Chemical composition and antimicrobial activity of cumin oil (Cuminum cyminum, Apiaceae)

Cumin oil samples (Cuminum cyminum L.) from four different geographical origins were analyzed using GC-MS and GC-FID for their qualitative and quantitative composition. The major compounds in all cumin oils were the monoterpenes beta-pinene, p-cymene and gamma-terpinene and the terpenoid aldehydes cuminic aldehyde and the isomeric menthadien carboxaldehydes. All essential oils, and cuminic aldehyde, were tested, using agar diffusion and serial dilution methods, against different Gram-positive and Gram-negative bacteria isolated from different sources of food (pork fillet, minced meat and sausages) and clinical isolates, as well as three different Candida albicans isolates. All cumin oils and cuminic aldehyde exhibited a considerable inhibitory effect against all the organisms tested, except Pseudomonas spp.

Chemical Composition and Antimicrobial Activity of Cumin Oil (Cuminum Cyminum, Apiaceae)

Cumin oil samples ( Cuminum cyminum L.) from four different geographical origins were analyzed using GC-MS and GC-FID for their qualitative and quantitative composition. The major compounds in all cumin oils were the monoterpenes β-pinene, p-cymene and γ-terpinene and the terpenoid aldehydes cuminic aldehyde and the isomeric menthadien carboxaldehydes. All essential oils, and cuminic aldehyde, were tested, using agar diffusion and serial dilution methods, against different Gram-positive and Gram-negative bacteria isolated from different sources of food (pork fillet, minced meat and sausages) and clinical isolates, as well as three different Candida albicans isolates. All cumin oils and cuminic aldehyde exhibited a considerable inhibitory effect against all the organisms tested, except Pseudomonas spp.

Antimicrobial activities of single aroma compounds

Commercially available aroma samples were evaluated for their olfactory quality by professional perfumers and tested for their antimicrobial activity. Agar diffusion and agar-dilution were used as test methods and a set of two Gram-positive (Staphylococcus aureus and Enterococcus faecalis) and four Gram-negative bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris G, Klebsiella pneumoniae and Salmonella abony) and a yeast, Candida albicans, were the test microorganisms. All the investigated compounds were active against Gram-positive bacteria, especially beta-caryophyllene against Enterococcus faecalis (MIC 6 ppm), but only few substances showed activity towards Gram-negative bacteria, except for cinnamic acid, which was active against all (MIC 60 ppm) and Candida albicans, against which cinnamic acid and caryophyllene oxide showed high activity (MIC < 60 ppm).

Chemical composition, olfactory evaluation and antimicrobial activity of selected essential oils and absolutes from Morocco

The chemical compositions of selected essential oils from North Africa, especially Morocco, of geranium, wild Moroccan chamomile and rosemary as well as absolutes of rose and geranium were determined using GC/FID and GC/MS. These oils and absolutes were tested concerning their antimicrobial activity against some food spoilage strains obtained from fresh milk and minced meat products, like sausages and pork fillet, in accordance with ISO testing procedures. Gram-positive (Bacillus cereus and Staphylococcus aureus) and Gram-negative (Escherichia coli, Salmonella abony and Pseudomonas aeruginosa) strains were used, as well as the yeast Candida albicans. Using a serial broth dilution method, all samples demonstrated weak antimicrobial activity against the Gram-negative bacteria and the yeast, compared with the activity towards the Gram-positive bacteria.

Antimicrobial Activities of Single Aroma Compounds

Commercially available aroma samples were evaluated for their olfactory quality by professional perfumers and tested for their antimicrobial activity. Agar diffusion and agar-dilution were used as test methods and a set of two Gram-positive ( Staphylococcus Aureus and Enterococcus faecalis) and four Gram-negative bacterial strains ( Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris G, Klebsiella pneumoniae and Salmonella abony) and a yeast, Candida albicans, were the test microorganisms.

All the investigated compounds were active against Gram-positive bacteria, especially β-caryophyllene against Enterococcus faecalis (MIC 6 ppm), but only few substances showed activity towards Gram-negative bacteria, except for cinnamic acid, which was active against all (MIC 60 ppm) and Candida albicans, against which cinnamic acid and caryophyllene oxide showed high activity (MIC < 60 ppm).

