an investigation into the antibacterial activities of medicinal plants ...

2.2.3.1 Bulbine frutescens
Bulbine frutescens is an aloe-like plant with succulent green leaves containing a clear
gel inside the leaves that is released upon breaking or cutting the leaves (Figure 1).
Bulbine frutescens belongs to the family Aspodelaceae and is distributed in the
eastern and northern parts of South Africa. The flowering B. frutescens has clusters
of flowers on thin stalks, which may be yellow or orange in colour.
In this study the B. frutescens samples collected for investigation had clusters of
orange-coloured flowers (Figure 1). Traditionally B. frutescens are known as
‘balsemkopiva’ (Afrikaans) of which the fresh leave sap or gel are mainly used for
treating a variety of skin conditions including burns, wounds, rashes, cuts, abrasions
and boils (Table1) (Van Wyk & Gericke, 2000; Watt & Breyer-Brandwijk, 1962).
The anthraquinone knipholone isolated and identified from the fresh bulbs of B.
frutescens displayed no antibacterial activity against P. aeruginosa and S. aureus in
a disc-diffusion assay (Van Staden & Drewes, 1994). The glycoproteins, aloctin A
and aloctin B, found in the leave gel of B. frutescens are likely to be responsible for
its healing effect. These glycoproteins have also been isolated from Aloe species
that is widely used in treating skin irritations, bruises and burns (Van Wyk et al.,
1997).
2.2.3.2 Leonotis leonurus
Leonotis leonurus belongs to the family Lamiaceae with a wide natural distribution
over large parts of South Africa especially along the coast. The flowering Leonotis
leonurus has characteristic clusters of bright orange, hairy flowers on the branch
ends (Figure 1). Leonotis leonurus has long, narrow leaves with an aromatic odour,
especially upon crushing of the leaves.
Leonotis leonurus is commonly known as ‘wilde dagga’ and ‘wild dagga’ in Afrikaans
and English respectively. Traditional preparations (decoctions & infusions) of
Leonotis leonurus have a wide variety of medicinal uses externally and internally.
Traditionally fresh or dried leave decoctions are used externally to treat a variety of
21