African Journal of Biotechnology Vol. 5 (13), pp. 1289-1293, 3 July 2006   

ISSN 1684–5315 © 2006 Academic Journals        

Full Length Research Paper

The scientific merit of Carpobrotus mellei L. based on antimicrobial activity and chemical profiling

E. P. Springfield¹* and F. Weitz²

¹South African Traditional Medicines Research Group, School of Pharmacy, University of the Western Cape, Private Bag X17, Bellville 7535, South Africa.

²Department of Biodiversity and Conservation Biology, University of the Western Cape, Private Bag X17, Bellville 7535, South Africa.

*Corresponding authors E-mail: evan@puris.co.za; Telephone: +27 (0)21 865 2342; Puris Natural Aroma Chemicals, P.O. Box 12127, Die Boord, 7613

Accepted 31 March, 2006

Species of the genus Carpobrotus are similar in appearance and have been used for medicinal purposes over many generations. Carpobrotus mellei is endemic to the south-Western Cape of South Africa, and also used for various ailments. To date no scientific validation and information has been reported on C. mellei. This study investigated the antimicrobial potential of C. mellei against Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Mycobacterium smegmatis, and determined the minimum inhibitory concentrations (MIC) by two-fold serial dilution. C. mellei showed antimicrobial activity against S. aureus and M. smegmatis in the disc diffusion method. Eight chemical compounds showed clear zones of inhibition in the bioautograms, seven against S. aureus and three compounds were active against M. smegmatis. The ethyl acetate extracts have MIC values of 7.5 mg/ml and 15 mg/ml against S. aureus and M. smegmatis, respectively. Phytochemical tests indicated the presence of flavonoids, hydrolysable tannins, phytosterols and aromatic acids. High performance liquid chromatography (HPLC) showed a species-specific spectrum at a wavelength of 280 nm. The results confirm that C. mellei has scientific merit, and can substitute one of the other Carpobrotus species for antimicrobial usage within the south-Western Cape of South Africa.

Key words: Carpobrotus mellei, antimicrobial activity, chemical profile, scientific validation.