Antimicrobial activity, cytotoxicity and chemical analysis of lemongrass essential oil (Cymbopogon flexuosus) and pure citral

Adukwu, Emmanuel C.; Adukwu, Emmanuel; Bowles, Melissa; Edwards-Jones, Valerie; Bone, Heather

Abstract

© 2016, The Author(s). The aim of this study was to determine the antimicrobial effects of lemongrass essential oil (C. flexuosus) and to determine cytotoxic effects of both test compounds on human dermal fibroblasts. Antimicrobial susceptibility screening was carried out using the disk diffusion method. Antimicrobial resistance was observed in four of five Acinetobacter baumannii strains with two strains confirmed as multi-drug-resistant (MDR). All the strains tested were susceptible to both lemongrass and citral with zones of inhibition varying between 17 to 80mm. The mean minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of citral (mic—0.14% and mbc—0.3%v/v) was lower than that of Lemongrass (mic—0.65% and mbc—1.1%v/v) determined using the microtitre plate method. Cell viability using human dermal fibroblasts (HDF; 106-05a) was determined following exposure to both compounds and a control (Grapeseed oil) using the XTT assay and the IC50 determined at 0.095% (v/v) for citral and 0.126% (v/v) for lemongrass. Grapeseed oil had no effect on cell viability. Live cell imaging was performed using the LumaScope 500 imaging equipment and changes in HDF cell morphology such as necrotic features and shrinkage were observed. The ability of lemongrass essential oil (EO) and citral to inhibit and kill MDR A. baumannii highlights its potential for use in the management of drug-resistant infections; however, in vitro cytotoxicity does suggest further tests are needed before in vivo or ex vivo human exposure.

Citation

Adukwu, E. C., Adukwu, E., Bowles, M., Edwards-Jones, V., & Bone, H. (2016). Antimicrobial activity, cytotoxicity and chemical analysis of lemongrass essential oil (Cymbopogon flexuosus) and pure citral. Applied Microbiology and Biotechnology, 100(22), 9619-9627. https://doi.org/10.1007/s00253-016-7807-y

• Journal Article Type: Article
• Acceptance Date: Aug 9, 2016
• Online Publication Date: Aug 26, 2016
• Publication Date: Nov 1, 2016
• Deposit Date: May 9, 2017
• Publicly Available Date: May 9, 2017
• Journal: Applied Microbiology and Biotechnology
• Print ISSN: 0175-7598
• Electronic ISSN: 1432-0614
• Publisher: Springer (part of Springer Nature)
• Peer Reviewed: Peer Reviewed
• Volume: 100
• Issue: 22
• Pages: 9619-9627
• DOI: https://doi.org/10.1007/s00253-016-7807-y
• Keywords: Acinetobacter baumannii, lemongrass oil, multi-drug resistance, MDR, toxicity, IC50
• Public URL: https://uwe-repository.worktribe.com/output/906596
• Publisher URL: http://dx.doi.org/10.1007/s00253-016-7807-y