Chemical composition, olfactory evaluation and antioxidant effects of essential oil from Mentha x piperita

The chemical composition of the essential oil from peppermint (Mentha x piperita L.) was analyzed by GC/FID and GC-MS. The main constituents were menthol (40.7%) and menthone (23.4%). Further components were (+/-)-menthyl acetate, 1,8-cineole, limonene, beta-pinene and beta-caryophyllene. Peppermint oil possessed antiradical activity with respect to DPPH (diphenyl picryl hydrazyl) and hydroxyl (OH*) radicals, exercising stronger antioxidant impact on the OH* radical. The concentrations required for 50% inhibition of the respective radical (IC50) were 860 microg/mL for DPPH and 0.26 microg/mL for OH*. Peppermint essential oil demonstrated antioxidant activity in a model linoleic acid emulsion system in terms of inhibiting conjugated dienes formation by 52.4% and linoleic acid secondary oxidized products generation by 76.9% (at 0.1% concentration).

Chemical Composition, Olfactory Evaluation and Antioxidant Effects of Essential Oil from Mentha x piperita

The chemical composition of the essential oil from peppermint ( Mentha x piperita L.) was analyzed by GC/FID and GC-MS. The main constituents were menthol (40.7%) and menthone (23.4%). Further components were (+/-)-menthyl acetate, 1,8-cineole, limonene, β-pinene and β-caryophyllene. Peppermint oil possessed antiradical activity with respect to DPPH (diphenyl picryl hydrazyl) and hydroxyl (OH•) radicals, exercising stronger antioxidant impact on the OH• radical. The concentrations required for 50% inhibition of the respective radical (IC50) were 860 μg/mL for DPPH and 0.26 μg/mL for OH•. Peppermint essential oil demonstrated antioxidant activity in a model linoleic acid emulsion system in terms of inhibiting conjugated dienes formation by 52.4% and linoleic acid secondary oxidized products generation by 76.9% (at 0.1% concentration).

Chemical Composition, Olfactory Evaluation and Antioxidant Effects of Essential Oil from Mentha Canadensis

The chemical composition of the essential oil from cornmint ( Mentha canadensis L.) was analyzed by GC/FID and GCMS. The main constituents were menthol (41.2%) and menthone (20.4%). It was established that cornmint oil had antiradical activity with respect to the DPPH and hydroxyl (OH•) radicals. The concentrations necessary for 50% neutralization of the respective radicals (IC50) were 365.0 μg/mL for DPPH and 0.3 μg/mL for OH•, which was indicative that the antioxidant activity in terms of OH• was higher than that of quercetin. Cornmint oil chelated the Fe3+ ions present in the solution. The oil demonstrated antioxidant activity in a linoleic acid emulsion model system, where at 0.1% concentration it inhibited the formation of conjugated dienes by 57.1% and the generation of secondary oxidized products of linoleic acid by 76.1%.

Chemical composition, olfactory evaluation and antioxidant effects of essential oil from Mentha canadensis

The chemical composition of the essential oil from cornmint (Mentha canadensis L.) was analyzed by GC/FID and GC-MS. The main constituents were menthol (41.2%) and menthone (20.4%). It was established that cornmint oil had antiradical activity with respect to the DPPH and hydroxyl (OH*) radicals. The concentrations necessary for 50% neutralization of the respective radicals (IC50) were 365.0 microg/mL for DPPH and 0.3 microg/mL for OH*, which was indicative that the antioxidant activity in terms of OH* was higher than that of quercetin. Cornmint oil chelated the Fe3+ ions present in the solution. The oil demonstrated antioxidant activity in a linoleic acid emulsion model system, where at 0.1% concentration it inhibited the formation of conjugated dienes by 57.1% and the generation of secondary oxidized products of linoleic acid by 76.1%.

Chemical Composition, Olfactory Evaluation and Antioxidant Effects of the Essential oil of Origanum Majorana L. from Albania

The chemical composition of marjoram essential oil ( Origanum majorana L.) was determined by GC/FID and GC/MS. As major compounds of the oil terpinen-4-ol (21.3%), trans-sabinene hydrate (15.5%), γ-terpinene (14.0%), and α-terpinene (8.9%) were identified. The odour profile and evaluation of marjoram essential oil was established.

Marjoram oil has antiradical activity with regard to DPPH, exceeding that of the phenolic component thymol. The oil exhibited scavenging effect on the hydroxyl radicals (OH•), as well, which substantially exceeded that towards the DPPH radical - the respective concentrations for 50% inhibition of the radicals (IC50) were 0.11μg/mL for OH• and 341.0μg/mL for DPPH.

