Invitro antibacterial potential assessment of Carrot (Daucus carota) and Celery (Apium graveolens) seed essential oils against twenty one Bacteria

The effects of the essential oils of carrot (Daucus carota) and celery (Apium graveolens) on the proliferation of 21 pathogenic strains were examined. In the preliminary screening by DDM, 15 and 18 strains of the pathogens were susceptible to carrot and celery seed oils respectively. The MIC value of both the oils ranged from < 0.97 to >125 µl.ml against the tested strains. In contrast 9 and 7 of the strains showed higher MBC value than the MIC level against carrot and celery seed oils respectively. The activity of both the oils were found to be bactericidal in action. All the 21 test pathogens were killed within a time span of 8h by both the oils. However, the gram-positive strains showed quicker response in comparison to the gram-negative pathogens. The bactericidal activity was independent of temperature and energy occurring both at 4°C and 37°C as most of the pathogens get killed quicker at 4°C than at ambient and 37°C. The activity of both the oils persisted up to 1210C and also after sterilization and being exposed to UV rays for 8h. It indicated the heat stable nature of active compounds in both the essential oils. The activity of both the oils were increased on the exposure to U V, which implies the presence of photoactive components in both the oils. 0.8M sucrose a common osmoprotectant could not inhibit the activity of the oils indicating, activity of the oil is not through cell wall inhibition but by some other mechanism. The antibiogram pattern of the isolates and possible mode of action of the oils were assessed.