Coccolith-calcite Sr/Ca as a proxy for transient export production related to Saharan dust deposition in the tropical North Atlantic.

Atmospheric dust deposition can modulate the earth's climate and atmospheric CO2 through fertilising the ocean (nutrient source) and by accelerating the biological carbon pump through fuelling the ballasting process. To distinguish the biogeochemical effects of Saharan dust with respect to fertilization and ballasting, and to gain a broader perspective on the coccolith calcite Sr/Ca in relation to the drivers of coccolith export production, we determined the coccolith-Sr/Ca from a one-year (2012-2013) time-series sediment trap record in the western tropical North Atlantic (M4-49°N/12°W). High Sr/Ca were linked to enhanced export production in the upper part of the photic zone, most notably under windier, dry, and dustier conditions during spring. Attenuated Sr/Ca in the autumn probably reflect a combination of lower Sr-incorporation by dominant but small-size placolith-bearing species and the presence of "aged" coccoliths rapidly scavenged during a highly productive and usually fast export event, likely added by (wet) dust ballasting. Higher Sr/Ca observed in the large coccolith size fractions support the existing notion that larger-sized coccolithophores incorporate more Sr during calcification under the same environmental conditions. The presence of the abnormally Sr-rich species Scyphosphaera apsteinii is also shown in the separated large fraction of our Sr/Ca seasonal data.

Thymbra capitata essential oil has a significant antimicrobial activity against methicillin-resistant Staphylococcus aureus pre-formed biofilms.

Methicillin-resistant Staphylococcus aureus (MRSA) is a multidrug-resistant opportunistic pathogen with a great ability to form biofilms. Herein, the antimicrobial potential of Thymbra capitata essential oil (EO) against MRSA biofilms was investigated. The determination of the minimum inhibitory concentration (MIC) and the minimum lethal concentration (MLC) of the T. capitata EO was first investigated on a group of clinical isolates from septicaemias, diabetic foot ulcers and osteomyelitis. Biofilms were incubated with the EO at the MLC and its anti-biofilm potential was investigated. A strong antimicrobial activity was observed, with MIC and MLC values between 0·32 and 0·64 mg l-1 . However, the concentration of EO necessary for the eradication of planktonic cells was insufficient to significantly reduce the biofilm biomass of some isolates. Nevertheless, cell culturability and overall cellular metabolism was strongly reduced in all biofilms tested, only when the EO was tested. Contrary to the tested antibiotics, T. capitata EO showed a significant antimicrobial activity against MRSA biofilms, by reducing cellular metabolism and cellular culturability.

Antifungal activity of essential oil from Mentha spicata L. and Mentha pulegium L. growing wild in Sardinia island (Italy).

This study aims to evaluate the antifungal activity of Mentha spicata L. and Mentha pulegium L. from Sardinia and to assess their efficacy on virulence factors for Candida albicans, particularly on the inhibition of the germ tube formation. The major compounds of the essential oils were carvone (62.9%) for M. spicata and pulegone (86.2%) for M. pulegium. The essential oil from M. spicata showed a more preeminent effect against Cryptococcus neoformans and the dermatophytes Trichophyton rubrum and T. verrucosum (0.32 µL/mL). Both oils were very effective in inhibiting C. albicans germ tube formation, at doses well below their MIC (0.16 µL/mL).

Unveiling the bioactive potential of the essential oil of a Portuguese endemism, Santolina impressa.

