Naturstoffe aus Afrikanischen Pflanzen
Zusammenfassung der Projektergebnisse
The goals of this project in the reporting period were the isolation and structure elucidation of bioactive compounds from medicinal plants of Kenya, as well as capacity building through training of young African scientists. These goals have been fully reached, as is evident from this report. There were no deviations from the original working plan. In terms of organic chemistry, the highlight in the reporting period was the discovery of dimeric anthraquinone/anthrone hybrids, presenting intriguing stereochemical problems, as they possess several elements of chirality, a stereogenic center and, simultaneously, two chiral axes. In a joint effort, involving isolation, semi-synthesis and chemical degradation, as well as the unique facilities and expertise in theoretical CD calculations established in Würzburg, the stereochemistry of joziknipholones (vide infra) could be elucidated and was published. Even more challenging is the just started stereochemical investigation of the recently discovered tetramers. In addition, chemical components of eighteen plant species were investigated and a number of further compounds, several of which were hitherto unknown, were isolated and their structures were determined. The crude extracts and pure compounds were investigated for antiplasmodial, antitumoral, antimicrobial, larvicidal and antioxidant properties. The phytochemical and bioactivity results are documented in eleven papers, of which seven have already been published or accepted for publication. With support through funds from DFG/BMZ, training for higher qualification of scientists at the MSc and PhD level was achieved. To date the total number of graduates associated to the DFG/BMZ, training program has reached ten (six MSc and four PhD). All these graduates are either teaching at a university/college or are researchers in National research institutions. The career of the Kenyan partner has developed in that he has been promoted from Lecturer to Senior Lecturer (in 2002) and then to Associate Professor (in 2006). He is currently the programme officer of the Natural Product Research Network for Eastern and Central Africa (NAPRECA). One of the outcomes of this project is the strengthening of the very fruitful collaboration among different institutions in Germany and Kenya.
