Pygeum

Pygeum (Prunus africana)

1. Identity: Botanical and Chemical Names, Source, and Forms

Pygeum africanum (Prunus africana or Rosaceae) is an African prune (plum) tree found in tropical Africa. Known by the common names African pygeum, African plum tree, and African cherry, it is an evergreen tree native to higher elevations of southern Africa and a member of the Rose family (Rosaceae). The evergreen tree is distributed across the entire African continent in mountain regions and is also known as Prunus africanus. The name "Pygeum" itself derives from the older botanical genus name Pygeum africanum, under which the plant was long catalogued before being reclassified; the tree was previously known as Pygeum africanum but has been re-christened Prunus africana, so information about pygeum can be found under both names.

The name of the remedy, Pygeum, comes from the name of the plant, which was discovered to botany by Gustav Mann during his first European exploration of the Cameroon range. It is a medium to large, evergreen tree with a spreading crown of 10–20 m when mature. A member of the Rose family, pygeum has been found to be useful in treating prostate problems, particularly benign prostatic hypertrophy (BPH).

The medicinal raw material is exclusively the bark. Dietary supplements that contain pygeum are made from the bark of the tree. European scientists, impressed with reports of pygeum's actions, began laboratory investigations into the active constituents in the bark, which led to the development of the modern lipophilic (fat-soluble) extract used today. A chloroform extract from the bark, referred to commercially as V-1326, is the form used to treat the symptoms associated with benign prostate hyperplasia (BPH). It is available as standardized preparations under names such as Tadenan and Pigenil, both of which are in capsule form and contain 50 mg of Prunus africana extract. Pygeum africanum is commonly used in France under the trade name Tadenan.

2. Traditional and Historical Use

The bark of the African plum tree has been used traditionally for the discomfort of benign prostatic hypertrophy (BPH) by the Zulu people of Africa. The pygeum tree is a tall evergreen native to Central and Southern Africa, and its bark has been used since ancient times to treat urinary conditions. Derived from the bark of the African cherry tree, pygeum has been used for centuries in traditional African medicine and was historically used for treating urinary issues, particularly in men, as well as for alleviating inflammation, improving sexual health, and treating fevers.

The species has a long history of traditional uses. The bark is used in numerous ways: as a wound dressing, a purgative, or an appetite stimulant, and to treat fevers, malaria, arrow poisoning, stomach pain, kidney disease, gonorrhoea, and insanity. In Kenya specifically, the plant has multiple health benefits in traditional medicine to treat chest pain, malaria, and fever; other traditional uses include diarrhoea, allergies, stomachache, diseases of the prostate gland, and kidney disease.

Its bark is traditionally used to treat chest pain, malaria, and fevers. European travellers became interested in this tree when they learned in the 1700s from South African tribes how to treat bladder discomfort and "old man's disease" with the bark. Although pygeum's use is relatively new to the United States, it has been imported from Africa to Europe since the 1700s. Europeans learned of this plant's usefulness in treating what was then known as "old man's disease." Pygeum africanum bark extract has been used to treat mild and moderate symptomatic benign prostatic hyperplasia (BPH) in France since 1969.

Traditional preparations centred on the bark. The medicinal part is the bark — specifically the dried inner bark, which has been used by traditional healers across Africa for centuries to treat urinary problems, bladder discomfort, and what was historically described as "old man's disease." When European travelers documented these practices in the 18th century, they set in motion the botanical research that would eventually produce the standardized extract in clinical use today.

3. Key Constituents and Active Compounds

The composition of P. africanum consists of phytosterols (β-sitosterol, β-sitosteryl glucoside, β-sitostenone), fatty acids, triterpenoid pentacyclic acids (ursolic, oleanolic, and their homologs), alcohols (n-docosanol and its derivatives), esters of ferulic acid, linear acetogenins, nonacosane, hentriacontane, glucopyranosyl ester of benzoic acid and β-d-glucopyranoside of diphenyl methyl alcohol, lignan isolariciresinol-9-hydroxy-7,8-dimethyl ether, and proanthocyanidins.

Most of the bioactive substances in the bark are lipid-soluble compounds, including approximately 14% triterpenes (oleanolic, crataegolic, and ursolic acids), ferulic acid esters such as N-docosanol and N-tetracosanol, and phytosterols (β-sitosterol and campesterol).

