The in vitro antibacterial activities of a total of 46 extracts from dietary spices and medicinal herbs were investigated by agar-well diffusion method against five foodborne bacteria (Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Salmonella anatum). Their total phenolic contents were also evaluated. Many herb and spice extracts contained high levels of phenolics and exhibited antibacterial activity against foodborne pathogens. Gram-positive bacteria were generally more sensitive to the tested extracts than Gram-negative ones. S. aureus was the most sensitive, while E. coli was the most resistant. There were highly positive relationships (R2=0.73–0.93) between antibacterial activities and phenolic content of the tested extracts against each bacterium. This suggested that the antibacterial activity of the tested extracts was closely associated with their phenolic constituents. © 2007 Elsevier B.V. All rights reserved.
ABSTRACT
Spices like turmeric, ginger, alliums are indispensable for the preparation of our daily food and are reported to possess compounds, which have varied beneficial biological effects and also prevent the microbial spoilage of food. This study evaluates the antioxidant and antimicrobial activity of spice extracts such as ginger, turmeric and garlic by 2, 2’-Diphenyl-1-picrylhydrazyl (DPPH) Radical Scavenging Method and also to evaluate their antimicrobial effects by Slant method. The antioxidant activities when compared among ginger, turmeric and garlic the potency of these spices was found to be in the order of Vit C > Ginger > Turmeric ≥ Dry garlic > Fresh garlic. The antimicrobial activity of these spices was found to be in the order of Turmeric > Ginger > Garlic. The study indicates that the spices like ginger, garlic and turmeric have antimicrobial and antioxidant activity. Further studies are needed to study the biological effects of antioxidant-rich herbs and spices on oxidative stress related diseases.