In vitro and in vivo Evaluation of Antimicrobial Activities of Essential Oils Extracted from Some Indigenous Spices

The study was conducted to investigate the antimicrobial activity of some indigenous essential oils (EOs) extracted by hydrodistillation from spices such as Cuminum cyminum, Amomum subulatum, Cinnamomum verum and Syzygium aromaticum against Escherichia coli, Salmonella typhi, Staphylococcus aureus, Bacillus subtilis, Aspergillus flavus and Candida albicans by performing the disc diffusion assay and minimum inhibitory concentration (MIC) in-vitro, and in vivo antibacterial effect of EOs was studied in rabbits infected with S. aureus and treatment was done at infected site immediately with EOs. Among all treated groups, C. verum EO treated group showed significant decrease in viable bacterial counts at infected site after 24h and 48h of infection to 7.4×10^6 and 7.6×10^5 cfu, respectively, from 4.3×10^7 cfu before treatment. C. verum EO was found to be the most effective against S. aureus and C. albicans, showing zone of inhibition diameters 34±2.0mm and 50.3±8.6mm, respectively. The EOs, applied at different concentrations, showed variable inhibitory effects to all the microorganisms tested and more effective than control, both in-vitro and in-vivo. The results of the present study screened out the antibacterial and antifungal potential of the EOs, however further dose dependent studies, both in-vitro and in-vivo are required to find out their maximum safe levels against bacteria and fungi.