The three principal pharmacologically active categories, as characterized in the research literature, are:

• Phytosterols (principally β-sitosterol): Phytosterols, including beta-sitosterol, have anti-inflammatory effects by interfering with the formation of hormone-like substances in the body (prostaglandins) that tend to accumulate in the prostate of men with benign prostatic hyperplasia (BPH).
• Pentacyclic triterpenes (ursolic, oleanolic acids): Pentacyclic terpenes have an anti-edema, or decongesting, effect.
• Ferulic acid esters (n-docosanol, n-tetracosanol): Ferulic esters indirectly control testosterone activity in the prostate, which may reduce the risk of BPH. Ferulic acid lowers prostatic cholesterol levels and phytosterols block prostaglandin synthesis, leading to reduced pain and inflammation.

Two additional notable constituents have been isolated from the bark:

• N-butylbenzenesulfonamide (NBBS): A selective dichloromethane extract from the stem barks of Pygeum africanum revealed the highest antiandrogenic effect. Bioactivity-directed fractionation of this extract led to the isolation of N-butylbenzenesulfonamide (NBBS), indicating that extracts of the stem bark of P. africanum harbour androgen antagonistic activity.
• Atraric acid (AA): Two important constituents isolated from the bark are N-N-butylbenzenesulfonamide (NBBS) with anti-androgenic activity, and atraric acid, whose mechanism of action is to inactivate the androgen receptor by inhibiting its nuclear translocation.

4. Mechanisms of Action

The mechanism of action of Pygeum africanum remains unclear. However, several distinct mechanisms have been identified through preclinical studies:

4.1 Anti-inflammatory Effects

Pygeum can decrease the production of leukotrienes and other 5-lipoxygenase metabolites. The extract has several potentially relevant pharmacologic properties: modulation of age-related hypercontractility of the bladder detrusor muscle; anti-inflammatory activity, including inhibition of chemotactic activity of leukotrienes; inhibition of fibroblast proliferation; and improvement of prostatic histology and secretion.

4.2 Inhibition of Fibroblast and Stromal Cell Proliferation

Beginning with a preliminary demonstration of in vitro inhibition of growth factor-mediated fibroblast proliferation with Pygeum africanum extract, a detailed series of in vitro and in vivo studies on prostate growth and bladder function were undertaken, permitting the identification of putative molecular targets of Pygeum africanum extract affecting both growth factor-mediated prostate growth as well as specific parameters of bladder function. Proliferation of cultured human stromal cells, stimulated by fetal calf serum, by basic fibroblast growth factor, and by epidermal growth factor, was dose-dependently inhibited by PA extract (5–100 microg/mL). Results suggest that Pygeum africanum extract is antiproliferative and apoptotic on proliferative prostate fibroblasts and myofibroblasts but not on smooth muscle cells; mechanisms of action include TGFB1 downregulation and inhibition of FGF2-specific signaling.

4.3 Antiandrogenic Activity

The P. africanum-derived compounds atraric acid (AA) and NBBS were shown to inhibit AR-mediated transcription by blocking nuclear translocation of the androgen receptor (AR). Both compounds are described as the first known natural, complete, and specific androgen receptor antagonists isolated from this species. Pygeum inhibits the androgen and progesterone receptors, but not those of glucocorticoids and estrogens; it inhibits endogenous PSA expression and prostate cancer cell growth.

4.4 Modulation of Bladder Contractility

In animal models, Pygeum has been shown to modulate bladder contractility by reducing the sensitivity of the bladder to electrical stimulation, phenylephrine, adenosine triphosphate, and carbachol. Animal studies indicate Pygeum africanum improves contractile dysfunction by normalizing myosin isoform expression.

4.5 Effects on Adrenal Androgens and Prostatic Secretion

Fibroblast production and adrenal androgen secretion can be affected by Pygeum africanum extract. Pygeum has been shown to increase prostatic secretions and improve the composition of the seminal fluid. Specifically, Pygeum administration to men with decreased prostatic secretion has led to increased levels of total seminal fluid plus increases in alkaline phosphatase and protein content.

5. Scientific Evidence by Area of Use

5.1 Benign Prostatic Hyperplasia (BPH)

BPH is by far the most studied indication. Pygeum africanum, an extract from the bark of the African prune tree, has been utilized in Europe since 1969 for the treatment of mild to moderate symptomatic benign prostatic hyperplasia.

The 2002 Cochrane Review remains the most cited synthesis of clinical evidence. The 18 randomised controlled trials analysed involved 1,562 men and lasted from 30 to 122 days. Men using Pygeum africanum were more than twice as likely to report an improvement in overall symptoms as men getting the non-active placebo. Their peak flow of urine increased by 23% and the amount of urine remaining in the bladder after voiding decreased by 24%.

