Tree’s immense medicinal value now threatens its survival

Warburgia ugandensis, also known as Ugandan greenheart, is native to Uganda, Kenya, Tanzania, DR Congo, Ethiopia, Malawi and some parts of western Africa.

In Kenya, the tree is known as Muthiga (Kikuyu), Moissit (Kipsigis), Olsugunoi (Maasai) and Kumusikhu (Bukusu). It is from the plural, Kimisikhu, that Misikhu trading centre in Bungoma County got its name, as the tree was once dominant there.

It grows in ecological zones of between 800-2,400 metres above sea level and annual rainfalls of 1,000 to 1,500mm.

The leaves and seeds of this tree have a hot, peppery taste. Early Indian immigrants to Kenya used them to flavour their curries before the chilli plant was introduced.

Medicine

Warburgia is one of the most important trees in African traditional medicine. Its medicinal value is ranked second after Prunus Africana.

Its bark is boiled in water and taken orally to treat diseases like epilepsy, erectile dysfunction, skin infections and malaria.

Herbalists advise patients to chew the bark and swallow its juice for the treatment of constipation, venereal diseases, cough and fever, according to the Field Guide to the Moist Forest Trees of Tanzania by Lovett J.C. et al.

Rubbing the powdered bark to the temple of the head treats headaches and applying it to cavities treats toothaches.

The powder is also added to porridge to prevent and treat gastric ulcers. Added to milk and soups, it manages viral infections like flu. Among the Maasai, this mixture is used to treat tuberculosis.

The leaves are boiled with bathing water to treat skin conditions such as scabies, ring worms and fungal infections.

Similarly, a mixture of the leaves, bark and roots is boiled with water and taken orally to treat and prevent diarrhoea, chest pains and worm infections.

An alternative mode of administration of Warburgia ugandensis is smoke snuffing. In this method, the plant parts are burnt in a room and the patient inhales the smoke at prescribed intervals to cure a given condition.

Scientific studies show that the tree is rich in chemical compounds that have antimicrobial, antimalarial, antifungal and antibacterial properties.

In southern Ethiopia where it is known as Bafte, a study, “Isolation, characterisation and drug-likeness analysis of bioactive compounds from stem bark of Warburgia ugandensis,” established its medicinal properties.

It was carried out by Teshome Gonfa (Haramaya University), Ashehir Fisseha (Addis Ababa University) and Arumugam Thangamani (Karpagam Academy of Higher Learning, India).

Agroforestry

The heartwood contains compounds that can be used against armyworms, according to the World Agroforesty Centre.

The wood is strong and resistant to insect attack. It was commonly used for the yoke pole of ox-wagons. It is also used for building, making furniture and as a fuel.

It has a high oil content and burns well with an incense-like smell when used as fuel.

Threats

Because of its medicinal properties, a steady decline in the wild populations is emerging in African countries due to over-harvesting, according to the World Agroforesty Centre. Indeed, the species has been wiped out in many areas, including in Misikhu.

It is now listed in the International Union for Conservation of Nature red list and categorised as a species vulnerable to extinction. 

It is, therefore, advisable to establish private commercial plantations to reduce pressure on wild populations.

Propagation

Warbugia ugandensis is propagated by stem cuttings, saplings and also by seeds. Seeds take about 18 to 45 days to germinate and about three to four months to be ready for planting in the field.

Propagation through tissue culture has been successfully done at the Kenya Forestry Research Institute to support rapid multiplication of planting material.

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