Kirti Garg and Astha Giri
Infectious diseases caused by pathogens, and food contamination caused by microorganisms, are compromising human health. The efficacies of antimicrobial agents and antibiotics, which are currently being used, have been weakened by microbial resistance, while antibiotic toxicity is a known challenge. This arises the need of natural antimicrobial agents. Spices and herbs have been long used for centuries, to enhance flavour and aroma of food, and for their antimicrobial and antioxidant activities. In this study, antimicrobial activity of aqueous and ethanolic extracts of five Indian spices i.e., Black pepper, Carom, Cinnamon, Clove and Cumin, was explored against Escherichia coli and Staphylococcus aureus, by agar dilution method and disk diffusion method. For agar dilution, aqueous and ethanolic extracts, with concentrations ranging from 0.5 mg/ml-8 mg/ml, were used. Whereas for disc diffusion method, varying concentrations of the ethanolic extracts (50%, 75% and 100%) were used. The results indicated an inhibitory effect on the growth of the microbes when using higher concentration of the extract. Clove’s bud showed the best antimicrobial effect amongst all the tested spices, having Minimum Inhibitory Concentration (MIC) less than 0.5 mg/ml for aqueous extract and 6 mg/ml for ethanolic extract against both bacteria. Amongst the tested spice extracts, Clove also had the biggest zone of inhibition i.e., 21 mm, against E. coli when using 50% ethanolic extract, while Black pepper had a zone of inhibition of 20 mm against S. aureus when using 100% ethanolic extract. It was also noted that the spice extracts, in general, were more effective against S. aureus than E. coli. Therefore, spices and particularly Clove and Black pepper extracts have great potential to be further tested and developed as novel safe antimicrobial agents
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