1. Laboratory of Animal Physiology, Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde I, P.O. Box 812 Yaounde, Cameroon
2. Laboratory of Animal Physiology and Phytopharmacology, Department of Animal Biology, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon
3. Faculty of Health Sciences, Protestant University of Central Africa, P.O. Box 4011 Yaounde, Cameroon
4. Department of Pharmacognosy, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria