Alzheimer´s Disease is among the most prevailing and costly neurodegenerative diseases in developed countries. Selected extracts of St. John´s wort positively influence the disease. The effect is amongst others attributed to the interaction with special ABC transporters, which export toxic peptides from the brain.
The Common St. John´s wort (Hypericum perforatum L.) is a well-known medicinal herb used for the treatment of depressions. Prominent constituents of Hypericum perforatum are naphthodianthrones, e.g. the red-colored hypericin, and polyprenylated phloroglucinols, e.g. hyperforin. These metabolites account for a number of pharmacological activities. However, their relation to anti-Alzheimer properties is unknown. Their biosynthesis is only fragmentarily understood but needs to be clarified for metabolic engineering strategies.
These metabolites are synthesized and stored in characteristic secretory structures, which make the leaf look “perforated”. Two different types of glandular structures can be distinguished: on the one hand the translucent, schizogenous oil-cavities, which are scattered throughout the entire leaf lamina and which are connected to the hyperforin-biosynthesis, and on the other hand the dark multicellular nodules, which are located at the leaf margin and contain the red naphthodianthrone hypericin.
The aim of the interdisciplinary network is to identify the metabolites connected to anti-Alzheimer properties by new metabolomics and correlation methods, to investigate their formation in the plant with respect to the physiological, biochemical and genetic background, and to use the acquired knowledge to breed better cultivars and prepare more efficient, defined extracts. The project is funded for 3 years by the Leibniz Association under the funding line National and International Networking. The project is coordinated by the Department of Bioorganic Chemistry of the Leibniz Institute of Plant Biochemistry (Wessjohann group). At the IPB the Departments Cell and Metabolic Biology (Tissier group) and Stress and Developmental Biology (Neumann group) are involved in the research. Further partners are the University of Oslo in Norway (Pahnke group), the IPK Gatersleben (Sharbel group), the Technical University Braunschweig (Beerhues group) and the University of Halle-Wittenberg (Posch group).