Abstract

Cameroon has a very rich flora, many of its plants being sources of raw materials for industrial chemicals. A very widespread one is the "Voacanga africana", the seeds of which are very rich in a substance used for the production of medicinal drugs. This project will develop a technology for the extraction of tabersonine from this plant at the small-enterprise level, instead of exporting the unprocessed seeds, as is presently the case. It will thus increase the economic value of a local produce; create employment opportunities in small-scale enterprises; provide more income for small peasant farmers and gatherers of this important crop; and open a new source of foreign currency for the country. Further, through the utilization of a local raw material, the project will contribute to a higher level of self-reliance.

Post-Project Summary

The project partially achieved its objectives by demonstrating the technical feasibility of an appropriate process to extract tabersonine from voacanga at the laboratory level. Researchers tested several extraction methods at the laboratory scale both in Yaoundé, using organic solvants, and in Edmonton, using aqueous solvants. On the basis of its simplicity, safety and cost, they selected an aqueous process for isolating tabersonine in the form of chlorhydrate. First, alkaloids from voacanga were extracted as sulphates using a diluted aqueous solution of sulphuric acid. Then, the solution was saturated with sodium chloride (NaCl) in order to transform the sulphates into chlorhydrates. Finally, a selective extraction with chloroform (CHC13) allowed the isolation of tabersonine chlorhydrate by crystalization in acetone.

The researchers also undertook a comprehensive review of the literature on tabersonine and its derivatives, as well as other voacanga alkaloids; identified European markets for tabersonine and vincamine; and examined the distribution and exploitation of voacanga trees in Cameroon. The last indicated that there there was ample voacanga seed in Cameroon to supply a small processing industry. Unfortunately, prevailing international market conditions at the time the process was developed did not warrant commercialization of tabersonine, so the project was cancelled prior to the pilot stage. Nevertheless, substantial research equipment and experience acquired through the project strengthened the research capacity of the University of Yaoundé.

Recipient Institution(s)