Antimicrobial activity of Litsea cubeba, Rosmarinus officinalis and Citrus lemon essential oils against five skin-infection related pathogens

Axillary odour, athlete’s foot, eczema and infected wounds, are all conditions that are caused by organisms such as Staphylococcus aureus, Staphylococcus epidermidis, Trichophyton rubrum, Escherichia coli and Pseudomonas aeruginosa. Antimicrobial textiles such as wound dressings may go some way in combating such diseases. It is becoming increasingly important to consider the environment when selecting consumer goods such as antimicrobial textiles, problems such as toxicity and other health hazards have led to processing of textiles by more eco-friendly methods. Thus, Essential oils (EOs) may be a natural alternative to chemical based antimicrobials1.

Ten EOs were screened by the disc diffusion method against S. aureus, P. aeruginosa, E. coli, S. epidermidis and T. rubrum. The Minimum Inhibitory Concentrations (MICs), Minimum Bactericidal Concentrations (MBCs) and Fractional Inhibitory Concentrations (FICs) of Litsea cubeba (Litsea), Citrus limon (Lemon) and Rosmarinus officinalis (Rosemary) EOs were determined using the microdilution method. Litsea oil was most effective, with an average zone of inhibition (ZoI) of 47 mm, 20 mm, 53 mm, 43 mm and 90mm (complete inhibition) against S. aureus, P. aeruginosa, E. coli, S. epidermidis and T. rubrum respectively. S. aureus was the most susceptible bacterial organism, being inhibited by all EOs tested; P. aeruginosa in turn was the most resistant to the EOs. Litsea EO gave lowest MICs and MBCs against all microorganisms, with the lowest MIC and MBC observed against S. epidermidis (0.60 and 1.30 mg/ml respectively). The organisms were least susceptible to Lemon EO, with generally higher MICs and MBCs. Further investigations are underway to determine synergistic activity between the EOs and the chemical components responsible for the activity. References:

1. Kavanaugh N.L. & Ribbeck K., 2012. Selected antimicrobial essential oils eradicate Pseudomonas spp. and Staphylococcus aureus biofilms. Applied and Environmental Microbiology, 78, 4057-4061.