1. Department of Pharmaceutical Chemistry, Faculty of Pharmacy Obafemi Awolowo University Ile-Ife 220005 Osun State Nigeria
2. School of Chemistry and Physics University of KwaZulu-Natal Private Bag X01 Scottsville 3209 Pietermaritzburg South Africa
3. Centre for Natural Products Discovery (CNPD), School of Pharmacy and Biomolecular Sciences Liverpool John Moores University Liverpool L3 3AF UK