Chemical composition, antibacterial activity, and mechanism of action of essential oil from <i>Litsea cubeba</i> against foodborne bacteria
Yang Yu-jing, Mengyi Lin, Shuyi Feng, Qing Gu, Yicun Chen, Yangdong Wang, Dafeng Song, Ming Gao
Abstract
Litsea cubeba (LC) is widely used as a food flavoring. In this study, 30 components of the essential oil of Litsea cubeba (LCEO) were identified, of which α-citral (33.6534%) and β-citral (27.8042%) were identified as the main components. The diameter of the inhibition zone, minimum inhibitory concentration, and minimum bactericidal concentration of LCEO to several foodborne bacteria were evaluated. The results indicated that gram-negative bacteria (Salmonella, E. coli O157, E. coli DH5α, E. coli O104) were obviously sensitive to LCEO with Salmonella and E. coli O157 having the greatest sensitivity. According to the experimental results of the alkaline phosphatase assay, nucleic acid assay, propidium iodide staining, and electron microscopy observation, the mechanism of antibacterial effect of LCEO against Salmonella and E. coli O157 might involve the integrity of the cell membrane and wall. The results indicate that LCEO would be suitable as an effective food preservative. Practical applications In food industry, the essential oil of Litsea cubeba (LCEO) can serve as a natural preservative for fruits and vegetables, especially for foods vulnerable to gram-negative bacteria. For example, berries are likely to be attacked by Salmonella and their preservation had long been a trouble. Through spraying or soaking of LCEO, the shelf life of berries can be largely prolonged. LCEO can also be applied to animal-derived products. Due to its environmentally friendly feature, LCEO is a reassuring preservative. Otherwise, LCEO has good aroma because of large component of citral; therefore, it is also a great food flavoring.