1 Institute of Biochemistry and Molecular Medicine, University of Bern, CH-3012, Bern, Switzerland. Electronic address: juerg.gertsch@unibe.ch.
2 Department of Pharmaceutical Biology, Faculty of Pharmacy and Chemistry, University of Regensburg, D-93053, Regensburg, Germany. Electronic address: joerg.heilmann@chemie.uni-regensburg.de.
3 Department of Pharmacognosy & Chemistry of Natural Products, Faculty of Pharmacy, School of Health Sciences, National & Kapodistrian University of Athens, Panepistimiopolis, Zografou, 15771, Athens, Greece. Electronic address: skaltsa@pharm.uoa.gr.