Limitations of the Cochrane Review: The trials identified mostly did not use standardized, validated assessments — such as the International Prostate Symptom Score (IPSS) or the Boyarsky score — for evaluation of urinary symptom improvement. Trials were relatively small in size and duration, making long-term effects and benefits uncertain. No trials were found that directly compared Pygeum africanum with known-to-be-effective remedies for prostate enlargement such as prescription alpha-blockers.

25-year clinical experience review: Published clinical data from 2,262 patients during the last 25 years show that P. africanum bark extract is an effective and exceptionally well-tolerated treatment for mild and moderate symptomatic BPH. The extract has several potentially relevant pharmacologic properties: modulation of age-related hypercontractility of the bladder detrusor muscle; anti-inflammatory activity, including inhibition of chemotactic activity of leukotrienes; inhibition of fibroblast proliferation; and improvement of prostatic histology and secretion.

2015 review (NCCIH): There is some limited evidence that Pygeum africanum may improve some symptoms of BPH, including urinary symptoms, flow parameters, spermogram, and quality of life. A 2015 review of clinical studies of several phytotherapeutic agents, including Pygeum africanum, found some evidence of improved urinary symptoms, flow parameters, spermogram, and quality of life. However, these studies were of short duration, performed on small groups of patients, and had varied evaluation methods.

Multicenter European trial: In a multicenter study carried out in central Europe, Pygeum africanum bark extract treatment for 2 months improved domains of the International Prostate Symptom Score (IPSS) questionnaire, quality of life (QoL), and urinary flow parameters.

Overall evidence characterization: Some studies show that pygeum might help reduce some of the symptoms of BPH by helping empty more urine from the bladder and reducing trips to the bathroom at night. But these benefits may be small, and it is not clear how pygeum compares with prescription medicines for BPH. In the case of plant extracts, the vast majority of these have not been subjected to the same rigorous pre-clinical pharmacological testing and large-scale clinical trials now required by health authorities; demonstration of their clinical efficacy in BPH has been hindered by trials of limited duration with a high placebo response.

5.2 Prostatitis and Lower Urinary Tract Symptoms (LUTS)

Pygeum africanum is mostly used for BPH and prostatic adenoma (nocturia, dysuria, pollakiuria, micturitional disorders, and/or bladder fullness). It can also be used for chronic prostatitis and obstruction-induced contractile dysfunction. Evidence specifically for prostatitis as an isolated condition, however, remains limited.

5.3 Male Fertility and Seminal Function

Pygeum has been shown to increase prostatic secretions and improve the composition of the seminal fluid. Specifically, Pygeum administration to men with decreased prostatic secretion has led to increased levels of total seminal fluid plus increases in alkaline phosphatase and protein content. Pygeum appears to be most effective in men in whom alkaline phosphatase activity is reduced (i.e., <400 IU/cm³) and there is no evidence of inflammation or infection.

In one study, the patients with no IgA in their semen demonstrated an increase in alkaline phosphatase from 265 to 485 IU/cm³, compared to those with IgA who showed only a modest increase from 213 to 281 IU/cm³. The efficiency of Pygeum africanum treatment was tested on a population where the acid phosphatase activity was shown to be reduced at two successive examinations. The treatment caused an increase in acid phosphatase activity and total protein secretion. The fact that the men who had IgA present in their ejaculate reacted more favorably to the treatment shows that Pygeum africanum is more efficient in cases where there is no prostate gland inflammation.

Evidence in this area comes primarily from small, older studies; the effect appears real but modest and population-specific. Robust, adequately powered, placebo-controlled randomized trials are lacking.

5.4 Sexual Function and Erectile Dysfunction

Pygeum extract has shown an ability, in a double-blind clinical trial, to improve the capacity of patients with benign prostatic hypertrophy (BPH) or prostatitis to achieve an erection, as determined by nocturnal penile tumescence. Presumably by alleviating the underlying condition, Pygeum can improve sexual function. This is considered an indirect effect: the improvement in erectile function is thought to be secondary to the alleviation of prostate or bladder symptoms rather than a primary androgenic or vasoactive mechanism. Evidence is limited to small trials.

5.5 Prostate Cancer (Preclinical Evidence)

An extract from the bark of Pygeum africanum has been used in Europe as a prevention and treatment of prostate disorders including benign prostatic hypertrophy (BPH). In the TRAMP mouse model, mice fed Pygeum africanum showed a significant reduction (P = 0.034) in prostate cancer incidence (35%) compared to casein-fed mice (62.5%). Pygeum africanum, which is widely used in Europe and USA for treatment of BPH, has a significant role in regulation of prostate cancer both in vitro and in vivo and therefore may be a useful supplement for people at high risk for developing prostate cancer.