ETHNOPHARMACOLOGICAL RELEVANCE: Santolina species are widely used in traditional medicine in the Mediterranean region for their anti-inflammatory, antimicrobial, antispasmodic, digestive, and analgesic properties. S. impressa, a Portuguese endemism, is traditionally recognized for its beneficial anti-inflammatory properties in several gastrointestinal affections and is also used in oropharyngeal infections. AIM OF THE STUDY: The present study aims to characterize the essential oil of S. impressa growing in Portugal and validate its traditional uses by assessing the anti-inflammatory potential of its essential oil at concentrations without toxicity. The antifungal properties of the oil are also addressed, as well as, the putative mechanism of action underlying these effects. MATERIAL AND METHODS: The essential oil was obtained in accordance with the European Pharmacopoeia and characterized by GC and GC-MS. The anti-inflammatory potential of the oil was assessed on LPS-stimulated macrophages, through the production of nitric oxide (NO) using the Griess reaction. Putative mechanisms of action included the role of the oil as a NO scavenger, as well as its effect on the expression of two key pro-inflammatory enzymes, iNOS and COX-2 by Western blot analysis. The antifungal effect of the oil was evaluated according to the CLSI guidelines on several yeast and filamentous strains and on two major virulence factors in Candida albicans, namely germ tubes and biofilms. Ultrastructural modifications on dermatophytes were also unveiled by transmission electron microscopy. RESULTS: S. impressa essential oil was primarily characterized by the presence of monoterpene hydrocarbons and oxygenated monoterpenes, being the main compounds ß-pinene (22.5%), 1,8-cineole (10.0%), limonene (9.1%), camphor (8.1%) and ß-phellandrene (8.0%). A significant decrease (ca 60.0%) in nitrite levels was observed in LPS-stimulated macrophages treated with the oil without affecting cell viability. This effect could be explained by a great reduction on iNOS expression (85.0% inhibition), thus underpinning the anti-inflammatory potential of the oil. The oil also showed a fungicidal effect, being more active against Cryptococcus neoformans, Epidermophyton floccosum and Trichophytum rubrum. For these dermatophytes, significant ultrastructural modifications in cell wall structure were detected. Strikingly, for C. albicans, the oil showed a significant anti-infective potential (at 0.07 mg/mL for germ tube inhibition and 0.02 mg/mL for biofilm disruption) before fungal growth inhibition occurred. CONCLUSIONS: Our results validate the main traditional use ascribed to S. impressa, namely its anti-inflammatory effect. In addition, an antifungal potential is pointed out, thus corroborating the antimicrobial uses and adding new value to an endemic species poorly recognized by the industry.

Assessment of safe bioactive doses of Foeniculum vulgare Mill. essential oil from Portugal.

This study was designed to evaluate the antifungal activity of Foeniculum vulgare essential oil; concomitantly, the safety of bioactive doses was also unveiled, for the first time, in several mammalian cells. The chemical characterisation was made by GC and GC-MS. Antifungal activity was evaluated against yeasts, dermatophytes and Aspergillus strains and germ tube inhibition assay was evaluated using Candida albicans. Cell viability was assessed by the MTT assay. The main constituents of the oil are E-anetol (47%), α-phellandrene (11%), α-pinene (10.1%) and fenchone (10.8%). The oil was more active against Cryptococcus neoformans and C. albicans (MICs 0.32-0.64 µL/mL) and the filamentation of C. albicans was totally inhibited with 0.08 µL/mL. The oil is safe for keratinocytes, hepatocytes and fibroblasts in concentrations up to 1.25 µL/mL, and to macrophages up to 0.64 µL/mL. These findings highlight safe bioactive concentrations that should be deeper investigated for further application in pharmaceutical industry.

Oxygenated monoterpenes-rich volatile oils as potential antifungal agents for dermatophytes.

Essential oils (EOs) extracted from Lavandula luisieri and Cymbopogon citratus were tested for their antifungal activity against ten clinical isolates of dermatophytes isolated from cases of tinea pedis. Inhibition of conidial germination and antifungal drug/EO combination assay were tested on two ATCC reference strains of Trichophyton rubrum and Trichophyton mentagrophytes. EOs were characterised by high amount of oxygenated monoterpenes in their composition. Strong antifungal activity was observed for the majority of clinical strains, and fungicidal activity was demonstrated. Positive interaction between L. luisieri EO combined with terbinafine was observed against terbinafine-resistant strain (Tr ATCC MYA-4438). Significative reduction of the germination was observed above 100 µg mL-1. Both oils were safe to macrophage mammalian cells at tested concentration. This study describes the antifungal activity of L. luisieri and C. citratus EOs against dermatophytes, which could be useful in designing new formulations for topical treatments.

Ziziphora tenuior L. essential oil from Dana Biosphere Reserve (Southern Jordan); Chemical characterization and assessment of biological activities.

