Prunus africana popularly known as Pygeum is a large evergreen tree that grows in the afromontane of Africa. It is the only species of Genus Prunus native to Africa and can grow to a height of up to 40 metres. It has pendulous branches with thick, oblong-shaped, leather-like, mat-colored leaves and creamy white flowers. The fruit (drupe) resembles a cherry when ripe. The seeds are believed to be recalcitrant. The dark-brown to gray bark of the trunk is the part used for medicinal purposes. The wood is durable and has been used in household goods. The tree is present in highland mountain forests in Africa and Madagascar, occurring in Afromontane forest "islands" from 4,500 to 6,000 feet.

P. africana has been identified as top priority internationally for conservation and development because of its bark. The fresh bark, leaf, and fruits contain amygalin, yielding hydrocyanic acid when crushed; hence, they have an almond flavor. The bark extracts are used to make capsules for benign prostatic hyperplasia and propecia for male pattern baldness. The bark was traditionally powdered and drunk as a tea for genito-urinary complaints, allergies, inflammation, kidney disease, malaria, stomachache, and fever, among other uses. Folkloric use in Africa attracted the attention of European researchers, and a patent was issued in 1966 for use of a pygeum bark extract in the treatment of benign prostatic hyperplasia (BPH). Double-blind clinical trials have shown efficacy for many parameters of prostatic hypertrophy, including failure to urinate, nocturnal urination, frequent urination, residual urine, abdominal heaviness, voiding volume, prostate volume and peak flow. Results included significant reduction of symptoms and prostate size, and clearance of bladder neck urethra obstruction. The bark contains three groups of active constituents: phytosterols (including beta-sitosterol), pentacyclic triterpenoids (including ursolic and oleaic acids) and ferulic esters of long-chain fatty alcohols (including ferulic esters of docosanol and tetracosanol).

The phytosterols, particularly beta-sitosterol, are found in numerous plants and are anti-inflammatory, inhibiting the synthesis of prostaglandins. Beta-sitosterol has been shown to be useful in cases of BPH by helping to reduce the normally elevated levels of prostaglandins in these patients. The elimination of the excess blood and vasal congestion helps reduce the size of prostate adenomas. The pentacyclic triterpenoids also help inhibit inflammation by blocking enzymatic activity. They are effective anti-edema agents and also help increase the integrity of small veins and capillaries. The third active group, the ferulic esters of long-chain fatty acids, act by inhibiting the absorption and metabolism of cholesterol. BPH and other cases of enlarged prostates are characterized by containing abnormally high levels of cholesterol. Pygeum efficacy was determined by measuring the effects of the herb on numerous parameters, including dysuria, nycturia, frequent urination, abdominal heaviness, residual urine, voiding volume, prostate volume, and peak flow. Consumption of Pygeum resulted in significant amelioration of symptoms, reduction in prostate size, and clearance of bladder neck urethral obstruction. Transient side effects involving gastrointestinal irritation (inducing nausea and abdominal pain) have been reported in clinical trials.

Surrounding forests have been clear-cut for forest products and agricultural land, limiting the tree's habitat. The bark harvest, primarily taken from the wild in Cameroon, Kenya, Tanzania, Madagascar, as well as the Democratic Republic of Congo (the former Zaire), has had a devastating effect on wild populations of the species. This overexploitation sparked conservation concerns, resulting in the species being listed in Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) in 1994, becoming effective in 1995 in order to monitor species in international trade. In theory, this means that countries of export have to issue export permits and countries of import have to check these permits upon entry. The Scientific Authority of an export country advises its Management Authority on the sustainability of a consignment and, ideally, the export permit would be based on sound inventory and management information. All of the countries exporting its bark, are signatories to CITES, meaning that the bark exported to western countries is harvested from a sustainable source. However, the reality is somewhat different and, despite the legislation, the unsustainable exploitation of this species is well-recorded. Undoubtedly, quotas and permits are being issued without reference to adequate biological baseline information.

This Information was taken from the Prunus Net, provided by ICRAF.

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