Table of Contents Author Guidelines Submit a Manuscript
International Journal of Microbiology
Volume 2016 (2016), Article ID 7352509, 9 pages
Research Article

Chemical Composition and Antibacterial Activity of Essential Oils of Tagetes minuta (Asteraceae) against Selected Plant Pathogenic Bacteria

1School of Biological Sciences, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
2Department of Biology, Faculty of Science, Mwenge Catholic University, P.O. Box 1226, Moshi, Tanzania
3Department of Biological Sciences, School of Science and Information Sciences, Maasai Mara University, P.O. Box 861-20500, Narok, Kenya

Received 9 July 2016; Accepted 18 August 2016

Academic Editor: Joseph Falkinham

Copyright © 2016 Martin Muthee Gakuubi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The objective of this study was to determine the chemical composition and antibacterial activity of essential oils (EOs) of Tagetes minuta against three phytopathogenic bacteria Pseudomonas savastanoi pv. phaseolicola, Xanthomonas axonopodis pv. phaseoli, and Xanthomonas axonopodis pv. manihotis. The essential oils were extracted using steam distillation method in a modified Clevenger-type apparatus while antibacterial activity of the EOs was evaluated by disc diffusion method. Gas chromatography coupled to mass spectrometry (GC/MS) was used for analysis of the chemical profile of the EOs. Twenty compounds corresponding to 96% of the total essential oils were identified with 70% and 30% of the identified components being monoterpenes and sesquiterpenes, respectively. The essential oils of T. minuta revealed promising antibacterial activities against the test pathogens with Pseudomonas savastanoi pv. phaseolicola being the most susceptible with mean inhibition zone diameters of 41.83 and 44.83 mm after 24 and 48 hours, respectively. The minimum inhibitory concentrations and minimum bactericidal concentrations of the EOs on the test bacteria were in the ranges of 24–48 mg/mL and 95–190 mg/mL, respectively. These findings provide a scientific basis for the use of T. minuta essential oils as a botanical pesticide for management of phytopathogenic bacteria.