ETHNOPHARMACOLOGIC RELEVANCE: Ziziphora tenuior L. (Lamiaceae) is a medicinal plant in Jordan, which is included in various antimicrobial, antiseptic, expectorant and wound healing preparations. It is used for the treatment of cough, stomach ache, dysentery, fever, uterus infection, gut inflammation and painful menstruation. AIM OF THE STUDY: The aim of this study was to assess, for the first time, the chemical composition of the essential oil of Z. tenuior originated from southern Jordan and its antifungal effects against several yeasts. Concomitantly, the mechanisms behind the anti-fungal activity against Candida albicans were also disclosed. Since the Z. tenuior traditional uses are related with inflammatory-associated conditions, the putative anti-inflammatory activity of the oil was also unveiled. Importantly, the potential toxicity of pharmacologically active concentrations was screened in different types of mammalian cells. MATERIALS AND METHODS: Z. tenuior essential oil, isolated by hydrodistillation, was analyzed by gas chromatography, gas chromatography-mass spectrometry and 13C nuclear magnetic resonance spectroscopy. Antifungal activity was evaluated against yeasts, dermatophytes and Aspergillus strains. Germ tube inhibition and biofilm formation assays were evaluated using C. albicans. Assessment of cell viability was made by the MTT assay using different types of mammalian cells, including hepatocytes, keratinocytes and macrophages. The in vitro anti-inflammatory potential of the oil was evaluated by measuring nitric oxide production using lipopolysaccharide-stimulated mouse macrophages. RESULTS: Oxygen-containing monoterpenes are the main oil compounds: pulegone (46.8%), p-menth-3-en-8-ol (12.5%), isomenthone (6.6%) and 8-hydroxymenthone (6.2%). The highest antifungal activity was against Cryptococcus neoformans, with a MIC value of 0.16µL/mL. The oil revealed an important inhibitory effect on germ tube formation with a filamentation inhibition rate higher than 80% at 0.16µL/mL. The amount of the attached biomass was reduced. Importantly, concentrations devoid of toxicity on several mammalian cell types still displayed anti-inflammatory activity (0.16 and 0.32µL/mL). CONCLUSIONS: These findings add significant information to the pharmacological activity of Z. tenuior, thus justifying and reinforcing the use of this plant in traditional medicine. Additionally, the antifungal and anti-inflammatory potential of the oil at non-toxic concentrations, opens new avenues for its further exploitation, for instance in health-care product development.

Chemical composition and biological activities of Artemisia judaica essential oil from southern desert of Jordan.

ETHNOPHARMACOLOGIC RELEVANCE: Artemisia judaica L. (Arabic name: Beithran), is a medicinal and aromatic plant growing in the valley bottoms of desert areas, particularly in the southern desert of Jordan nearest to the Jordan-Saudi Arabia borders and in Wadi Araba in the Southern Badia. In Jordan, A. judaica is widely used in traditional medicine being recommended by aboriginal Bedouins in the North Badia region of Jordan as calmative. Furthermore, it is used for the treatment of stomach ache, heart diseases, sexual weakness, diabetes, gastro-intestinal disorders and external wounding. Additionally, other folk medicines of the Arabic region commonly use this aromatic plant for the treatment of inflammatory-related diseases, for instance fungal infections, diabetes, atherosclerosis, cancer and arthritis. AIM OF THE STUDY: Considering the traditional medicinal uses and the lack of scientific studies addressing the cellular and molecular mechanisms behind A. judaica claimed activities, the present study was designed to validate some of the traditional uses ascribed to this species, specifically the antifungal and anti-inflammatory activities of A. judaica essential oil at doses devoid of cytotoxicity to mammalian cells. MATERIALS AND METHODS: Chemical analysis of A. judaica essential oil isolated by hydrodistillation from aerial parts was carried out by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The antifungal activity (minimal inhibitory concentrations and minimal lethal concentrations) was evaluated against yeasts, dermatophyte and Aspergillus strains. In order to deeply explore the mechanisms behind the anti-fungal effect of the essential oil, the germ tube inhibition assay and the biofilms formation assay were evaluated using Candida albicans. The assessment of cell viability was accomplished using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in both hepatocytes and macrophages. Furthermore, the in vitro anti-inflammatory potential of A. judaica oil was evaluated by measuring nitric oxide (NO) production using lipopolysaccharide (LPS)-stimulated mouse macrophages. RESULTS: Oxygen containing monoterpenes are a representative group of constituents (68.7%) with piperitone (30.4%), camphor (16.1%) and ethyl cinnamate (11.0%) as main compounds. The highest antifungal activity of the oil was observed against Cryptococcus neoformans, with a MIC value of 0.16µL/mL. The oil revealed an important inhibitory effect on germ tube formation in C. albicans with 80% inhibition of filamentation at a concentration of 0.16µL/mL. Importantly, the oil also interfered with pre-formed biofilms by reducing the amount of the attached biomass. Furthermore, the essential oil significantly inhibited NO production evoked by LPS on macrophages at concentrations with very low toxicity (0.32µL/mL) or without toxicity (0.16µL/mL) to both macrophages and hepatocytes. CONCLUSIONS: The present study revealed that A. judaica essential oil from Jordan significantly inhibited germ tube formation and disrupted preformed biofilms of C. albicans, emphasizing the therapeutic potential for the treatment of disseminated candidiasis. Additionally, safe concentrations of this essential oil significantly inhibited NO production elicited by LPS in macrophages, highlighting its potential anti-inflammatory activity. Overall, A. judaica bears promising therapeutic potential for further drug development. Importantly, this work also validates some of the traditional uses of A. judaica.