Marjoram essential oil was capable of antioxidant activity in a linoleic acid emulsion model system, where at concentration of 0.05% it inhibited conjugated dienes formation by 50.00% and the generation of linoleic acid secondary oxidized products by 79.85%.

Chemical Composition, Olfactory Evaluation and Antioxidant Effects of an Essential Oil of Thymus Vulgaris L. from Germany

The composition of an essential oil of thyme from Germany was analyzed by GC/FID and GC-MS. Thirty constituents were identified with thymol (49.6%), p-cymene (16.4%), γ-terpinene (8.0%), linalool (4.6%) and carvacrol (4.0%) as the main compounds. In addition, olfactory evaluations were made of the thyme sample, as well as correlations of odor-impressions of the single constituents with published data. A pleasant aroma, characteristic of thyme oils was determined, with some main and minor constituents as odor-active compounds.

The thyme oil possessed antiradical activity with respect to DPPH, which was greater than the activities of its major individual phenolic components, carvacrol and thymol. The oil also demonstrated a scavenging effect with respect to hydroxyl radicals (OH•), exceeding the effect exercised on the DPPH radical, the respective concentrations resulting in a 50% inhibition (IC50) being 41.4 μg/mL for DPPH and 2.9 μg/mL for OH•. Scavenging of the superoxide radical at a concentration of 50 μg/mL was 76.9%. Thyme essential oil revealed antioxidant activity in a model system comprised of a linoleic acid emulsion where, at a concentration of 0.05%, it caused 59.5% inhibition of conjugated dienes formation and 72.4% inhibition of the generation of secondary oxidized products from linoleic acid.

Chemical Composition, Olfactory Evaluation and Antioxidant Effects of the Essential Oil of Satureja Montana L

The composition of an essential oil of savory ( Satureja montana L.) from Slovenia was determined by GC/FID and GC-MS; the major components were carvacrol (41.5%), p-cymene (11.0%), thymol (8.6%), γ-terpinene (6.2%) and β-caryophyllene (4.1%). Using olfactory evaluations of the oil, a characteristic odor with strong carvacrol and thymol-notes was found.

Savory oil was capable of antiradical activity with respect to the DPPH, hydroxyl (OH•), and superoxide radicals. The concentrations sufficient for 50% neutralization (IC50) of the respective radicals were 18.7 μg/mL for DPPH and 0.0067 μg/mL for OH•. The neutralization of the superoxide radical at a concentration of 50 μg/mL was by 78.8%. The antiradical activity of savory oil with regard to the DPPH and OH• radicals was substantially greater than that of its major phenolic components, carvacrol and thymol. Savory essential oil demonstrated antioxidant activity in a model system comprised of linoleic acid emulsion, inhibiting at a concentration of 0.01% the conjugated dienes formation by 64.5% and the generation of linoleic acid secondary oxidized products by 73.3%.

Comparative Evaluation of Antimicrobial Activity and Composition of Rose Oils from Various Geographic Origins, in Particular Bulgarian Rose Oil

In the present study we evaluated the composition and antimicrobial activity of various rose oils from Bulgaria, Turkey, Morocco, Iran and China against three Gram-positive, three Gram-negative bacteria and two yeasts. The composition of the studied essential oils was determined by GC and GC/MS. Citronellol was the major compound of all the oil samples: 31.7% (Chinese oil); 32.6% (Iranian oil); 33.6% (Moroccan oil); 34.9% (Bulgarian oil) and 38,7 % (Turkish oil). For the Bulgarian oil we could determine the highest activity against all microorganisms. Bacillus cereus ATCC 11778 was the most sensitive strain to Bulgarian rose oil (MCC 128 μg/mL) and Pseudomonas aeruginosa ATCC 9627 and P. fluorescens were more resistible strains (MCC 4096 μg/mL). Antimicrobial activity of rose oils is mainly due to the action of oxygenated acyclic monoterpenes citronellol, geraniol, nerol and linalool, their acetate derivatives and the phenolic compound eugenol.

