What is it?
An extract of the bark of Anogeissus leiocarpa, a deciduous tree known as African birch that grows in savannas, bushlands and woodlands across Central, East and West Africa. Despite its name it is not a true birch; it belongs to the Combretaceae family. The bark is rich in tannins, especially ellagitannins and ellagic acid derivatives. In cosmetics it is listed as a skin-conditioning and skin-protecting ingredient.
Key information
- African birch stems are commonly used as chewing sticks for cleaning teeth in northern Nigeria.
- The stem bark contains ellagitannins such as castalagin and punicacortein, plus ellagic acid derivatives and flavonoids.
- In an acute toxicity study of a stem extract, the oral LD50 was greater than 5,000 mg/kg, indicating low acute toxicity when swallowed.
- We found no published skin irritation or allergy tests, and no CIR or EU safety review, for the bark extract.
More information
Anogeissus leiocarpa is a deciduous tree that reaches 15 to 18 meters and tolerates drought and salty soils. It is the only African species in its genus. In Sudanese traditional medicine the stem bark is made into a decoction for coughs, and preparations of the tree are used in Africa for infections and related symptoms such as diarrhea and skin rashes. In northern Nigeria its stems are chewed as tooth-cleaning sticks.
Research on the bark has focused on its polyphenols. Ellagitannins reported in the stem bark and leaves include corilagin, punicalagin, castalagin, casuarinin, chebulagic acid and punicacortein, along with ellagic acid derivatives and flavonoids, and researchers have linked these compounds to the antibacterial activity seen in laboratory tests.
Safety data are limited. A 2021 study of chewing-stick extract detected flavonoids, steroids, triterpenes, alkaloids, tannins and glycosides, and found an oral LD50 greater than 5,000 mg/kg, which indicates low acute toxicity. We found no published tests of skin irritation or allergy for the bark extract, and no safety assessment by the Cosmetic Ingredient Review (CIR) or the EU’s Scientific Committee on Consumer Safety.
On labels it appears as Anogeissus Leiocarpa Bark Extract; you may also see the spelling Anogeissus leiocarpus.
Sources: Antibiotics (2020): Potential anti-tuberculosis activity of the extracts and their active components of Anogeissus leiocarpa, with special emphasis on polyphenols; Bayero Journal of Pure and Applied Sciences (2021): Phytochemical constituents and antibacterial activities of indigenous chewing stick (Anogeissus leiocarpus) stem