Artemisia herba-alba essential oil from Buseirah (South Jordan): Chemical characterization and assessment of safe antifungal and anti-inflammatory doses.

ETHNOPHARMACOLOGIC RELEVANCE: Artemisia herba-alba Asso ("desert wormwood" in English; "armoise blanche" in French; "shaih" in Arabic), is a medicinal and strongly aromatic plant widely used in traditional medicine by many cultures since ancient times. It is used to treat inflammatory disorders (colds, coughing, bronchitis, diarrhea), infectious diseases (skin diseases, scabies, syphilis) and others (diabetes, neuralgias). In Jordanian traditional medicine, this plant is used as antiseptic and against skin diseases, scabies, syphilis, fever as well as menstrual and nervous disorders. AIM OF THE STUDY: Considering the traditional medicinal uses and the lack of scientific studies addressing the cellular and molecular players involved in these biological activities, the present study was designed to unveil the antifungal and anti-inflammatory activities of A. herba-alba Asso essential oil at doses devoid of toxicity to mammalian cells. MATERIALS AND METHODS: Chemical analysis of A. herba-alba essential oil isolated by hydrodistillation from aerial parts was carried out by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The antifungal activity (minimal inhibitory concentrations and minimal lethal concentrations) was evaluated against yeasts, dermatophyte and Aspergillus strains. In order to explore the mechanisms behind the anti-fungal effect of the essential oil, the germ tube inhibition assay was evaluated using Candida albicans. The assessment of cell viability was accomplished using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the in vitro anti-inflammatory potential of A. herba-alba oil at the periphery and central nervous system was evaluated by measuring nitric oxide (NO) production using lipopolysaccharide (LPS)-stimulated mouse macrophages and microglia, respectively. RESULTS: Oxygen-containing monoterpenes are the main compounds of the oil, namely 1,8-cineole (20.1%), ß-thujone (25.1%), α-thujone (22.9%) and camphor (10.5%). Among the fungal strains tested, the oil demonstrated potential against Trichophyton rubrum and Epidermophyton floccosum, with minimal inhibitory concentration (MIC) and minimal lethal concentration (MCL) values of 0.32 mg/mL and Cryptococcus neoformans with MIC of 0.64 mg/mL. The oil revealed a strong inhibitory effect on germ tube formation in C. albicans with inhibition of filamentation around 90% at a concentration 0.16 mg/mL. Importantly, the essential oil significantly inhibited NO production evoked by LPS without cytotoxicity at concentrations up to 1.25 µL/mL in macrophages and up to 0.32 µL/mL in microglia. Furthermore, evaluation of cell viability in RAW 264.7 macrophages, BW2 microgliacells and HaCaT keratinocytes showed no cytotoxicity at concentrations up to 0.32 µL/mL. CONCLUSIONS: It was possible to find appropriate doses of A. herba-alba oil with both antifungal and anti-inflammatory activities and without detrimental effects towards several mammalian cell types. These findings add significant information to the pharmacological activity of A. herba-alba essential oil, specifically to its antifungal and anti-inflammatory therapeutic value, thus justifying and reinforcing the use of this plant in traditional medicine.

Chemical composition and antibacterial activity of Lavandula coronopifolia essential oil against antibiotic-resistant bacteria.

