At the recent Plant Science Student Conference in Gatersleben, Jonas Kappen proved that a scientific lecture does not necessarily have to be boring, but can be entertaining and informative. The PhD student from the Department Bioorganic Chemistry gave a talk on the exciting endeavor to elucidate the complex ring structure of the novel natural product lumnitzeralactone (see news ticker #144).
Lumnitzeralactone is a derivative of ellagic acid and it was isolated from the Indonesian mangrove species Lumnitzera racemosa Willd. The extracted fraction, in which lumnitzeralactone was present as the major component, showed potent antibacterial effects against Bacillus subtilis. So Kappen and colleagues pulled out all the stops in analytical methods, from high-resolution mass spectrometry to various NMR methods, to elucidate the structure of the suspected antibiotic. This proved to be a long way. They had to get NMR help from the Max Planck Institute for Multidisciplinary Sciences and also decided to verify the determined structure of lumnitzeralactone by a complex synthesis from ellagic acid.
But it paid off. The structure of lumnitzeralactone was elucidated beyond doubt. In a final bio-assay, the scientists wanted to check the antibiotic activity of the isolated natural compound and the synthesis product and were surprised to find out: Lumnitzeralactone has no antibiotic effect. Thus, one checked-off question gives rise to numerous others. There must have been synergistic interactions in the lumnitzeralactone extract with other compounds that could have led to the antibiotic effects, the scientists speculate.
In his lecture, Jonas Kappen presented the long journey of structural analysis like a criminal case and did not even leave out the difficult passages about putting together the structural puzzle pieces. The jury was convinced. They awarded him the prize for the best lecture. We congratulate cordially!