The isolated compounds atraric acid and N-butylbenzene-sulfonamide were identified as androgen receptor antagonists, which play an important role in the development of prostate diseases. Antiproliferative and apoptotic effects of pygeum on prostate fibroblasts and myofibroblasts are due to downregulation of transforming growth factor B1 and inhibition of fibroblast growth factor 2-specific signaling.

Important limitation: Evidence for anti-cancer effects is entirely preclinical (cell culture and animal models). No human clinical trials have demonstrated anti-cancer efficacy for Pygeum africanum in humans.

5.6 Other Traditional Uses: Malaria, Kidney Disease, Fever

It is a unique medicinal plant known for its therapeutic values for a number of diseases, including prostate cancer, benign prostatic hyperplasia, erectile dysfunction, urinary tract disorders, skin lacerations, kidney disease, chest pain, stomach upset, inflammation, and as an aphrodisiac. However, clinical evidence for these uses is either absent or extremely limited. These remain within the domain of traditional medicine without human trial support.

6. Body Systems and Health Areas Associated with Pygeum

• Genitourinary system: Primary area of clinical and preclinical study — BPH, LUTS, nocturia, urinary flow, post-void residual volume, and chronic prostatitis.
• Male reproductive system: Prostatic secretion, seminal fluid composition, and secondary effects on fertility.
• Endocrine/hormonal system: Androgen receptor antagonism (preclinical); modulation of adrenal androgen secretion.
• Immune/inflammatory system: Inhibition of leukotriene and prostaglandin synthesis; anti-inflammatory effects on prostatic tissue.
• Musculoskeletal/bladder: Modulation of bladder detrusor contractility through myosin isoform expression normalization (animal models).

7. Dosage Forms and Reported Dosages

The usual dosage of pygeum is 50 milligrams (mg) twice per day (occasionally 100 mg twice daily) of an extract standardized to contain 14 percent triterpenes and 0.5 percent n-docosanol. A dose of 100 mg once daily appears to be as effective as the most common dosage of 50 mg twice daily.

Pygeum has been studied in clinical trials for benign prostatic hypertrophy at daily doses of 25 to 200 mg. It is available as standardized preparations Tadenan and Pigenil, both in capsule form and containing 50 mg of Prunus africana extract, with recommended dosage of twice daily.

When used for benign prostatic hypertrophy (BPH), it may take several weeks to see any beneficial effects.

8. Safety Considerations and Adverse Effects

8.1 General Tolerability

Clinical studies have concluded that Pygeum africanum is generally well-tolerated with mild adverse effects such as diarrhea, nausea, constipation, and headache. Adverse effects of Pygeum africanum were mild and comparable to placebo. The most commonly reported side effect was gastrointestinal discomfort.

The constituents of the extract have a safe toxicologic profile, and some of them have anticarcinogenic and antimutagenic properties.

8.2 Regulatory Status

The FDA has not reviewed pygeum for safety and effectiveness. It is sold as a dietary supplement in the United States, where pre-market approval is not required.

8.3 Drug Interactions

Pygeum has no known severe interactions with any drugs. Given its antiandrogenic mechanisms, caution and monitoring are warranted when used concurrently with other prostate medications, though formal interaction studies in humans are not available in the published literature.

8.4 Pregnancy, Lactation, and Pediatric Populations

There is no available information about use of pygeum during pregnancy or while breastfeeding. Pygeum is used exclusively in adult male populations in clinical research, and data on other populations are absent.

8.5 Standardization and Product Variability

Herbal products such as pygeum naturally contain many different chemicals. It is not clear which chemicals may be helpful for prostate health or how they may work to reduce symptoms of an enlarged prostate. The amounts of each chemical in a specific pygeum product may vary.

9. Conservation Status and Sourcing Considerations

In 1995, P. africana was listed in Appendix II of the Convention on International Trade in Endangered Species (CITES) — meaning it was not yet threatened by extinction, but could be if trade was not restricted. Listed as vulnerable under Appendix II of CITES, populations of the commercially valuable African highland medicinal tree Prunus africana are threatened by over-exploitation in a number of countries.

A European Union (EU) ban on imports of P. africana bark came into force in 2007 to help stocks to recover. The EU lifted the embargo four years later, based on commitments from the Cameroonian government in its National Management Plan for P. africana.