The aim of this study was to analyse the composition of the essential oil (EO) of Lavandula coronopifolia from Morocco and to evaluate its in vitro antibacterial activity against antibiotic-resistant bacteria isolated from clinical infections. The antimicrobial activity was assessed by a broth micro-well dilution method using multiresistant clinical isolates of 11 pathogenic bacteria: Klebsiella pneumoniae subsp. pneumoniae, Klebsiella ornithinolytica, Escherichia coli, Enterobacter cloacae, Enterobacter aerogenes, Providencia rettgeri, Citrobacter freundii, Hafnia alvei, Salmonella spp., Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus. The main compounds of the oil were carvacrol (48.9%), E-caryophyllene (10.8%) and caryophyllene oxide (7.7%). The oil showed activity against all tested strains with minimal inhibitory concentration (MIC) values ranging between 1% and 4%. For most of the strains, the MIC value was equivalent to the minimal bactericidal concentration value, indicating a clear bactericidal effect of L. coronopifolia EO.

Activity of Thymus capitellatus volatile extract, 1,8-cineole and borneol against Leishmania species.

In the search for new leishmanicidal agents, Thymus capitellatus Hoffmanns. & Link (family Lamiaceae) volatile extract and its major compounds, 1,8-cineole and borneol, were tested against Leishmania infantum, Leishmania tropica and Leishmania major. Plant volatile extract (essential oil) was analysed by GC and GC-MS and the activity of essential oil on Leishmania promastigotes viability was assessed using tetrazolium-dye colorimetric method (MTT). The MTT test was also used to assess the cytotoxicity of essential oil on macrophages and bovine aortic endothelial cells. Effects on parasites were also analyzed by flow cytometry in order to assess mitochondrial transmembrane electrochemical gradient (JC-1), analyze phosphatidylserine externalization (annexin V-FITC, propidium iodide) and evaluate cell cycle (DNase-free, RNase, PI). Morphological and ultrastructural studies were performed by light, scanning and transmission electron microscopy. T. capitellatus volatile extract exhibited anti-parasite activity on Leishmania species, with IC50 values ranging from 35 to 62 µg/ml. However, major compounds 1,8-cineole and borneol did not showed biological activity suggesting that these monoterpenes are not responsible for the antileishmanial activity of T. capitellatus essential oil. Appearance of aberrant-shaped cells, mitochondrial swelling and autophagosomal structures were some of the ultrastructural alterations exhibited among treated promastigote cells. T. capitellatus promoted leishmanicidal effect by triggering a programmed cell death as evidenced by externalization of phosphatidylserine, loss of mitochondrial membrane potential, and cell-cycle arrest at the G(0)/G(1) phase. The volatile extract did not induced cytotoxic effects on mammalian cells. Taken together, these results suggest that T. capitellatus may represent a valuable source for therapeutic control of leishmaniasis in humans and animals.

Essential oil of common sage (Salvia officinalis L.) from Jordan: assessment of safety in mammalian cells and its antifungal and anti-inflammatory potential.

Salvia officinalis L. (Lamiaceae) is a Mediterranean species, naturalized in many countries. In Jordan, it is used in traditional medicine as antiseptic, antiscabies, antisyphilitic, and anti-inflammatory, being frequently used against skin diseases. This study aimed the assessment of the antifungal and anti-inflammatory potential of its essential oils, and their cytotoxicity on macrophages and keratinocytes. The oils were investigated by gas chromatography and gas chromatography-mass spectrometry and the antifungal activity was evaluated against yeasts, dermatophyte and Aspergillus strains. Assessment of cell viability was made by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and the in vitro anti-inflammatory potential was evaluated by measuring nitric oxide production using lipopolysaccharide-stimulated mouse macrophages. The main compounds of S. officinalis oils were 1,8-cineole (39.5-50.3%) and camphor (8.8-25.0%). The oils revealed antifungal activity against dermatophyte strains and significantly inhibited NO production stimulated by LPS in macrophages, without affecting cell viability, in concentrations up to 0.64 µL/mL. This is the first report addressing the in vitro anti-inflammatory potential of S. officinalis oil. These findings demonstrated that bioactive concentrations of S. officinalis oils do not affect mammalian macrophages and keratinocytes viability making them suitable to be incorporated in skin care formulations for cosmetic and pharmaceutical purposes.

Antifungal, antioxidant and anti-inflammatory activities of Oenanthe crocata L. essential oil.

