You are currently viewing <strong>Curtisia dentata (Umlahleni)</strong>

Curtisia dentata (Umlahleni)

  • Post comments:0 Comments
  • Reading time:11 mins read

Family: Cornaceae

Scientific name: Curtisia dentata

Authority: (Burm.f.) C.A.Sm.

Common names: umlahleni (Zulu), assegai (English), assegaai (Afrikaans)

Umlahleni is one of those trees that are in high demand and are very expensive. If you go to (a website that sells a wide range of trees) umlahleni is sold for about R12 000.00 (twelve thousand rand). 

Umlahleni has strong and durable wood and during the colonial days the wood was exploited for making wagons (four-wheeled trailers pulled by animals), which were in high demand at that time. The harvesting was so excessive that nowadays it’s rare to find fully mature or over-mature trees.

Voortrekkers used the wood to make wagon parts and wooden tools amongst other things. 

Umlahleni’s wood is reddish in colour and looks very similar to mahogany wood, hence the wood was and still is used to make furniture. 

The wood was and still is also used for construction. 

These days, the umlahleni is in high demand for its medicinal benefits. The bark is the part of the tree that’s most preferred in traditional medicine. Umlahleni is such a popular medicine tree that it is on the list of the sixty most frequently traded medicinal trees in South Africa. In the Eastern Cape, umlahleni is among the top ten most commonly traded trees. 

To meet the high demand, this tree has been overexploited. Even though the bark is the most preferred part for traditional medicines, because some debarkers are unskilled, when extracting the bark, they inadvertently kill the tree because they cut into its vascular cambium. 

The high price, unsustainable harvesting, and overexploitation of this tree has landed it on the Southern African Plant Red Data List where its conservation status is recorded as “near threatened” with the population trend status as “in decline”. In some parts of the country, such as KZN, the tree is completely conservation dependent. The need to conserve the tree has resulted in the government declaring it as a “protected tree”, calling for stricter management measures to ensure its conservation.

Umlahleni is scientifically known as Curtisia dentata. The genus name, Curtisia, was given in honour of William Curtis, an English botanist, entomologist, and founder of the Curtis’s Botanical Magazine that was first published in 1787 and is still relevant in the 21st century. The genus belongs to the Cornaceae family which has about 15 genera, of which the Curtisia genus is the only one found in Africa. 

The Cornaceae family is also known as the dogwood family, this is because the most well-known genus in the entire family is Cornus, a decorative dogwood. Hence, Cornaceae is also known as dogwood.

The species name dentata is Latin for toothed, referring to the toothed or serrated margins of the species’ leaves.  

Umlahleni is geographically endemic to South Africa, Swaziland, Zimbabwe, and Mozambique. It can be found growing in forests, forest margins, grasslands, and on grassy mountain slopes. In South Africa, umlahleni can be found growing in the forest patches of the Western Cape, Eastern Cape, KZN, Mpumalanga, and Limpopo provinces. As mentioned earlier, in KZN this tree has been “in decline” due to the high demand. 

Umlahleni is a medium-sized to large, fast-growing evergreen tree that can grow up to 20 m in height. When the tree is young, the bark is smooth and grey in colour, and when it matures the bark becomes rough, dark brown to black and heavily fissured. The leaves are leathery, glossy dark green, with toothed margins, an egg shape, and pointed tips. The unscented flowers are small and cream coloured. The fruits are fleshy white and edible with a bitter taste.  

Medicinal properties:

The leaves and bark of umlahleni have extracts that are effective against bacteria, fungi, inflammation, and parasites. Hence the tree is said to have antibacterial, antimycobacterial (otherwise known as antituberculosis), antifungal, anti-inflammatory, antioxidant, and anti verotoxin (cytotoxicity) activities, and glucose utilization.


Umlahleni is a valuable medicinal plant. As mentioned earlier, the bark is the most preferred part of the plant in traditional medicine.  

  • The bark is used in the making of a concoction that is used as an aphrodisiac, which increases the sexual attraction between partners. 
  • The bark is used to make a tonic to purify the blood, as well as to make an emetic and a purgative. These are all cleansing substances.  
  • The bark is used to treat ailments such as diabetes, hypertension, malaria, and tuberculosis (due to the antituberculosis activities in the bark and leave). The plant was recently discovered as an alternative remedy for the management of obesity. 
  • The bark is used to treat skin conditions such as pimples, a rash, acne, and eczema. 
  • The extracts on the leaves contain antifungal activities that are effective against Candida albicans which causes oesopharyngeal candidiasis, an opportunistic infection often observed in patients with HIV. 
  • The bark is used to treat a number of stomach ailments such as diarrhoea, dysentery, and a bleeding stomach.
  • The bark is also used to treat sexually transmitted infections.
  • The leaves and bark are used to suppress certain types of cancers, such as esophageal cancer.

The bark is also used to set a trap for people who use witchcraft against other people or who are bewitching others, this is known as ukucupha in Zulu. 

Umlahleni has been used against parasites (flatworms) and nematodes (roundworms). The leaves of this tree contain extracts that can inhibit the mobility of nematodes. 

Umlahleni is widely used as an ornamental tree and as a long-term hedge tree in full sun or light shade. Hedge trees are a row of trees or shrubs that are planted closely next to each other. They are typically used as wind brakes or noise barriers.  


Umlahleni can be prepared in different ways to treat a number of ailments. Because of the tree’s scarcity and conservation status, many traditional healers have opted to use the bark in special mixtures and avoid using it by itself.    

  • Heartwater is a disease that is endemic to Africa. It is a tick-borne disease that can potentially kill animals such as cattle, sheep, and goats. Farmers in the Eastern Cape treat heartwater with ethnoveterinary medicine made from a mixture that comprises the bark of umlahleni and the bark of umaphipha (scientifically known as Rapanea melanophloeos).
  • To suppress aesophegeal cancer, the bark and leaves are stamped and boiled to make a decoction. The decoction is then strained, and the liquid administered orally every day until the symptoms of relief are obvious.   
  • In the Eastern Cape, diarrhoea is treated by boiling the bark in water and administering the strained liquid orally until the patient is healed.
  • Umlahleni can be used to treat dermatological ailments such as eczema and pimples. To treat pimples ground the bark into powder and make a powdered bark infusion that can be applied topically, or directly on the skin. 
  • To lose weight with umlahleni, make a decoction using the bark and take the strained liquid orally.  
  • To make an emetic to treat a bleeding stomach (or isisu segazi), soak the bark in hot water, allow the mixture to cool, strain it, and then use the liquid as an emetic.
  • The bark is also used to perform a ritualised cleansing to remove bad luck.

Historically, the bark, leaves, and twigs were used for tanning leather, a process of treating the skin and hide of animals to make leather. Leather tanning involves changing the protein structure of the animal’s skin (or hide) in order to make it durable and less likely to rot or decompose.

In a lot of ways, umlahleni is very similar to unukane (scientifically known as Ocotea bullata) in that both trees were historically over-exploited for furniture and now are over-exploited for medicinal purposes. Both umlahleni and unukane are on the list of the most traded plants in South Africa and they have a protected conservation status.

Leave a Reply