African Journal of Biotechnology Vol. 5 (12), pp. 1254-1258, 16 June 2006   

ISSN 1684–5315 © 2006 Academic Journals        

Full Length Research Paper

Antimicrobial activity of extracts and a germacranolide-type sesquiterpene lactone from Tithonia diversifolia leaf extract

C. A. Obafemi¹*, T. O. Sulaimon¹, D. A. Akinpelu², T. A. Olugbade³

¹Department of Chemistry, Faculty of Science, Obafemi Awolowo University, Ile-Ife, Nigeria.

²Department of Microbiology, Faculty of Science, Obafemi Awolowo University, Ile-Ife, Nigeria.

³Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria.

*Corresponding authors E-mail: efeobano2002@yahoo.com.

Accepted 8 June, 2006

The in vitro antimicrobial activity of the hexane, ethyl acetate and methanol extracts of the leaf of Tithonia diversifolia, and one sesquiterpene lactone 1 isolated from the ethyl acetate extract was studied. Of the fourteen strains of bacteria used, the ethyl acetate extract was the most active, showing inhibitory activity against five Gram +ve and two Gram –ve organisms. This was followed by the hexane extract and then methanol. The ethyl acetate fractions (TDE 2 – TDE 5, TDE 7, TDE 8 and TDE 10) showed varying degrees of inhibitory activity. The sesquiterpene lactone 1 showed activity against all the tested microorganisms, except Staphylococcus aureus and Bacillus cereus (MICs = 15.6 – 62.5 mg/ml for most stains). All the extracts, fractions and compound 1 showed activity against the fungus Candida albicans. The results of the present study indicate that the non-polar leaf extract of T. diversifolia could be useful in the treatment of some disease conditions and the sesquiterpene lactone 1 could be a good candidate as a phytotherapeutic agent against some bacterial infections.

Key words: Tithonia diversifolia, antimicrobial activity, sequiterpene lactone.