1. Department of Biology and Environmental Sciences, Sefako Makgatho Health Sciences University, Medunsa, P.O. Box 235, Ga-Rankuwa 0204, North West, South Africa
2. Department of Botany, University of Zululand, Private Bag X1001, KwaDlangezwa 3886, KwaZulu-Natal, South Africa
3. Department of Biochemistry and Biotechnology, Sefako Makgatho Health Sciences University, Medunsa, P.O. Box 235, Ga-Rankuwa 0204, North West, South Africa