Antibacterial Activity of Palmarosa (Cymbopogon martini (Roxb.) Will.Watson) Essential Oil and Geraniol Against...

Background/Objectives: Essential oils are liquid natural volatile mixture of compounds with several bioactive properties, which make them useful in a wide range of pharmaceutical applications. The aim of this work is to explore the antimicrobial impact of Cymbopogon martini essential oil against human clinical bacterial isolates from the skin and respiratory tract while also assessing its impact on mammalian cells. Geraniol, its main component according to GC-MS analysis, was evaluated under the same conditions. Methods: The composition of the essential oil was provided by the supplier. To elucidate the antimicrobial activity, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined. The impact on mammalian hepatic cells was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results: The essential oil showed activity against Gram-positive bacteria from the Streptococcus and Staphylococcus genera, with MIC values ranging from 125 to 250 µg mL^-1 for Streptococcus agalactiae, Streptococcus anginosus, Streptococcus disgalactiae， and Streptococcus pyogenes. It also displayed activity against some of the tested Gram-negative bacteria, namely, Escherichia coli (MIC 350 µg mL^-1), Moraxella catarrhalis (MIC 250 µg mL^-1), and Morganella morganii (MIC 350 µg mL^-1). In most cases, the essential oil showed lower MIC values than geraniol. Additionally, palmarosa oil had a weaker impact than geraniol in HepG2 cells. Conclusions: Both the essential oil and the pure compound exhibited activity against clinical isolates obtained from skin and respiratory tract samples.