title: Evaluation of the effect of Pulicaria gnaphalodes and Perovskia abrotanoides essential oil extracts against Mycobacterium tuberculosis strains.
abstract: BACKGROUND
  Mycobacterium tuberculosis (MTB) is the causative agent of tuberculosis (TB), which remains one of the major public health problems in the world. The increasing incidence of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) worldwide highlights the urgent need to search for alternative antimycobacterial agents. More and more people in developing countries utilize traditional medicine for their major primary health care needs. It has been determined that the medicinal plants Pulicaria gnaphalodes and Perovskia abrotanoides possess strong antibacterial effect.
  
  
  METHODS
  In this study, the antimycobacterial effects of P. gnaphalodes and P. abrotanoides essential oil on MTB were examined. Essential oil was prepared from P. gnaphalodes aerial parts and P. abrotanoides flower. The effects of six different concentrations (20 μg/ml, 40 μg/ml, 80 μg/ml, 160 μg/ml, 320 μg/ml, and 640 μg/ml) were examined against sensitive isolates of MTB and MTB H37Rv (ATCC 27294).
  
  
  RESULTS
  The results showed that P. gnaphalodes and P. abrotanoides essential oil extracts have strong inhibitory effects on MTB. This activity for P. gnaphalodes was observed from very low (4%) to good (70.9%) effect; meanwhile, this activity for P. abrotanoides was observed from very low (4%) to strong (86%) effect.
  
  
  CONCLUSIONS
  The mean of inhibition percentage for P. gnaphalodes and P. abrotanoides in 640 μg/ml was 58.1% and 76.2%, respectively. So, P. abrotanoides plant is more effective against MTB than P. gnaphalodes. Identification of the effective fraction against MTB is a further step to be studied.
authors.affiliation: Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran.
authors.forename: Fereshte
authors.initials: F
authors.lastname: Hozoorbakhsh
authors.affiliation: Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Bahram Nasr
authors.initials: BN
authors.lastname: Esfahani
authors.affiliation: Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Sharareh
authors.initials: S
authors.lastname: Moghim
authors.affiliation: Isfahan Pharmaceutical Science Research Center, School of Pharmacy, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Gholamreza
authors.initials: G
authors.lastname: Asghari
keywords: Antimycobacterial effect; Perovskia abrotanoides; Pulicaria gnaphalodes; essential oil