Chemical and Bioactive Characterization of the Essential Oils Obtained from Three Mediterranean Plants

Cupressus sempervirens L., Juniperus communis L. and Cistus ladanifer L. are Mediterranean arboreal and shrub species that possess essential oils (EO) in their leaves and branches. This study aimed at characterizing the EOs obtained by steam distillation from the three species collected in different locations from Spain (Almazán, Andévalo, Barriomartín, Cerezal, Ermitas and Huéscar). For this purpose, volatiles composition was determined by GC-MS, and different bioactivities were evaluated. The highest content in terpenes was observed in C. sempervirens (Huéscar origin) followed by J. communis (Almazán origin), corresponding to 92% and 91.9% of total compounds, respectively. With exception of C. ladanifer from Cerezal that presented viridiflorol as the most abundant compound, all the three species presented in common the α-pinene as the major compound. The EOs from C. ladanifer showed high antibacterial potential, presenting MIC values from 0.3 to 1.25 mg/mL. Concerning other bioactivities, C. ladanifer EO revealed an oxidation inhibition of 83%, while J. communis showed cytotoxicity in the MCF-7 cell line, and C. sempervirens and C. ladanifer EOs exhibited the highest potential on NCI-H460 cell lines. Nevertheless, some EOs revealed toxicity against non-tumoral cells but generally presented a GI50 value higher than that of the tumor cell lines.

Essential Oil Blends: The Potential of Combined Use for Respiratory Tract Infections

This study investigated the potential efficacy of 369 commercial essential oil combinations for antimicrobial, anti-toxic and anti-inflammatory activity with the aim of identifying synergy among essential oils commonly used in combination by aromatherapists for respiratory purposes. Essential oil combinations were assessed for their antimicrobial activities using a panel of Gram-positive, Gram-negative, and yeast strains associated with respiratory tract infections. The antimicrobial activity was measured by determining the minimal inhibitory concentration (MIC) of microbial growth. The fractional inhibitory concentration index (ΣFIC) was calculated to determine the antimicrobial interactions between the essential oils in the combination. The toxicity of the essential oil combinations was tested in vitro using the brine shrimp lethality assay, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on RAW 264.7 mouse macrophage cells and A549 lung cancer cell lines. In addition, an inflammatory response was evaluated measuring nitric oxide production. The essential oils, when in combination, demonstrated an increased antimicrobial effect, a reduction in toxicity and provided improved anti-inflammatory outcomes. Five distinct combinations [Cupressus sempervirens (cypress) in combination with Melaleuca alternifolia (tea tree), Hyssopus officinalis (hyssop) in combination with Rosmarinus officinalis (rosemary), Origanum marjorana (marjoram) in combination with M. alternifolia, Myrtus communis (myrtle) in combination with M. alternifolia and Origanum vulgare (origanum) in combination with M. alternifolia] were found to be the most promising, demonstrating antimicrobial activity, reduced cytotoxicity and improved anti-inflammatory effects. With the increased prevalence of respiratory tract infections and the growing antimicrobial resistance development associated with antimicrobial treatments, this study provides a promising complementary alternative for the appropriate use of a selection of essential oil combinations for use in the respiratory tract.

Chemical Composition, Antioxidant and Inhibitory Effect of Cupressus sempervirens Essential Oils and Methanolic Extract on Beta-lactamase producing Isolates

