The concentration and the chemical composition of the essential oils obtained from different samples of Cymbopogon citratus were evaluated. Among the 12 samples investigated (11 dried leaf samples and fresh plant leaves), seven presented essential oil concentrations within the threshold established by the Brazilian legislation. The moisture content was also determined and the majority of the samples presented humidity contents near 12%. The GC and GC/MS analyses of the essential oils led to identification of 22 compounds, with neral and geranial as the two major components. The total percentage of these two compounds varied within the investigated sample oils from 40.7% to 75.4%. In addition, a considerable variation in the chemical composition of the analyzed samples was observed. The process of grinding the leaves significantly decreased (by up to 68%) the essential oil content, as well as the percentage of myrcene in the oils.

The aim of this work was to evaluate the antibacterial and antibiofilm activity of microencapsulated and non-microencapsulated clove (Syzygium aromaticum) essential oil on multidrug-resistant Staphylococcus aureus strains. Antibacterial activity was performed by disk diffusion and broth microdilution techniques to determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the essential oil. For the antibiofilm activity, strains of S. aureus that were sensitive to the action of the essential oil were used. Five isolates were sensitive to the action of the essential oil by the disk diffusion test whose MIC was 10 μL.mL^-1 and the CBM was 20 μL.mL^-1. Of these five, four were able to form biofilms with adhesion greater than 107 CFU.cm^-2. The microencapsulated oil showed a better antibiofilm effect with a reduction of about 2 log CFU.cm^-2 in the multiresistant S. aureus analyzed, and the non-microencapsulated oil reduced approximately 1.1 log CFU.cm^-2 showing the high efficiency of the oil with microencapsulation. The use of microencapsulated Syzygium aromaticum essential oil could serve as a promising alternative in the control of multiresistant and biofilm forming bacteria on stainless steel surfaces, presenting some advantages compared to the one used in its original form, mainly with regard to transport, content preservation, handling and use in food matrices.