Review

Assessment techniques of antimicrobial properties of natural compounds of plant origin: current methods and future trends

Ncube N. S.¹, Afolayan A. J.² and Okoh A. I.¹*

¹Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Private Bag X1314, Alice 5700, South Africa.

²Phytomedicine Research Group, Department of Botany, University of Fort Hare, Private Bag X1314, Alice 5700, South Africa.

*Corresponding author. E-mail: aokoh@ufh.ac.za.

Accepted 8 November, 2007

Medicinal plants have recently received the attention of the pharmaceutical and scientific communities and various publications have documented the therapeutic value of natural compounds in a bid to validate claims of their biological activity. Attention has been drawn to the antimicrobial activity of plants and their metabolites due to the challenge of growing incidences of drug-resistant pathogens. Some plants have shown the ability to overcome resistance in some organisms and this has led to researchers’ investigating their mechanisms of action and isolating active compounds. Particular focus is on establishing the effect of the plant(s) extracts in terms of their microstatic and microcidal action and the spectrum of organisms affected. This has enabled exploitation of plants for the treatment of microbial infections and in the development of new antimicrobial agents. This requires rigorous research and it is therefore imperative to follow standard methods to authenticate claims of antimicrobial action. Results comparability is largely dependent on the techniques employed in the investigations and conclusive results can only be obtained if methods are standardized and universal. This paper reviews the current methods used in the investigations of the efficacy of plants as antimicrobial agents and points out some of the differences in techniques employed by different authors.

Key words: Medicinal plants, plant extracts, antimicrobial agents, antimicrobial activity.