This study evaluated the cytotoxicity activity of the essential oils of Tagetes erecta L., Asteraceae (TE-OE), Tetradenia riparia (Hochst.) Codd, Lamiaceae (TR-OE), Bidens sulphurea (Cav.) Sch. Bip., Asteraceae (BS-OE), and Foeniculum vulgare Mill., Apiaceae (FV-OE), traditionally used in folk medicine, against the tumor cell lines murine melanoma (B16F10), human colon carcinoma (HT29), human breast adenocarcinoma (MCF-7), human cervical adenocarcinoma (HeLa), human hepatocellular liver carcinoma (HepG2), and human glioblastoma (MO59J, U343, and U251). Normal hamster lung fibroblasts (V79 cells) were included as control. The cells were treated with essential oil concentrations ranging from 3.12 to 400μg/ml for 24h. The cytotoxic activity was evaluated using the XTT assay; results were expressed as IC50, and the selectivity index was calculated. The results were compared with those achieved for classic chemotherapeutic agents. TE-OE was the most promising among the evaluated oils: it afforded the lowest IC50 values for B16F10 cells (7.47±1.08μg/ml) and HT29 cells (6.93±0.77μg/ml), as well as selectivity indices of 2.61 and 2.81, respectively. The major BS-EO, FV-EO and TE-EO chemical constituents were identified by gas chromatography mass spectrometry as being (E)-caryophyllene (10.5%), germacrene D (35.0%) and 2,6-di-tert-butyl-4-methylphenol (43.0%) (BS-EO); limonene (21.3%) and (E)-anethole (70.2%) (FV-EO); limonene (10.4%), dihydrotagetone (11.8%), α-terpinolene (18.1%) and (E)-ocimenone (13.0%) (TE-EO); and fenchone (6.1%), dronabinol (11.0%), aromadendrene oxide (14.7%) and (E,E)–farnesol (15.0%) (TR-EO). 2,6-di-tert-butyl-4-methylphenol (43.0%), (E)-anethole (70.2%) and α-terpinolene (18.1%), respectively. These results suggest that TE-OE may be used to treat cancer without affecting normal cells

Dental prosthesis supports Candida species growth and may predispose the oral cavity to lesions. C. tropicalis has emerged as a colonizer of prosthesis and has shown resistance to clinically used antifungal agents, which has increased the search for new antifungals. This work describes the effectiveness of fifteen essential oils (EOs) against C. tropicalis. The EOs were obtained by hydrodistillation and were chemically characterized by gas chromatography-mass spectrometry. The antifungal activities of the EOs were evaluated by the microdilution method and showed that Pelargonium graveolens (Geraniaceae) (PG-EO) was the most effective oil. Geraniol and linalool were the major constituents of PG-EO. The 2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide (XTT) assay showed that all the clinical C. tropicalis strains formed viable biofilms. Scanning electron microscopy examination of the biofilms revealed a complex architecture with basal layer of yeast cells and an upper layer of filamentous cells. Treatments with PG-EO, linalool, and geraniol significantly reduced the number of viable biofilm cells and inhibited biofilm formation after exposure for 48 h. PG-EO, geraniol, and linalool were not toxic to normal human lung fibroblasts (GM07492A) at the concentrations they were active against C. tropicalis. Together, our results indicated that C. tropicalis is susceptible to treatment with PG-EO, geraniol, and linalool, which could become options to prevent or treat this infection.

This work used the broth microdilution method to investigate the antimicrobial activity of the essential oil obtained from the leaves ofPlectranthus neochilus(PN-EO) against a representative panel of oral pathogens. We assessed the antimicrobial activity of this oil in terms of the minimum inhibitory concentration (MIC). PN-EO displayed moderate activity againstEnterococcus faecalis(MIC = 250 μg/mL) andStreptococcus salivarus(MIC = 250 μg/mL), significant activity againstStreptococcus sobrinus(MIC = 62.5 μg/mL),Streptococcus sanguinis(MIC = 62.5 μg/mL),Streptococcus mitis(MIC = 31.25 μg/mL), andLactobacillus casei(MIC = 31.25 μg/mL), and interesting activity againstStreptococcus mutans(MIC = 3.9 μg/mL). GC-FID and GC-MS helped to identify thirty-one compounds in PN-EO;α-pinene (1, 14.1%),β-pinene (2, 7.1%),trans-caryophyllene (3, 29.8%), and caryophyllene oxide (4, 12.8%) were the major chemical constituents of this essential oil. When tested alone, compounds1,2,3, and4were inactive (MIC > 4000 μg/mL) against all the microorganisms. These results suggested that the essential oil extracted from the leaves ofPlectranthus neochilusdisplays promising activity against most of the evaluated cariogenic bacteria, especiallyS. mutans.

This study reports on the chemical composition and antimicrobial activity of the essential oil from Artemisia absinthium L. leaves AA EO collected in Brazil against a representative panel of cariogenic bacteria. The minimum inhibitory concentrations MICs were determined by the broth dilution method in 96-well microplates. AA EO was inactive against most of the investigated oral pathogens, but it displayed moderate activity against Streptococcus mutans MIC = 250 μg/mL and very promising activity against Streptococcus mitis MIC = 62.5 μg/mL. Gas chromatography GC FID and gas chromatography mass spectrometry GC-MS revealed that camphor 1, 19.0 %, E-caryophyllene 2, 9.3 %, eucalyptol 3, 6.8 %, germacrene D 6.7 %, and α-cadinol 6.5 % were the major chemical constituents of AA EO. However, when tested alone, compounds 1, 2, and 3 were inactive MIC > 1000 μg/mL against all the studied microorganisms.