Chemical composition and in vitro leishmanicidal, antibacterial and cytotoxic activities of essential oils of the Myrtaceae family occurring in the Cerrado biome

The essential oils of Eugenia uniflora L. (EuEO), Plinia cauliflora (Mart.) (PcEO) and Syzygium cumini (L.) (ScEO), of the Myrtaceae family, were analyzed in gas chromatography with mass spectrometry in order to identify their volatile components, as well as their in vitro leishmanicidal, antibacterial and cytotoxic activities. A total of 34 compounds were identified from EuEO. The major compounds found in EuEO were germacrone (8.52%), spathulenol (8.20%), α-selinene (7.50%) and (Z)-β-elemenone (4.88%). PcEO contained 52 compounds, with the major compounds being (E)-cariophene (14.69%), β-bisabolene (9.36%), (E, E)-α-farnecene (8.07%) and globulol (7.86%). ScEO contained 38 compounds, with the major compounds being α-pinene (21.20%), globulol (15.30%), eugenol (11.20%), and α-terpineol (8.88%). Our results demonstrated that EuEO, PcEO and ScEO, tested against Leishmania amazonensis, affected promastigote growth in a dose-dependent manner. The IC50 of EuEO, PcEO and ScEO were 0.99, 0.46 and 8.78 μg/mL, respectively, while the IC50 of Amphotericin B was 0.60 μg/mL. All the EO of the species evaluated presented moderate inhibitory activity, with Minimum Inhibitory Concentration (MIC) variation of 100 to 400 μg/mL for the following bacteria tested: Streptococcus mutans, Streptococcus mitis, Streptococcus sanguinis, Streptococcus sobrinus, Streptococcus salivarius, Actinomyces naeslundii, Bacteroides fragilis, Bacteroides thetaiotaomicron, Prevotella nigrescens and Porphyromonas gingivalis. Our results showed that the IC50 values for the treated tumor cell lines ranged from 76.5 to 106.2 μg/mL for EuEO and 76.6 to 116.2 μg/mL for PcEO. ScEO was not tested on the tumor cell lines because it presented an IC50 > 400 μg/mL on normal cell lines. These results highlight the variability of the chemical composition of essential oils and the high potential of their bactericidal and leishmanicidal activities.