The present study reports the chemical composition, antifungal, antioxidant and anti-inflammatory properties as well as the cytotoxicity of Oenanthe crocata essential oil and one of its main compounds. The essential oil was obtained from the aerial parts of the plant by hydrodistillation and analysed by GC and GC/MS. The oil was predominantly composed of monoterpene hydrocarbons (85.8%), being the main compounds trans-ß-ocimene (31.3%), sabinene (29.0%) and cis-ß-ocimene (12.3%). For the antifungal activity, the minimal inhibitory and minimal lethal concentrations (MICs and MLCs) were determined. The oil was particularly active against dermatophytes and Cryptococcus neoformans, with MIC values ranging from 0.08 to 0.16 µL/mL. Regarding the anti-inflammatory activity, both the oil and sabinene demonstrated strong anti-inflammatory activity through nitric oxide (NO) production inhibition in lipopolysaccharide (LPS) plus interferon gamma (IFN-γ)-triggered macrophages. Furthermore, the essential oil showed a potent NO scavenging effect and inhibited inducible NO synthase expression. Interestingly, and although we detected a cytotoxic effect in macrophages and keratinocytes for the highest concentrations tested of the oil and sabinene, we also disclosed bioactive and safe concentrations to be further explored for therapeutic proposes. Taking together, these results support the use of the oil and sabinene for the management of dermatophytosis and/or inflammatory-related diseases.

Antifungal activity of Ferulago capillaris essential oil against Candida, Cryptococcus, Aspergillus and dermatophyte species.

This study evaluates the composition, antifungal activity and mechanism of action of the essential oil of Ferulago capillaris (Link ex Spreng.) Cout. and its main components, limonene and α-pinene, against clinically relevant yeasts and moulds. Essential oil from the plant's aerial parts was obtained by hydrodistillation and analysed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC-MS). Essential oil showed high contents of limonene (30.9%) and α-pinene (35.8%). Minimum inhibitory concentrations (MICs) were measured according to the reference Clinical and Laboratory Standards Institute (CLSI) broth macrodilution protocols. Cell suspensions were subcultured in solid medium and the minimum fungicidal concentrations (MFCs) were rendered. The effect of essential oil on germ tube formation, mitochondrial function and ergosterol biosynthesis was investigated. Essential oil and α-pinene displayed low and similar MIC and MFC values against tested organisms (0.08 to 5.0 µL/mL), while limonene showed a weaker activity (0.32 to 20 µL/mL). Essential oil inhibited germ tube formation at sub-inhibitory concentrations on Candida albicans. The exposure of C. albicans to the essential oil resulted in impairment of mitochondrial functions in a dose-dependent manner. No difference in ergosterol content was observed in essential oil-treated C. albicans. F. capillaris and α-pinene display a broad fungicidal activity. The fungicidal activity of F. capillaris on C. albicans can be related to an induced oxidative stress which affects enzymes activity and the membrane potential of mitochondria. The essential oil of F. capillaris was shown to have potential for use in the development of clinically useful therapeutic preparations, particularly for topical application in the management of superficial mycoses.

Isolation of the volatile fraction from Apium graveolens L. (Apiaceae) by supercritical carbon dioxide extraction and hydrodistillation: chemical composition and antifungal activity.

Apium graveolens L. (wild celery), belonging to the family of Apiaceae, is a scaposus hemicryptophyte. Instead, the cultivate plant is an annual or biennial herb widely used as a spice and seasoning in food. A broad range of biological activities have been attributed to A. graveolens. These include antimicrobial activity, larvicidal activity, hepatoprotective activity, nematicidal and mosquito repellent potential and antihyperlipidaemic properties.In this study, the authors compare the composition of the volatile fractions of A. graveolens collected in natural populations in Portugal and Italy and evaluate their potential as antifungal agents.The composition of the volatile oils obtained by hydrodistillation and their antifungal activity are reported. The oils were analysed by gas chromatography-flame ionisation detector and gas chromatography-mass spectrometry methods and their composition were compared with that of the volatile extracts isolated by supercritical CO2. A chemical variability in the extracts depending on the origin of the plants and on the extraction method was observed. The results showed the presence of sedanenolide, neocnidilide and neophytadiene as main components. The minimal inhibitory concentration (MIC) and the minimal lethal concentration were used to evaluate the antifungal activity of the oils against Candida albicans, Candida tropicalis, Candida krusei, Candida guilliermondii, Candida parapsilosis, Cryptococcus neoformans, Trichophyton rubrum, Trichophyton mentagrophytes, T. mentagrophytes var. interdigitale, Trichophyton verrucosum, Microsporum canis, Microsporum gypseum, Epidermophyton floccosum, Aspergillus niger, Aspergillus fumigatus and Aspergillus flavus. The oil from Italy rich in neophytadiene is the more active, with MIC values of 0.04-0.64 µL mL(-1). Our results show that A. graveolens volatile extracts may be useful in the clinical treatment of fungal diseases.

