preparing beer to increase the potency or to add to the flavour[, ]. Sometimes the fruit is baked first and the fleshy part is added to the brew to increase strength, or sometimes it is the rind[]. These additions have been postulated as leading to increased fermentation resulting in the formation of amyl-alcohol and explain the severe hang-over after inebriation[]. Squirrels in Malawi are said to be very fond of the fruit; whether it is to eat the pulp and seeds is not certain, but it seems that sap which they get in gnawing open the end of the husk makes them quite tipsy[].

The nectar from the flowers is used as a source of sugar[].

Medicinal

Sausage Tree is a widely used herbal treatment in Africa, being used in the treatment of a great many complaints. The fruits are most commonly used, though all parts of the plant have similar properties The diversity of complaints against which the plant is used includes digestive problems, fainting, anaemia, sickle-cell anaemia, epilepsy, respiratory ailments, hepatic and cardiac disorders, and nutritional illnesses such as kwashiorkor, rickets, wasting and weakness. Much modern research supports the traditional uses and the plant has become an ingredient of commercially produced applications for treating skin problems[].
Of the phytochemicals elucidated in extracts of the plant, the compound groups to which activity is most frequently attributed are naphthoquinones and iridoids[].
Extracts of the bark, wood, roots and fruits possess antibacterial and antifungal properties. These extracts exhibit significant inhibitory effects in vitro against common Gram-negative and Gram-positive bacteria, and the yeast Candida albicans[].
Of the naphthoquinones isolated in fruit and root extracts, kigelinone has shown notable antimicrobial activity[].
Iridoids and dihydroisocoumarins in extracts of the bark, fruits and roots may enhance the antimicrobial activity of naphthoquinones[].
Other active antimicrobial compounds present in the bark and are the phenylpropanoids caffeic acid, p-coumaric acid and ferulic acid[].
The plant is renowned for anti-cancer properties, and laboratory screening has confirmed in-vitro anti-cancer activity[]. Fruit extracts exhibited significant effects against induced tumours. Fruit and bark extracts have shown moderate efficacy against melanotic cell lines. The naphthoquinones lapachol and isopinnatal, in some extracts of bark, wood, fruits and roots, exhibit antineoplastic activity against melanoma cell lines. Sterols and iridoids are ubiquitous in the plant and may be a factor in the activity against melanoma. The reported cytotoxicity of the root in the brine shrimp assay was attributed to the presence of γ-sitosterol.[]
The fruits have demonstrated anti-inflammatory actions in vivo[].
Cinnamic acid derivatives are thought to be responsible for anticonvulsant properties for which the plant is used to prevent epileptic fits[].
The leaves and fruits contain flavonoids. A high concentration of flavonoids may be responsible for antidiarrhoeal properties, increased by antimicrobial constituents[]. In contrast to the use of the plant as a laxative, preliminary studies have shown a preventive effect of leaf extracts against diarrhoea[].

The plant is used particularly to remedy a wide range of skin problems[]. Powders and infusions of the bark, leaves, stems, twigs or fruits are all 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 locally, to relieve rheumatism, sprains, haematoma and bruising; snake bite antidotes are made with an infusion of the fruits, stems, leaves, twigs or bark, taken orally or rubbed onto the bite. Infectious diseases, including leprosy, impetigo, and worm infestations in the blood, are all treated with this plant; dermal complaints and infections, such as whitlows, cysts, acne and boils, are treated with traditional medicines containing the fruits, and less frequently, the bark; sore eyes are treated with drops made from flower sap mixed with water[].

