Common Name: Sasswood Tree

General Information

Erythrophleum suaveolens is a tree; it can grow up to 25 metres tall, with occasional specimens up to 30 metres. The bole, which often branches from low down, can be 60 - 90cm in diameter[, ].
A very popular medicinal plant in Africa, it was also at one time exported to Europe[]. The wood is very durable and is commonly harvested, mainly for trade. Sasswood is also planted as an ornamental and avenue tree[].

Known Hazards

The bark contains a range of alkaloids. In high doses, the bark extract is an extremely strong, rapid-acting cardiac poison, in warm-blooded animals causing shortness of breath, seizures and cardiac arrest in a few minutes[].
Although the alkaloid content in the seeds is markedly lower than in the stem bark, the seeds are more toxic. This strong activity is due to a strong haemolytic saponin, which acts in a synergistic way to the alkaloids[].
The bark has been used in arrow poisons and as ordeal poison and the bark and leaves as fish poison[].
The sawdust may irritate mucous membranes and may cause allergy and asthma of labourers in sawmills[].

Botanical References

Range

Tropical Africa - Sierra Leone to Sudan, south to DR Congo, Zimbabwe and Mozambique.

Habitat

Moist semi-deciduous forests, gallery forest and wooded grasslands, from sea-level up to elevations of 1,100 metres[]. It is absent from the evergreen forest[].

Properties

Medicinal Rating
Other Uses Rating
Habit	Tree
Height	20.00 m
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Natural regeneration is best in fairly open forest[].
Attempts have been made to grow this species in plantations, but growth was slow[].
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[].

Edible Uses

None known

Medicinal

The bark is used as an emetic and purgative[]. A diluted decoction of the roots is used as an anthelmintic, especially against tapeworm[].
In the Western world, bark extracts were used in the late 19th century to treat heart failure. Side effects and better results with digitoxine ended this practice[].
Used externally, the crushed bark is applied to swellings caused by Filaria[]. The dried powdered bark is taken as a snuff to cure headache. A decoction of the roots and bark is applied to soothe general body pain[].

Research has shown the presence of various medically active substances in the plant, especially alkaloids. The alkaloid content of bark ranges from 0.3% to 1.5%. This varies with the age of the tree: a water extract of the bark contained 0.5% and 0.9% respectively in 60 year- and 150 year-old trees[].
The bark extract has excellent local anaesthetic activity on eyes and skin, although its use on the eye was disputed because of its irritant effect on the conjunctiva[]. Trials using it as anaesthetic in operations or tooth extractions were less successful, as symptoms of poisoning appeared in higher doses[].
The alkaloids have a stimulant effect on the heart similar to that of the cardenolides digitoxine (from Digitalis) and ouabain (from Strophanthus gratus), but the effect is very short-lasting, as the alkaloids are rapidly metabolized in the organism[]. Apart from an increase of heart contraction in systole, the alkaloids also demonstrated an increase in diastole[]. In addition, cassaine caused a violent state of excitation[].
The alkaloids also have strong diuretic effects, and increase contractions of the intestine and uterus[].
Norcassamidine has local anaesthetic action, and is a convulsant[].
The bark further contains procyanidins (polyphenols) and hence has antioxidant properties[]. The relaxant effect of the bark extract of Erythrophleum suaveolens is due to its procyanidins[].
The bark also contains the trihydroxystilbene resveratrol. Resveratrol shows antiplatelet aggregation, coronary vasodilator, antileukaemic, antifungal and protein-tyrosine kinase inhibitory activities. Trihydroxystilbenes are thought to protect against atherosclerosis and coronary heart disease[]. Resveratrol is, however, only registered as a food supplement, not as a medicine[].
The bark contains the flavone luteolin that colours orange after addition of magnesium powder and a few drops of hydrochloric acid. This reaction allows it to be distinguished from the bark of Erythrophleum africanum, which colours violet after treatment because of the presence of 2,3-dihydroxymyricetin[].

The main parts of the tree harvested for medicinal purposes are the roots and bark. Traditional herbalists use ad hoc techniques to excavate the roots and debark the stems. Virtually all trees are used, from young to old ones[].

Agroforestry Uses:

The use in agroforestry has been promoted: nitrogen fixation and the large amount of leaf litter are advantageous to intercrops[]. However, in experiments a negative effect of the leaf mulch on the yield of crops has been noted[].

Other Uses

The bark contains tannins[].

The powdered bark is mixed with the residue of palm oil processing, and after boiling it is mixed with seeds of maize, cowpea or cotton, which effectively reduces pest damage to the seeds[].
The dried leaves are mixed with stored grains and pulses to repel or kill storage insects[].

The heartwood is an orangey yellowish brown to reddish brown, darkening upon exposure; it is clearly demarcated from the 3 - 6cm wide band of creamy-yellow sapwood. The grain is interlocked; the texture coarse; the lustre is moderate. The wood is hard to very hard; heavy to very heavy; elastic; durable, even in contact with the soil, being resistant to fungi, dry wood borers and termites. It seasons slowly, with a high risk of checking and distortion; once dry it is moderately stable to stable in service. The wood is difficult to saw, with a fairly high blunting effect, stellite-tipped sawteeth and tungsten carbide tools are recommended; finishing is generally fair, but planing may be difficult due to interlocked grain; pre-boring is necessary for nails and screws; gluing properties are good for internal purposes only. The wood and iron should not be in contact in damp situations because of risks of reciprocal attack between the wood and the metal. The wood is suitable for joinery, heavy flooring, railway sleepers, harbour and dock work, turnery, construction and bridges. It is also used for boat building and wheel hubs[, ].
The wood is not highly valued as firewood but charcoal made from it is excellent[].

Propagation

Seed - takes three weeks to germinate[]. Best sown in a sunny position in a nursery seedbed[].

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