Antimicrobial activity of the essential oils of some spice herbs

Abstract

Essential oils were obtained from fennel seeds, dill, cumin and coriander. Their antimicrobial activity was tested on isolated clinical specimens of patients treated at the University Hospital of the School of Medicine of Botucatu, SP, UNESP. Microorganisms were grown in BHI (Brain Heart Infusion/Oxoid) at 37oC/18 hours and resuspended in 0,5 Mac Farland's Standard (1,5 x 108 CFU/mL). The diffusion method was performed, putting 10 μl of the essential oils on paper disks (6mm of diameter) (Blank Disks/CECON) at 37oC/24 hours. After this period, the disks were put on plates containing Mueller Hinton Agar (Oxoid) and inoculated with the microorganisms. After 48 hours at 37oC, inhibitory zones were measured (mm) for the respective oils and strains. The essential oil from Anethum graveolens showed antimicrobial activity against Staphylococcus aureus (inhibitory zone=18 mm), Salmonella sp. (=11 mm) and E. coli (10 mm). The Cuminum cyminum essential oil was effective against E. coli, P. aeruginosa and Salmonella sp. and their inhibitory zones were 18, 10 and 23 mm, respectively. Coriandrum sativum oil was active only against Salmonella sp. (18 mm) and Foeniculum vulgare inhibited only E. coli (9 mm).