The fruits are pendulous, up to 45 cm long by 15 cm diameter, and resemble a 'German' sausage[]. They are the most commonly used part of the tree, being widely viewed as a fetish with magical properties to enhance their medicinal virtues[]. The fruits are not edible, even when fully ripe, and are said to be aphrodisiac, intoxicant, purgative and toxic[].
In particular, the fruit is used to increase breast size and function. It is given in decoction, and also massaged into the breasts, of young girls before puberty to promote an ample development, a practice said to be proven by recorded measurements[]. Infusions and decoctions are applied as a wash or rub to promote weight gain in infants. The fruit is used to increase milk flow, and as a poultice for treating conditions such as mastitis and breast cancer[]. The fruit and roots, along with the 'male' tassel of the plantain inflorescence, are boiled together to make a women's nostrum[].
The fruit is also used in the treatment of many other complaints. For example, it is used for treating scrotal elephantiasis; oedema of the legs; asthma; combined with peppers, it is used to treat constipation and piles[].
Externally, the fruit is used in poultices for treating wounds, syphilis, ulcers, boils and rheumatism[, ]. The fruit-ash when powdered is said to have disinfective and curative properties after the style of boric acid[].
Cut into pieces, the fruits are boiled with the roots of Anthocleista sp., and the liquid is taken by draught or enema for treating piles and lumbago[].

The bark and fruit are combined and used to heal sores and to restore taste[]. An oily ointment is made from the powder to rub on rheumatic parts and on malignant tumours[].

The bark is reported to contain a bitter principle and tannic acid[]. It has a somewhat bitter taste. It is pounded and taken internally for relieving asthma and for treating dysentery and VD[].
It is used, in the form of a decoction or enema, to treat dysentery and stomach and kidney complaints, but only in conjunction with other plants[]. Similar preparations are used in vapour-baths to treat snake-bite - this softens the wound, facilitating the action of medication applied afterwards[].
The heated bark is applied to women’s breasts to hasten their return to normal after a suckling child has been weaned[].
The crushed bark is applied to chronic wounds and sores - the application process is painful[].

The bark is combined with the bark of Mitragyna inermis; the roots of Xanthoxylum xanthoxyloides; and the seeds of Sterculia setigera for treating epilepsy[]. It enters into various prescriptions for the treatment of leprosy[].

The bitter-tasting root is used as a remedy for boils, sore throat, constipation and tapeworm[]. Combined with other roots, it is soaked in water which is then drunk for treating syphilis[].

The leaves are sometimes used to treat rheumatism, malaria, infertility, epilepsy, headache, dysentery, stomach and kidney complaints[]. They can be used to prepare a general tonic for improved health and growth[]. An infusion of the leaves with other leaves is used for treating an undefined venereal disease[].

Agroforestry Uses:

The extensive root system makes the plant suitable for erosion control and riverbank stabilization[, ].
The tree does not compete with nearby crops[].

Other Uses

The fruit contains tannin[].
Tannins can be extracted from the roots and stem bark[].
A black dye can be obtained from the fruit[, ].
A yellow dye can be obtained from the roots[].

In areas where stones for a fire-hearth are scarce, the fruits are used to stand pots on in a fire as they are almost fire-proof[].

The fruit husk is hollowed-out, fitted with a noose and bait and used as a mouse-trap[, ]. Dolls are also made from the husks[]. Some people make ladles and cups from the cut husk[, ].

The heartwood is pale brown to reddish-yellow; the sapwood is white-yellow[]. The wood is light, soft, but strong[, ]. It is not valued commercially, but is widely utilized by local people where it is used for items such as fence-posts (where it is believed that it does not rot); dugout canoes (so valued is it for this purpose that the tree has had to be protected in Malawi); a wide range of small items such as tool-handles, mortars, drums, boxes, and stools; the branch-wood is used for bows; and small branches are hollowed out to make enema tubes for use on children[, ].
The wood is used for fuel[].

Propagation

Seed - no pre-treatment is needed, but the germination rate is poor[]. Another report says that germination improves after the seed has been stored for 12 months[]. Soaking the seed in hot or boiling water for one minute prior to sowing will enhance germination[].
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[]. Seed usually germinates after 10 - 25 days[]. Seeds germinate better at temperatures of 23°c or higher[].
The sausage tree is not a prolific seeder. Seeds are released when the fruit rots on the ground, and plants regenerate naturally. Seed storage behaviour is orthodox; viability is maintained for more than 3 years in hermetic storage at ambient temperature with 11-15% mc; dry seeds store well in a cool place[].

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