A 2015 review by the Center for International Forestry Research concluded that three decades of trade data demonstrated long-term unsustainability, as bark stripping often removes up to 100% of trunk bark, causing tree mortality rates exceeding 40% in heavily harvested areas of Cameroon and Kenya.

An important note on sourcing: Prunus africana has been listed under CITES Appendix II since 1995 due to decades of unsustainable commercial harvesting. Commercially produced bark extract continues to drive international conservation efforts, with cultivation programs initiated as alternatives to wild harvest.

References

• Wilt T, Ishani A, MacDonald R, Rutks I, Stark G. Pygeum africanum for benign prostatic hyperplasia. Cochrane Database Syst Rev. 2002;(1):CD001044. PMC Full Text.
• Ishani A, MacDonald R, Nelson D, Rutks I, Wilt TJ. Pygeum africanum for the treatment of patients with benign prostatic hyperplasia: a systematic review and quantitative meta-analysis. Am J Med. 2000;109(8):654–664. PubMed.
• Edgar AD, Levin R, Constantinou CE, Denis L. A critical review of the pharmacology of the plant extract of Pygeum africanum in the treatment of LUTS. Neurourol Urodyn. 2007;26(4):458–463. PubMed.
• Shenouda NS, Sakla MS, Newton LG, et al. Phytosterol Pygeum africanum regulates prostate cancer in vitro and in vivo. Endocrine. 2007;31(1):72–81. PubMed.
• Papaioannou M, Schleich S, Roell D, et al. Extracts from Pygeum africanum and other ethnobotanical species with antiandrogenic activity. Invest New Drugs. 2006. PubMed.
• Identification of components of Prunus africana extract that inhibit lipid peroxidation. PubMed.
• Boulbès D, Soustelle L, Costa P, et al. Pygeum africanum extract inhibits proliferation of human cultured prostatic fibroblasts and myofibroblasts. BJU Int. 2006;98(5):1106–1113. PubMed.
• Reactivation of the secretion from the prostatic gland in cases of reduced fertility. Biological study of seminal fluid modifications. PubMed.
• NIH National Center for Complementary and Integrative Health (NCCIH). Benign Prostatic Hyperplasia and Complementary and Integrative Approaches: What the Science Says.
• ScienceDirect Topics. Pygeum — an overview. Pharmacology, Toxicology and Pharmaceutical Science.
• Ishani A et al. Pygeum africanum for the treatment of patients with benign prostatic hyperplasia: A systematic review and quantitative meta-analysis. American Journal of Medicine, 2000. ScienceDirect.
• Chatelain C, Autet W, Brackman F. Pygeum africanum extract for the treatment of patients with benign prostatic hyperplasia: A review of 25 years of published experience. ScienceDirect.
• Antiproliferative Effect of Pygeum africanum Extract on Rat Prostatic Fibroblasts. Journal of Urology. AUA Journals.
• Roell D, Baniahmad A. The natural compounds atraric acid and N-butylbenzene-sulfonamide as antagonists of the human androgen receptor and inhibitors of prostate cancer cell growth. Mol Cell Endocrinol. 2011;332(1–2):1–8. ScienceDirect.
• Cochrane Complementary Medicine. Prostate enlargement — Pygeum africanum summary.
• Komakech R, et al. A Review of the Potential of Phytochemicals from Prunus africana Stem Bark for Chemoprevention and Chemotherapy of Prostate Cancer. Evidence-Based Complementary and Alternative Medicine. 2017.
• Memorial Sloan Kettering Cancer Center. Pygeum — Integrative Medicine.
• CIFOR-ICRAF Forests News. Prunus africana: A sustainable management reality check.
• Frontiers in Plant Science. A Micropropagation Protocol for the Endangered Medicinal Tree Prunus africana: Genetic Fidelity and Physiological Parameter Assessment. 2020.
• Journal of Alternative and Complementary Medicine. Prunus africana (Hook.f.) Kalkman: The Overexploitation of a Medicinal Plant Species and Its Legal Context.
• Forest Ecology and Management. The African cherry (Prunus africana): Can lessons be learned from an over-exploited medicinal tree? ScienceDirect.
• PeaceHealth Health Information Library. Pygeum.
• EBSCO Research Starters. Pygeum's Therapeutic Uses. Health and Medicine.
• ScienceDirect. Inhibition of bFGF and EGF-induced proliferation of 3T3 fibroblasts by extract of Pygeum africanum (Tadenan®).
• Wikipedia. Prunus africana.