title: Eugenol (an essential oil of clove) acts as an antibacterial agent against Salmonella typhi by disrupting the cellular membrane.
abstract: OBJECTIVE
  To evaluate the antibacterial activity of eugenol and its mechanism of bactericidal action against Salmonella typhi.
  
  
  METHODS
  The antibacterial activity was checked by disc-diffusion method, MIC, MBC, time course assay and pH sensitivity assay. The chemo-attractant property of eugenol was verified by chemotaxis assay. The mode of action of eugenol was determined by crystal violet assay, measurement of release of 260 nm absorbing material, SDS-PAGE, FT-IR spectroscopy, AFM and SEM.
  
  
  RESULTS
  Treatment with eugenol at their MIC (0.0125%) and MBC (0.025%) reduced the viability and resulted in complete inhibition of the organism. Eugenol inactivated Salmonella typhi within 60 min exposure. The chemo-attractant property of eugenol combined with the observed high antibacterial activity at alkaline pH favors the fact that the compound can work more efficiently when given in vivo. Eugenol increased the permeability of the membrane, as evidenced by crystal violet assay. The measurement of release of 260 nm absorbing intracellular materials, SDS-PAGE, SEM and AFM analysis confirmed the disruptive action of eugenol on cytoplasmic membrane. The deformation of macromolecules in the membrane, upon treatment with eugenol was verified by FT-IR spectroscopy.
  
  
  CONCLUSIONS
  The results suggest that the antibacterial activity of eugenol against Salmonella typhi is due to the interaction of eugenol on bacterial cell membrane.
authors.affiliation: Department of Biotechnology, Alagappa University, Karaikudi 630 003, Tamil Nadu, India. devikasi@yahoo.com
authors.forename: K Pandima
authors.initials: KP
authors.lastname: Devi
authors.forename: S Arif
authors.initials: SA
authors.lastname: Nisha
authors.forename: R
authors.initials: R
authors.lastname: Sakthivel
authors.forename: S Karutha
authors.initials: SK
authors.lastname: Pandian
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects; D004591:Electrophoresis, Polyacrylamide Gel; D005054:Eugenol / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D012485:Salmonella typhi / Q000187:drug effects*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000900:Anti-Bacterial Agents; D005054:Eugenol