[1] Univ Johannesburg, Dept Bot & Plant Biotechnol, ZA-2006 Johannesburg, South Africa
[2] Tshwane Univ Technol, Dept Pharmaceut Sci, ZA-0001 Pretoria, South Africa
[3] Univ Witwatersrand, Fac Hlth Sci, Dept Pharm & Pharmacol, ZA-2193 Johannesburg, South Africa