1. Department of Organic Chemistry, Faculty of Science, University of Yaounde I, Yaounde, Cameroon
2. Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
3. Department of Chemistry, Higher Teacher Training College, University of Yaounde I, Yaounde, Cameroon
4. Department of Biochemistry, Faculty of Science, University of Yaounde I, Yaounde, Cameroon
5. Department of pharmacy, Faculty of Medicine and Biomedical Sciences, University of Yaounde I, Yaounde, Cameroon
6. Organic and Bioorganic Chemistry, Faculty of Chemistry, Bielefeld University, Bielefeld, Germany