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Biosynthesis of cantharidin/palasonin in plants and insects

Objective



Research objectives and content We propose to study the biosynthesis of cantharidin, an insect sesquiterpene in parallel with palasonin a plant sesquiterpene with only one methyl substituent difference. Regarding biological activity, cantharidin has very strong Phosphatase A2 inhibitor activity and act similarly to okadaic acid and respectively, palasonin is an antihelmintic compound of Indian folk medicine. The mode of action of cantharidin in animals is also of great importance for cell biology, since the compound affects protein like Phospholipase A2. The recent work of collaborators shows that insects are able to maintain a certain level of the ' bound' toxin by reversible conjugation (probably as a imide bond). We have also good evidence that catharidin can also be found in plant systems like Neem or 'Gvtterbaum' trees. None of the individual steps of transformation from sesquiterpene farnesol are known. On another hand, we can be performed our studies on this biosynthesis in Butea frondosa plant cell culture. We have already established this plant cell culture, and we have observed the biosynthesis of (+)-palasonin in the suspension culture after stimulation with elicitor (jasmonic acid). Later, the use of plant cell culture of Neem tree, may also facilitate the search for the intermediates between farnesol and cantharidin and the 'bound' cantharidin itself. Training content (objective, benefit and expected impact) The project will include synthesis of the deuterated farnesol analogues and also palasonin and cantharidin itself realized by Diels-Alder reaction and previously described. It would be also a part of the project involving spectrometry methods for structure elucidation of the bound cantharidin. The scientific benefits of these studies would be of two levels: - Knowledge of the parallel biosyntheses in plants and in the insect of these sesquiterpenes and comparison of these in term of intermediates and final bound products. - Knowledge of the incoming source of carbon injected into the terpenood pathway in plants and insects. As part of the training, the candidate will complete his formation by learning GC/MS' for analysis of extracted intermediates derivatized (especially the deuterated products) and also high field NMR (500 MHz). The training given to the candidate would be also in natural products structure elucidation. Links with industry / industrial relevance (22)

Funding Scheme

RGI - Research grants (individual fellowships)

Coordinator

MAX-PLANCK-GESELLSCHAFT ZUR FOERDERUNG DER WISSENSCHAFTEN E.V.
Address
Carl-zeiss-promenade 10
07745 Jena
Germany