NTU Undergraduates' research April 2014 - Biosciences | страница 56

The antimicrobial activity of a traditionally used mixture of complex
essential oils (Olbas oil) and its additive effect when combined with
commonly used antibiotics
Amanda Bultz
School of Science and Technology, Nottingham Trent University, Clifton Lane, Clifton, Nottingham, NG11 8NS
Correspondence: [e-mail]

Plant extracts, such as essential oils, have been used in traditional medicine for many years, with the
first records dating back to c. 1500 BC. If the mechanism and actions of the extracts can be fully
understood it could be used to help combat the growing issue of antimicrobial resistance. In this
study, Olbas oil was found to possess antimicrobial activity against P. aeruginosa, E. coli and B.
subtilis. B. subtilis was the most susceptible, requiring only 0.1% v/v Olbas oil in order to kill most of
the bacterial cells present. In contrast, P. aeruginosa required a much larger concentration; at 10%
v/v, although there was some reduction in bacterial cells, this was much smaller in comparison to
the other test microorganisms. Olbas oil was combined with ten commonly used antibiotics and the
effect observed was shown to be dependent on the method used. The largest increases were shown
when the Olbas oil had been spread on to the TSA plate and the antibiotic disk placed on top. The
combination of Streptomycin and Olbas oil produced the largest increase in antimicrobial activity.
Similar increases were also observed when Olbas oil was combined with Cefpodoxime and
Ciprofloxacin. All three antibiotics have different targets within the cell, hence providing the
potential for Olbas oil to be used in conjunction with a variety of drugs. Further investigation is
required to determine the optimal concentration of both Olbas oil and the antibiotics which will
produce the greatest efficacy.