1. Division of Pharmacognosy and Natural Products Chemistry, School of Pharmacy, University of Athens, Panepistimioupoli Zografou, Athens, Greece, Molecular Endocrinology Program, Institute of Biological Research and Biotechnology, National Hellenic Research Foundation, GR-11635 Athens, Greece, and Laboratory of Animal Physiology, Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde 1, PO Box 812, Yaounde, Cameroon