1. Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
2. Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
3. Department of Pharmaceutical Sciences, School of Pharmacy, Sefako Makgatho Health Sciences University, Pretoria, South Africa
4. Department of Chemistry, Rhodes University, Grahamstown, South Africa