Antimicrobial activity and chemical composition of essential oil of Pelargonium odoratissimum

The chemical composition of the essential oil from the leaves of Pelargonium odoratissimum (L.) L'Her., Geraniaceae, was determined and the antimicrobial activities against the Aspergillus flavus CML 1816, Aspergillus carbonarius CML1815 and Aspergillus parasiticus CMLA 817 fungi, as well the Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25 992 bacteria were evaluated. The essential oil was isolated by steam distillation using a modified Clevenger apparatus, and its constituents were identified and quantified by GC/MS and GC-FID analyses. In vitro bioanalytical testing was performed using a completely randomized design. The concentrations of essential oil employed ranged from 0.1 to 2 mu L. mL(-1) (in dimethyl sulfoxide) for the fungus species and from 1 to 500 mu L. mL(-1) for the bacteria. The diameters of the inhibition zones formed for bacteria and the mean diameters of mycelial growth in perpendicular directions for fungi were measured, followed by calculation of the percentage of inhibition. The essential oil from the leaves of P. odoratissimum furnished methyleugenol (96.80%), a phenylpropanoid. This essential oil inhibited the growth of fungi (100% inhibition) and exhibited a small effect on the bacteria at the concentrations tested.