Prunus africana (Hook f.) Kalkman (formerly Pygeum africana Hook f.), a member of the rose family (Rosaceae), is a large tree that grows in highland/mountain forest islands and is harvested commercially in Cameroon, Kenya, Tanzania, Madagascar, and the Democratic Republic of Congo. Like the fruits of saw palmetto and the root of stinging nettle, the bark of pygeum is valued in European phytotherapy for the treatment of benign prostatic hypertrophy. (See article on page 49 of this issue.)
In African counties the bark is used by traditional healers for inflammation, kidney disease, malaria, stomachache, and fever, among other uses. Closely related to cherries, the fruits are small and very bitter. The freshly cut bark, fresh crushed leaves, and fruits contains hydrocyanic acid, thus have a strong cherry or almond fragrance. In Natal the bark was traditionally made into a tea in milk, which was used to treat problems of difficult urination. Pharmacological studies confirmed its potential value. In 1966, a patent was issued for use of the bark extract in the treatment of benign prostatic hypertrophy.
Three different classes of chemical constituents have been found in non- water-soluble extracts, including phytosterols, triterpenes, and organic acids that produce a beneficial effect on the prostate. This includes anti- inflammatory activity, reduction of cholesterol levels in the prostate, and inhibition of prostaglandin synthesis. In the past two decades, 26 clinical trials on extracts, at a dose of 100/200 mg per day, have shown positive effects in the treatment of symptoms associated with BPH such as difficulty in urination, frequent nighttime urge to urinate, and volume of residual urine. Pharmacological studies have shown it may increase prostate secretions, improving seminal fluid composition, and may improve sexual functions. Most research and clinical experience has been in Italy and France, rather than Germany. It is often used in combination with stinging nettle root and/or saw palmetto berry extracts. Its future will depend upon sustainable development of supply. A 1993 report, "Sustainability of harvesting Prunus africana bark in Cameroon," by A. B. Cunningham and F.T. Mbenkum, published in UNESCO's "People and Plants Working Papers" series, highlighted the adverse environmental impact on the harvest of bark in Cameroon and surrounding countries. This and other studies led to the inclusion of P. africana in Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) at the 9th Conference to the Parties. The listing became effective on March 15, 1995.
Better understanding of the complexities of international trade and how best to monitor the tree's survival are the subjects of a new report published by the German Federal Agency for Nature Conservation. This book explores the structure of international and national trade, resource management, and CITES implementation in countries of origin, as well as recommendations. In international trade, P. africana is sold as air-dried unprocessed bark, bark extract, and finished herbal products. Most of the harvest goes to Europe, estimated at 3,310 met ric tons per year, excluding figures from the former Zaire (Democratic Republic of Congo), due to political unrest.
According to the report, 54 percent of crude extract originates from Cameroom Madagascar is second, supplying 18 percent, followed by Tanzania at 3.6 percent. Cameroon supplies 18 percent of the crude bark in international trade, and Kenya supplies 6.3 percent of the world's bark. Most bark is locally processed, then shipped to Italy or France. This detailed report contains data on legal and illegal international trade from countries of origin. Information on harvest, manufacturing processes, and the companies that utilize or market P. africana provides identification details for crude bark from a macroscopic and organoleptic perspective. Chemical analysis of the bark is also included. The varying procedures for resource management in both Cameroon and Madagascar are explored, along with political and market factors that impact how the bark is managed and problems with obtaining accurate data on trade for current CITES reporting procedures. The authors acknowledge the need to b alance rural economic development and resource management with the need to strengthen national and regional conservation issues. Noting that European pharmaceutical/phytomedicine companies are the primary beneficiaries in the trade of P. africana products, the authors highlight the need to shift from "resource-mining" practices from wild stocks to a strategy that combines limited sustainable harvest from carefully managed wild stocks with further development of cultivated resources. This report provides a fascinating, detailed look at highly complex scientific, environmental, trade, and political issues revolving around the supply of the bark of an indigenous African tree to the world market. Given its thorough treatment of the subject with clear recommendations and strategies for long-term development of P. africana supplies, the report serves as a model for other phytomedicine source plant conservation efforts. The work includes 11 illustrations (including 22 color photographs on th ree color plates), and 10 tables that give the reader quick access to key information points. Would that we had such detailed data for all "at risk" species in international trade. Anyone who offers pygeum products should read and understand this important report.
Article copyright American Botanical Council.
By Steven Foster