Tooth decay is a major public health problem which affects a large number of people in several countries. Even though more than 700 bacterial species have been detected in the oral cavity, Streptococcus and Lactobacillus stand out as the genera that cause tooth decay and other periodontal diseases. In this study, essential oils from Citrus aurantifolia leaves (CL-EO) and fruit peel (CP-EO) were obtained by hydrodistillation by a Clevenger-type apparatus whereas their chemical composition was analyzed by gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Limonene (77.5 %), linalool (20.1 %), citronellal (14.5 %) and citronellol (14.2 %) were the main constituents found in the essential oils from C. aurantifolia leaves and fruit peel. Antibacterial activity of essential oils was evaluated in terms of its minimum inhibitory concentration (MIC) values by the broth microdilution method in 96-well microplates. Both CL-EO and CP-EO displayed some activity against all oral pathogens under investigation; MIC values ranged from 20 to 200 µg/mL. CL-EO and CP-EO not only had promising activity against Streptococcus mutans (MIC = 20 µg/mL) and Lactobacillus casei (31.25 µg/mL), but also displayed antibacterial activity against all studied cariogenic bacteria. Efficacy of essential oils against S. mutans and L. casei is noteworthy and should be further investigated.

Leishmaniasis is an endemic disease caused by protozoa of the genus Leishmania, which affects around two million people worldwide. One major drawback in the treatment of leishmaniasis is the emergence of resistance to current chemotherapeutics. Medicinal and aromatic plants constitute a major source of natural organic compounds. In this study, the leaf essential oil of Cryptocarya aschersoniana was obtained by hydrodistillation in a Clevenger-type apparatus, and the chemical composition was analyzed by GC-MS and GC-FID. The essential oil of these species was predominantly constituted by monoterpene hydrocarbons (48.8%). Limonene (42.3%), linalool (9.7%) and nerolidol (8.6%) were the main constituents in the oil of C. aschersoniana. The in vitro activity of the oil was evaluated against the promastigote forms of Leishmania amazonensis, the causative agent of cutaneous leishmaniasis in humans. The essential oil of C. aschersoniana showed high activity against L. amazonensis promastigote forms (IC 50 = 4.46 µg/mL), however, it also demonstrated a relatively high cytotoxicity on mouse peritoneal macrophages (CC 50 = 7.71 µg/mL). This is the first report of the chemical composition and the leishmanicidal and cytotoxic activities of the leaf essential oil of C. aschersoniana.

Even though essential oils from Piper aduncum (Piperaceae) have different biological activities, little is known about their application to agricultural areas. White mold is a plant disease caused by the phytopathogen Sclerotinia sclerotiorum, which needs to be controlled by alternative measures. This study aimed at evaluating the effect of essential oils from P. aduncum leaves (PL-EO) and inflorescences (PI-EO) on the mycelial growth of S. sclerotiorum. Essential oils from P. aduncum were obtained by hydrodistillation by a Clevenger-type apparatus while their chemical composition was analyzed by GC-MS and GC-FID. Piperitone (23.4 %), myristicin (12.4 %), terpinen-4-ol (12.3 %), β-caryophyllene (7.2 %), α-humulene (6.9 %), germacrene-D (6.9 %) and dillapiol (6.3 %) were the main constituents found in oils from P. aduncum. The in vitro antifungal activity showed that PI-EO dose above 30 µL inhibited mycelial growth in 100 %, whereas PL-EO at 50 µL inhibited it in 98.74 %. This is the first report of the chemical composition of PI-EO and results suggest that the essential oils under evaluation have high potential to control the phytopathogenic fungus S. sclerotiorum.

Interest in researches into medicinal plants and therapeutic effects of essential oils (EOs) on humans has increased over the last few years. Eremanthus erythropappus, known as candeia, is a Brazilian aromatic herbaceous plant whose α-bisabolol-rich oil has been used in several cosmetic preparations. This paper reports in vitro anticaries, antimycobacterial, antileishmanial and cytotoxic activities of EOs from E. erythropappus leaves (EL-EO) and stalks (ES-EO), besides α-bisabolol, their main sesquiterpene. EL-EO and ES-EO were extracted by hydrodistillation and analyzed by GC-FID and GC-MS. α-Bisabolol, cis-α-bisabolene and β-bisabolene were identified as their major constituents. Antibacterial activity of EOs was evaluated against eight standard strains of pathogens from the American Type Culture Collection (ATCC) by determining minimum inhibitory concentrations (MICs) with the use of the microdilution method. Antibacterial activity was evaluated against Streptococcus mutans, S. mitis, S. sanguinis, S. sobrinus, S. salivarius, Mycobacterium tuberculosis, M. avium and M. kansasii. EL-EO, ES-EO and α-bisabolol exhibited high leishmanicidal activity against promastigote forms of Leishmania amazonensis; IC50 values were 9.22 µg/mL, 6.00 µg/mL and 3.12 µg/mL, respectively. The 50% cytotoxic concentrations (CC50) of EL-EO, ES-EO and α-bisabolol against mouse peritoneal macrophages were 24.65 µg/mL, 8.87 µg/mL and 1021.00 µg/mL, respectively. These results suggest that EOs from E. erythropappus seem to be very promising for the development of new bactericidal and leishmanicidal agents.