Antimicrobial properties in bark and leaf extracts of four cinnamomum species

Abstract

BACKGROUND Cinnamon has been recognised for its flavouring and medicinal properties since ancient times and is the second most important spice sold in the world market. The antibacterial activities of hexane, chloroform, methanol and water extracts of four Cinnamomum species were studied. MATERIALS AND METHODS Both bark and leaf extracts of C. verum, C. cassia, C. tamala and C. camphora was tested in vitro against 12 bacterial species by agar well diffusion assay and minimum inhibitory concentration (MIC) was determined. The bacterial species used in the study was Listeria monocytogenes, Vibrio cholerae, Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 700603, Staphylococcus aureus ATCC 29213, Salmonella paratyphi, Salmonella typhi, Proteus mirabilis, Shigella boydii, Stenotrophomonas maltophilia ATCC 17666, Enterobacter hormaechei and Pseudomonas aeruginosa ATCC 27853. RESULTS The present study indicated that both bark and leaf extracts have the ability to inhibit Gram-positive and Gram-negative organisms. But bark extracts were more effective than leaf extracts in inhibiting the organisms. S. maltophilia was inhibited by all the tested bark extracts except methanol extracts of C. cassia and C. camphora. The diameter of zone of inhibition ranged from 16-51 mm. C. camphora hexane extracts showed least MIC value of 3.13 mg/mL with S. maltophilia. V. cholerae a potent pathogen was inhibited by C. camphora leaf chloroform extract at the MIC of 3.13 mg/mL. CONCLUSION From the present study, it could be concluded that selected extracts of cinnamon species have a remarkable potential in inhibiting the growth of major pathogenic bacteria.