Essential oil of Origanum majorana L., Illicium verum Hook. f. and Cinnamomum zeylanicum Blume: chemical and antimicrobial characterization

Abstract

Essential oils of Origanum majorana L. (marjoram), Illicium verum Hook. f. (star-anise) and Cinnamomum zeylanicum Blume (cinnamon) were obtained by steam distillation using a modified Clevenger device. The antimicrobial activity of each oil was evaluated against the bacteria Staphylococcus aureus, Escherichia coli and the fungi Aspergillus flavus and Aspergillus parasiticus by observing their growth and/or mycelial inhibition through comparison with the standard dish (without oil). The essential oils were analyzed using a gas chromatograph coupled to a mass spectrometer for identification and coupled to a flame ionization detector for quantification. The major constituents of marjoram, star-anise and cinnamon essential oils were 4-terpineol, trans-anetole and cinnamic aldehyde, respectively. In in vitro tests, essential oils of marjoram and cinnamon promoted an inhibitory effect on the bacteria S. aureus and E. coli, while the essential oil of star-anise presented activity only against E. coli. Marjoram, star-anise and cinnamon oils were effective against the studied fungi, presenting an inhibitory effect. The minimal inhibitory concentration for the mycelial growth of A. parasiticus was 1 and 0.01 µL mL-1 for star-anise and cinnamon oils, respectively. The minimal inhibitory concentration for A. parasiticus was 0.25, 2 and 2 µL mL-1 for cinnamon, star-anise and marjoram oils, respectively.