The Jordanian endemic medicinal plant, Cupressus sempervirens was obtained from Dhana Natural Reserve, Al-Tafilah, Jordan to investigate its antibacterial and antioxidant activities. The procuring of essential oil was made by processing of dry leaves of C. sempervirens using steam-distillation method giving 0.26% (w/w) yield. The analysis of obtained EO for its chemical constituents, was achieved by GC-MS. The equivalent of 94.02% of the entire EO has been extracted and consists of twenty-two compounds. The characterization of EO was made by their presence of three groups of chemical compounds namely Sesquiterpene hydrocarbons (71.0%), Oxygenated sesquiterpenes (11.5%) and Monoterpenes hydrocarbons (10.6%). The major constituent was germacrene-D (14.2%) along with the d-cadinene (11.0%), ß-pinene (10.0%) and isocedrol (9.8%). This conferring a chemotaxonomic value as well as a higher degree of polymorphism in the occurrence of these compounds in C. sempervirens as compared with the same species in different location worldwide. The efficiency of methanol extract and essential oil as antibacterial was evaluated against nine bacteria, using disc diffusion and MIC methods. Results showed that the methanol extract at 2000µg/disc of C. sempervirens caused the growth inhibition of Bacillus subtilis, Micrococcus luteus, Staphylococcus epidermidis and Staphylococcus aureus and producing inhibition zone ranges between 12-15mm. The MIC values recorded by essential oils of C. sempervirens were as follow: S. epidermidis and S. aureus (370µg/mL), Escherichia coli and Enterobacter aerogenes (1000µg/mL), Pseudomonas aeruginosa (2000µg/mL) and M. luteus, Klebsiella pneumonia and Salmonella typhi (3000µg/mL). In the present study, C. sempervirens extract exerted antioxidant efficiency with an IC50 value of 27.31µg/mL.

Biomonitoreo de metales pesados en vegetación arbórea en la ciudad de Saltillo

La contaminación con metales pesados es un problema grave a nivel mundial y en algunas regiones de México. En las ciudades, esto se debe principalmente a residuos o desechos de la industria y al flujo vehicular principalmente. El presente estudio está enfocado en determinar la concentración de metales pesados (Cd, Cr, Pb y V) en hojas de especies arbóreas (Pinus halepensis Mill., Cupressus sempervirens L. y Prosopis spp.). Estas especies fueron seleccionadas con la finalidad de ser utilizadas como bioindicadoras de la calidad ambiental en la ciudad de Saltillo, Coahuila, México. Se establecieron 15 puntos de muestreo, de los cuales 13 puntos fueron distribuidos aleatoriamente en la ciudad de Saltillo y dos puntos fuera de la mancha urbana. El muestreo se realizó en el mes de julio de 2019 (época del verano). El contenido de metales pesados se determinó mediante la técnica de espectrometría de emisión óptica de plasma inductivamente acoplado (ICP-OES). Se probaron las interacciones entre los factores especie-sitio con respecto a las concentraciones de metales pesados, mismas que fueron determinadas a través de los promedios obtenidos entre las muestras y sus duplicados. Destaca que el factor especie fue C. sempervirens resulto la de mayor concentración de metales pesados en Cd, Pb y V, así como P. halepensis en Cr. Los puntos 3, 4, 12 y 15 resultaron con las mayores concentraciones de los metales analizados, dichos puntos se encuentran en las zonas sureste y céntrica de la ciudad de Saltillo. El uso de especies arbóreas como bioindicadoras de metales pesados en la ciudad de Saltillo puede ser una herramienta viable para el monitoreo de la calidad ambiental.

Does Seasonality of Leaf Terpene Content and Moisture Content Trigger Leaf Flammability Seasonal Variation?

Given the importance of terpenes and fuel moisture content (FMC) on flammability, this work aims at checking how these parameters affect leaf flammability of different native and Wildland-Urban Interfaces species (Pinus halepensis, Cupressus sempervirens, Cupressocyparis leylandii, and Hesperocyparis arizonica) across seasons in the French Mediterranean region. We found that the highest terpene diversity and content seasonally varied according to the species, with diterpene content being lower in spring for C. leylandii, while monoterpene and diterpene content being higher in summer and winter, respectively, for P. halepensis. Flammability and FMC varied according to the season but the pattern differed among species. A significant correlation between the latters was rarely observed and occurred in only one season, differing among species. The correlations between flammability and terpenes were mostly highlighted using single compounds, compared to subgroups, and they presented seasonal patterns varying among species. Checking the seasonal effect of groups of terpene compounds on flammability, there were seasonal differences in these groups according to the species and the variable tested. Mostly, these significant compounds were not the most concentrated. The best flammability drivers of each model, mostly diterpenes, except for P. halepensis whose flammability was mostly drove by mono- and sesquiterpenes, changed among seasons according to the flammability variable considered. When a best driver remained the same in different seasons, its effect on flammability could be opposite. In contrast, FMC was generally not a significant explanatory parameter of leaf flammability or did not improve the fit of models.