1. Department of Plant and Soil Sciences, University of Pretoria, Pretoria, South Africa.
2. School of Pharmacy, Norwich Research Park, University of East Anglia, Norwich, United Kingdom.
3. ECOspray Ltd., Grange Farm, Hilborough, United Kingdom.
4. Faculty of Science, University of Johannesburg, Johannesburg, South Africa.
5. Department of Biochemistry, University of Pretoria, Pretoria, South Africa.