A visit to Sissy's research laboratory in Kuchl is a bit like a visit to a witch's kitchen. It smells faintly of a flower meadow and when you approach the equipment, the smells remind you of various herbal teas. The extraction apparatus simmers and bubbles away and, incidentally, extracts with spectacular colors are created from the dried plant material. Depending on the plant species, these range from mint green (peppermint) to yellow (marigold) to blue (cornflower) or pink (rose petals). Sissy Häsler Gunnarsdottir, molecular biologist and researcher on the Biomedical Sciences course, is standing next to them, coincidentally also with intensely reddish hair to match the plant extracts.
In the NETTLE Interreg project, which will run for the next two years in cooperation with the University of Udine and the University of Bolzano, Sissy is researching natural extracts from 30 different transboundary alpine plant species with interesting biological activities. The project will determine the phytochemical fingerprint of the plants, e.g. with regard to antioxidant and wound-healing properties. The project aims to create a public database with all this information in order to develop cosmetic/medical formulations for the treatment of skin diseases such as acne, neurodermatitis or epidermolysis bullosa.
Together with the Wood Technology and Timber Construction course, Sissy is currently preparing concentrated extracts of various plant species such as marigold, thyme, oregano, cornflower, lady's mantle and edelweiss in the laboratory in Kuchl. The laboratory is accordingly colorful, with bags full of flowers. She is already working on 12 of the 30 species. As a first step, she shreds the dried flowers and leaves in an electric coffee grinder. This takes a few minutes to several hours, depending on the plant species. The finer the petals, the more difficult it is to shred them. In the end, the plant parts must be smaller than 500 µm in order to process them further in the so-called Soxhlet extraction apparatus.
In this apparatus, the plant material is then dissolved in a solvent mixture of ethanol and water (40:60) in several extraction cycles to form a highly concentrated extract containing all the important chemical components of the plant. The solvent is heated to boiling point in a flask, whereupon the solvent vapor rises through a side tube into the cooler and from there drips into the extraction sleeve with the plant material. In this way, the desired substances are dissolved from the solid plant material. This process takes several hours. Sissy then evaporates the ethanol in another apparatus and ends up with 160-200 ml of concentrated extract. At the end, she tests the solids content of the extract, i.e. the concentration of the substance in mg/ml. She then determines the phenol content of the extracts, as this provides an initial assessment of the antioxidant effect of the respective plant.
Sissy's extracts are then sent to the Biomedical Analysis Laboratory at SALK, where they are applied to skin cells in various concentrations. The first step is to determine how the ingredients of the plants affect the viability of the cells in order to subsequently determine the antibacterial and antioxidant properties in several experiments (see also: https://www.fh-salzburg.ac.at/fhs/aktuelles/news/projekt-nettle-ein-spannender-blick-ins-forschungslabor).