Abstract

Warburgia is also known as Pepperbark, Isibhaha and Peperbasboom. This tree is one of most valuable of the natural African antimicrobials and the stem and leaves have been used to treat yeast, fungal, bacterial and protozoal infections for centuries. The bark of Warburgia salutaris is used in traditional medicine as an expectorant and smoked for coughs and colds. It is also used as a topical application for sores and inflammation. Previous screening of W. salutaris showed that this plant had promising antibacterial activity. Subsequently, this endangered tree species was selected for bioassay-guided purification in order to identify the active principles. Fractionation of the toluene: ethyl acetate (7:93 v/v) extract of the stem bark by chromatographic techniques yielded a sesquiterpenoid which exhibited antimicrobial activity against Gram-positive bacteria. The compound, muzigadial, has previously been reported in two other Warburgia species, this being the first time (5Aα, 9Aα, 9Bβ)-5, 5A, 6, 7, 8, 9, 9A, 9B-Octahydro-6, 6, 9A- trimethylnaphtho[1, 2c] furan-1-(3H)-one (drimenin) and 5, 10-Dihydro-6, 7-dimethyl-4H-benzo [5, 6] cyclohepta [1, 2-b]-furan has been reported from W.salutaris.

Key words: Warburgia salutaris, plant extract, Antibacterial activity, furans, furanones.