Screening for the Antimicrobial Activities of Alcoholic and Aqueous Extracts of Some Common Spices in Egypt

The extracts of 17 spices commonly used in Egypt as food condiments were screened for their antimicrobial activities against 7 standard microbial strains (S. aureus, B. subtilis, E. coli, P. aeruginosa, S. typhi, C. albicans and A. niger). Among the tested alcoholic extracts only 3 (clove, thyme and cinnamon) showed broad spectrum antimicrobial activities. Garlic juice too showed broad spectrum antimicrobial activities. Only 4 alcoholic extracts (black pepper, safflower, coriander and myrrh) had no antimicrobial activities. The remaining extrcts (53%) showed only anti-Gram positive bacteria activities. None of all tested aqueous extracts showed antifungal activity with lower antibacterial activities compared to their alcoholic ones. The antibacterial effect of alcoholic extracts was not concentration dependant, however their antifungal effect was concentration dependant. Interestingly, both alcoholic and aqueous extracts of cinnamon and alcoholic extract of clove showed the highest antiviral activity where the TCID was reduced by about 1 log cycle. This was followed 50 by the aqueous extract of clove, garlic juice then aqueous extract of thyme, while both alcoholic and aqueous extracts of liquorice had no antiviral activity.