Antibacterial spectrum and cytotoxic activities of serrulatane compounds from the Australian medicinal plant Eremophila neglecta
Article first published online: 1 NOV 2011
© 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology
Journal of Applied Microbiology
Volume 112, Issue 1, pages 197–204, January 2012
How to Cite
Anakok, O.F., Ndi, C.P., Barton, M.D., Griesser, H.J. and Semple, S.J. (2012), Antibacterial spectrum and cytotoxic activities of serrulatane compounds from the Australian medicinal plant Eremophila neglecta. Journal of Applied Microbiology, 112: 197–204. doi: 10.1111/j.1365-2672.2011.05174.x
- Issue published online: 13 DEC 2011
- Article first published online: 1 NOV 2011
- Accepted manuscript online: 11 OCT 2011 12:31PM EST
- 2011/0873: received 26 May 2011, revised 21 September 2011 and accepted 5 October 2011
- antimicrobial activity;
- Australian medicinal plants;
- Eremophila neglecta;
- serrulatane diterpenoids
Aims: To determine the antibacterial spectrum and cytotoxic activities of serrulatane compounds from the Australian plant Eremophila neglecta.
Methods and Results: Antimicrobial activities of serrulatane compounds 8,19-dihydroxyserrulat-14-ene (1) and 8-hydroxyserrulat-14-en-19-oic acid (2) were tested against Gram-negative and Gram-positive bacteria including human and veterinary pathogens and some multidrug-resistant isolates. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of the compounds were determined by broth microdilution assay. Both compounds exhibited antibacterial activity against all Gram-positive test strains. They showed antimycobacterial activity against isolates of Mycobacterium fortuitum and Mycobacterium chelonae. Of the five Gram-negative bacteria tested, only Moraxella catarrhalis showed susceptibility to the compounds. Cytotoxic activities were tested in the Vero cell line. Compound 1 showed more activity than 2 in both antibacterial and cytotoxicity assays with cytotoxicity at concentrations similar to the MBC.
Conclusions: Serrulatane compounds showed significant activity against medically important bacteria, with 1 exhibiting stronger antibacterial activity. However, they also displayed toxicity to mammalian cells.
Significance and Impact of the Study: Serrulatanes are of interest as novel antibacterial compounds for use in biomedical applications; this study reports data obtained with a range of bacterial strains and mammalian cells, essential for assessing the capabilities and limitations of potential applicability of these compounds.