Chemical compound identification and antibacterial activity evaluation of cinnamon extracts obtained by subcritical n-butane and ethanol extraction

Four important Cinnamomum species in China including C. cassia, C. loureiroi, C. wilsonii, and C. burmannii were chosen to be extracted by subcritical n-butane and ethanol. The chemical compounds of extracts were identified by GC-MS and HPLC-MS, and the antibacterial activities were evaluated by agar-well diffusion assay and twofold microdilution broth method. There were 47 compounds identified in n-butane extracts and 11 compounds in ethanol extracts totally. The major compounds in n-butane extracts varied significantly among different Cinnamomum species, and (E)-cinnamaldehyde and coumarin were major compounds for C. cassia with area percentage of 74.32%; (E)-cinnamaldehyde and alpha-copaene for C. loureiroi with area percentage of 67.83%; linalool, (E)-cinnamaldehyde, and citral for C. wilsonii with area percentage of 58.74%; and eugenol, (E)-cinnamaldehyde, and coumarin for C. burmannii with area percentage of 76.43%. The maximum compounds in ethanol extracts were (E)-cinnamaldehyde and (Z)-cinnamaldehyde, and others varied among the Cinnamomum species. All cinnamon extracts showed antibacterial activities that n-butane extracts were much more sensitive than ethanol extracts. The inhibition zone for N-butane extracts against Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Salmonella anatum was from 18.98 to 37.45 mm while for ethanol extracts from 7.11 to 10.11 mm. The minimum bactericidal concentrations for n-butane extracts were ranged from 0.31 to 2.50 mg/ml and for ethanol extracts ranged from 20.00 to 160.00 mg/ml. N-butane extracts of C. cassia and C. loureiroi processed much higher antibacterial activities than C. wilsonii and C. burmannii. N-butane extracts of C. cassia and C. loureiroi have the potential to be used as food biopreservative.