CD Laboratory for Receptor Biotechnology II

Plant extracts and their interaction with certain hormone receptors are investigated here. On the one hand, we are interested in the binding of components of the extracts to steroid receptors and, on the other hand, in the effects of these bindings on the structure and position of the receptors.

Natural plant extracts can improve health very effectively as dietary supplements. In fact, they can also be marketed as medicinal products (herbal remedies) if their modes of action and compositions as well as the natural variations in these compositions are known. It is precisely these aspects that are being researched for extracts that show healing effects in hormone-related diseases. Particular attention is paid to the fact that the effect of these extracts is caused by the binding of certain components to steroid receptors. The receptors from the steroid thyroid superfamily are of particular interest.

It should be noted that plant extracts - in contrast to synthetically produced medicines - can contain up to several hundred different substances. Therefore, a simple monocausal analysis cannot be used to investigate the mode of action of such extracts; instead, new approaches must be taken.

One of these methods is the so-called ligand binding test, for which yeast cells are genetically modified so that they present steroid receptors on their cell surface. The binding of active substances (ligands) to these receptors can be measured by the displacement of other, labelled ligands. Another variant is the transactivation test, in which the genomic pathway of the mode of action of steroid receptors in yeast is replicated and "coupled" to the synthesis of a reporter protein. Activation of the receptor can be easily recognised on the basis of the reporter protein. In addition, heterodimerisation - i.e. the composition of a receptor protein from different subunits - is taken into account.

With the aid of various methods (HPLC, HPLC-MS, CEC-MS, in vitro tests), the various components of the plant extracts are identified and isolated. The same is done with the metabolic products produced by the degradation of the plant extracts in the body. This will also form the basis for the identification of so-called biomarkers, which provide information about the degradation of the plant extracts in the body. In addition, the hormone-induced transport of a receptor through pores in the cell nucleus envelope will be simulated.

Overall, the work allows us to improve our understanding of certain plant extracts and their modes of action in the body.