Lavandula luisieri essential oil as a source of antifungal drugs.

This work reports the antifungal activity of Lavandula luisieri essential oils against yeast, dermatophyte and Aspergillus strains responsible for human infections and food contamination. The oil's cytotoxicity and its effect on the yeast-mycelium transition in Candida albicans, an important virulence factor, were also evaluated. Analyses by GC and GC/MS showed a peculiar composition of irregular monoterpenes. Significant differences between the samples occurred in the amounts of 1,8-cineole, fenchone and trans-α-necrodyl acetate. The oil with higher amounts of irregular monoterpenes was the most effective. The influence of the oils on the dimorphic transition in C. albicans was also studied through the germ tube inhibition assay. Filamentation was completely inhibited at concentrations sixteen times lower than the minimal inhibitory concentration. The results support the use of L. luiseiri essential oils in the development of new phytopharmaceuticals and food preservatives and emphasise its antifungal properties at concentrations not cytotoxic or with very low detrimental effects on mammalian cells.

Essential oil of Juniperus communis subsp. alpina (Suter) Celak needles: chemical composition, antifungal activity and cytotoxicity.

Essential oils are known to possess antimicrobial activity against a wide spectrum of bacteria and fungi. In the present work the composition and the antifungal activity of the oils of Juniperus communis subsp. alpina (Suter) Celak were evaluated. Moreover, the skin cytotoxicity, at concentrations showing significant antifungal activity, was also evaluated. The oils were isolated by hydrodistillation and analysed by gas chromatography and gas chromatography-mass spectrometry. Minimal inhibitory concentration (MIC) and minimal lethal concentration (MLC) were used to evaluate the antifungal activity of the oil against dermatophytes (Epidermophyton floccosum, Microsporum canis, M. gypseum, Trichophyton mentagrophytes, T. mentagrophytes var. interdigitale, T. rubrum, T. verrucosum), yeasts (Candida albicans, C. guillermondii, C. krusei, C. parapsilosis, C. tropicalis, Cryptococcus neoformans) and Aspergillus species (Aspergillus flavus, A. fumigatus, A. niger). Cytotoxicity was tested in HaCaT keratinocytes through the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Essential oil of J. communis subsp. alpina needles was predominantly composed of monoterpene hydrocarbons (78.4%), with the main compounds being sabinene (26.2%), α-pinene (12-9%) and limonene (10.4%). Results concerning the antifungal activity demonstrated the potential of needle oil against dermatophytes, particularly for Microsporum canis and Trichophyton rubrum with MIC and MLC of 0.32 µL/mL. Furthermore, evaluation of cell viability showed no significant cytotoxicity in HaCaT keratinocytes at concentrations between 0.32 and 0.64 µL/mL. These results show that it is possible to find appropriate doses of J. communis subsp. alpina oil with both antifungal activity and a very low detrimental effect on keratinocytes.

The anti-Candida activity of Thymbra capitata essential oil: effect upon pre-formed biofilm.

ETHNOPHARMACOLOGICAL RELEVANCE: [corrected] Thymbra capitata essential oil is traditionally considered to exhibit powerful antiseptic properties, thus being used to treat cutaneous infections. The aim of the present study was to evaluate the effect of Thymbra capitata essential oil upon pre-formed biofilm of different Candida strains while comparing it with the activity against planktonic cells. MATERIALS AND METHODS: Fifteen Candida isolates were included, corresponding to clinical and collection type strains. Essential oil was obtained by hydrodistillation and its composition analysed by GC/MS. Activity upon planktonic cells was evaluated according to M27-A3 macromethod. Its effect upon 24h preformed biofilm biomass was determined using the crystal violet procedure and the metabolic activity was studied applying the XTT/menadione technique. RESULTS: Biofilm biomass and metabolic activity of all tested species were reduced up to 50% at MIC values. The effect was more pronounced at double MIC values, achieving >80% reduction, except for Candida albicans that presented a more resistant profile (62%). CONCLUSION: Thymbra capitata essential oil presented an important effect upon Candida biofilms. It is proposed as a valuable antifungal product to be used in an appropriate pharmaceutical formulation for the management of resistant mucocutaneous candidosis.