The study of Antibacterial Activity of Common Spices

Abstract

Spices are necessary food stuff used to impart good taste and aroma to food. It is also used as household medicines as well as preservatives. In this study, antibacterial activity of essential oils, acetone and methanol extracts of six different spices viz. Syzygium aromaticum Linn., Piper nigrum Linn., Curcuma longa Linn., Trachyspermum ammi Linn., Coriandrum sativum Linn. and Cinnamomum zeylanicum Blume. against ten bacteria viz. Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 200603), K. oxytoca, Salmonella Typhi, S. Paratyphi A, Pseudomonas aeruginosa (ATCC 27853), Proteus mirabilis (ATCC 49132), P. vulgaris and Shigella dysenteriae by agar well diffusion method. Among six spices, clove, ajowan and cinnamon were found to have relatively higher antibacterial activity. Essential oil of cinnamon was found to show better antibacterial activity inhibiting all tested bacteria. Essential oil of clove showed antibacterial activity against E. coli, S. aureus, K. pneumoniae, K. oxytoca, S. Typhi and P. aeruginosa. Essential oils of ajowan showed antibacterial activity against all test bacteria except P. aeruginosa. Acetone extract of clove showed antibacterial activity against E. coli, S. aureus, K. pneumoniae, S. Paratyphi A, P. aeruginosa Proteus spp. and S. dysenteriae. Acetone extract of cinnamon inhibited all test bacteria except P. aeruginosa. Methanol extract of clove showed better antibacterial activity against S. aureus, S. Paratyphi A, P. aeruginosa Proteus spp. and S. dysenteriae. MBC was determined for those extracts that possess inhibitory activity by two fold serial dilution method. The MBC value ranged from 0.39 to 25mg/ml. The lowest MBC value was given by essential oil of cinnamon against E.coli, S. aureus and S. Typhi. Gram positive bacteria were found to be more sensitive to spices than Gram negative bacteria. S. aureus was inhibited by all spices, 13 out of 18 test suspensions and E. coli was also inhibited by all spices but 8 out of 18 test suspensions. Other Gram negative bacteria were inhibited by one or two spices.