1. Catalysis and Peptide Research Unit, School of Health SciencesUniversity of KwaZulu-Natal Durban 4041 South Africa
2. Department of Pure and Industrial Chemistry, Faculty of Physical SciencesUniversity of Nigeria Nsukka 410001, Enugu State Nigeria
3. School of Chemistry and PhysicsUniversity of KwaZulu-Natal Durban 4041 South Africa
4. Center for Tuberculosis Research, Division of Infectious DiseasesJohns Hopkins University School of Medicine Baltimore MD 21205 USA