GC-MS-Analysis, Antimicrobial Activities and Olfactory Evaluation of Essential Davana (Artemisia pallens Wall. ex DC) Oil from India

An essential oil sample of davana (Artemisia pallens Wall. ex DC.) and a fraction thereof were investigated for their chemical composition using GC and GC-MS. cis-Davanone (45.8%), bicyclogermacrene (9.6%), linalool (2.5%), caryophyllene oxide (2.2%) and phytol (2.1%) were found to be the main constituents of the davana oil sample. The main constituents of the fraction were analyzed as cis-davanone (72.2%), davana ether 2° (5.2%) and ( Z)-ethyl cinnamate (5.2%). Antimicrobial activities of the essential oil, the fraction, some major and reference compounds were evaluated against seven strains of bacteria and one yeast using agar diffusion and agar dilution methods. The davana essential oil showed antimicrobial activities against Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica subsp. enterica and the yeast Candida albicans; the davana fraction was effective against all the tested bacteria and yeast except Pseudomonas aeruginosa and Proteus vulgaris. The oil and the fraction were also olfactorially evaluated.

Chemical Composition, Olfactory Evaluation and Antioxidant Effects of an Essential Oil of Origanum Vulgare L. from Bosnia

The chemical composition of an essential oil of oregano ( Origanum vulgare L.) from Bosnia was analyzed by GC/FID and GC-MS. In total, 33 constituents were identified and carvacrol (66.2%), p-cymene (9.1%), γ-terpinene (7.3%) and β-caryophyllene (4.1%) were found to be the main compounds. In addition, olfactory evaluation data of the sample and correlations with the odor attributes of the single components are presented to explain the complex aroma impression of this essential oil.

The oil possessed antiradical activity with respect to DPPH radicals, exceeding that of its major phenolic component, carvacrol. The oil also revealed scavenging potential with respect to hydroxyl radicals (OH•), which was superior to that towards the DPPH radical; the respective concentrations needed for 50% inhibition (IC50) were 53.8 μg/mL for DPPH and 0.31 μg/mL for OH•. The superoxide scavenging activity of oregano oil was 82.7% at 50 μg/mL. The oil also demonstrated antioxidant activity in a linoleic acid emulsion model system; at 0.05% concentration it inhibited conjugated dienes formation by 69.0% and the generation of secondary oxidized products from linoleic acid by 73.1 %.

Chemical composition and antioxidant properties of clove leaf essential oil

The antioxidant activity of a commercial rectified clove leaf essential oil (Eugenia caryophyllus) and its main constituent eugenol was tested. This essential oil comprises in total 23 identified constituents, among them eugenol (76.8%), followed by beta-caryophyllene (17.4%), alpha-humulene (2.1%), and eugenyl acetate (1.2%) as the main components. The essential oil from clove demonstrated scavenging activity against the 2,2-diphenyl-1-picryl hydracyl (DPPH) radical at concentrations lower than the concentrations of eugenol, butylated hydroxytoluene (BHT), and butylated hydroxyanisole (BHA). This essential oil also showed a significant inhibitory effect against hydroxyl radicals and acted as an iron chelator. With respect to the lipid peroxidation, the inhibitory activity of clove oil determined using a linoleic acid emulsion system indicated a higher antioxidant activity than the standard BHT.

Antimicrobial testinas and gas chromatoaraphic analvsis of pure oxvaenated monoterpenes 1.8-cineole, α-terpineol, terpinen-4-ol and camphor as well as target comoounds in essential oils of pine (Pinus pinaster), rosemary (Rosmarinus officinalis), tea tree (Melaleuca alternifolia)

The oxygenated monoterpenes 1,8-cineole, α-terpineol, terpinen-4-ol and camphor as well as essential oils of pine, rosemary and tea tree, rich in these volatiles, were tested for their antimicrobial activities against some different strains of yeast, Gram-(-)- and Gram-(+)-bacteria by agar diffusion and agar dilution method, respectively. The same was done using the phenolic aroma compound eugenol as a reference-substance. The monoterpene alcohols a-terpineol and terpinen-4-ol were found to be active against all strains used in a wide range. The same result was obtained for the testings of essential oils of pine, rosemary (2 samples) and tea tree. Nearly all aroma chemicals and essential oils did show a significant high antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. For qualitative and quantitaive investigations of the key aroma compounds and the compositions of the essential oils, gas chromatographic methods (GC-FID and GCMS with columns of different polarities) were used and the results correlated with that of the antimicrobial testings. The obtained data are discussed to get more insight into the influence of pure aroma compounds on antimicrobial activities of essential oils.