Characterization of essential oils from lamiaceae species by fourier transform Raman spectroscopy

The Fourier transform Raman (FT-Raman) spectra of pure terpenes and essential oils obtained by hydrodistillation of some Lamiaceae species, are presented. This study shows that principal components of an essential oil can be recognized by FT-Raman. Components predicted by FT-Raman spectrum of an essential oil correlate well with those found as major constituents by GC-MS. In this way the basic chemical character of an essential oil can be recognized. The results demonstrate that certain Raman intensities can be correlated to specific terpenes and therefore FT-Raman can discriminate between the essential oils of which main components belong to different classes of compounds.     

Allelopathic effect of some essential oils and components on germination of weed species

Abstract

In this study, allelopathic effects of some essential oil plants (Carum carvi L., Coriandrum sativum L., Foeniculum vulgare Mill., Lavandula stoechas L., Mentha spicata L.,Origanum onites L., Pimpinella anisum L., Rosmarinus officinalis L., Salvia officinalis L. and Thymbra spicata L.) were investigated against some common weed species (Alcea pallida Waldst. & Kit., Amaranthus retroflexus L., Centaurea salsotitialis L., Raphanus raphanistrum L., Rumex nepalensis Spreng., Sinapis arvensis L. and Sonchus oleraceus L.) that grow in field and horticultural crops. Different concentrations (3, 6, 10 and 20 µl) of the essential oils were tested against weed seeds in vitro and their effect on germination was determined. Inhibitory effects of essential oils and concentrations were analysed with Freadman's test and they were found significant. Essential oils from Carum carvi, Mentha spicata, Origanum onites and Thymbra spicata showed high inhibitory effect against weed seeds at lower concentrations. The main components (carvacrol, thymol, carvone, limonene) of these four essential oils were tested for seed germination at four different concentrations (500, 250, 125 and 62.5 µg/ml) against the same weeds.Thymol, carvacrol and carvone showed high inhibition even at low concentrations against weed seeds. Only Alcea pallida seeds showed resistance against all essential oils and components.     

Characterization of the volatile composition of essential oils of some lamiaceae spices and the antimicrobial and antioxidant activities of the entire oils

The essential oils of Ocimum basilicum L., Origanum vulgare L., and Thymus vulgaris L. were analyzed by means of gas chromatography-mass spectrometry and assayed for their antioxidant and antimicrobial activities. The antioxidant activity was evaluated as a free radical scavenging capacity (RSC), together with effects on lipid peroxidation (LP). RSC was assessed measuring the scavenging activity of the essential oils on 2,2-diphenyl-1-picrylhydrazil (DPPH(*)) and OH(*) radicals. Effects on LP were evaluated following the activities of essential oils in Fe(2+)/ascorbate and Fe(2+)/H(2)O(2) systems of induction. Essential oils exhibited very strong RSCs, reducing the DPPH radical formation (IC(50)) in the range from 0.17 (oregano) to 0.39 microg/mL (basil). The essential oil of T. vulgaris exhibited the highest OH radical scavenging activity, although none of the examined essential oils reached 50% of neutralization (IC(50)). All of the tested essential oils strongly inhibited LP, induced either by Fe(2+)/ascorbate or by Fe(2+)/H(2)O(2). The antimicrobial activity was tested against 13 bacterial strains and six fungi. The most effective antibacterial activity was expressed by the essential oil of oregano, even on multiresistant strains of Pseudomonas aeruginosa and Escherichia coli. A significant rate of antifungal activity of all of the examined essential oils was also exhibited.     

Antioxidant properties of aqueous extracts from selected lamiaceae species grown in Turkey

Water-soluble extracts from black thyme (Thymbra spicata L.), savory (Satureja cuneifolia Ten.), Spanish oregano (Coridothymus capitatus (L.) Reichb. f.), sweet marjoram (Majorana hortensis Moench), Syrian oregano (Origanum syriacum L.), Toka oregano (Origanum minutiflorum O. Schwarz et P. H. Davis), and Turkish oregano (Origanum onites L.) were screened for antioxidant properties in a battery of six in vitro assays. Total phenol content and qualitative-quantitative compositional analyses were also carried out. The extracts demonstrated varying degrees of efficacy in each screen. The savory extract was the most effective at reducing iron(III), scavenging 1,1-diphenyl-2-picrylhydrazyl radicals, inhibiting ascorbate-iron(III)-catalyzed hydroxyl radical-mediated brain phospholipid peroxidation, and site-specific hydroxyl radical-mediated 2-deoxy-d-ribose degradation. The Syrian oregano extract was the most effective chelator of iron(II), while Spanish and Turkish oregano extracts were the most effective inhibitors of nonsite-specific hydroxyl radical-mediated 2-deoxy-d-ribose degradation. All the extracts contained Folin-Ciocalteu reagent-reactive substances, which was confirmed by the presence of polar phenolic analytes (i.e., hydroxybenzoates, hydroxycinnamates, and flavonoids).     

Essential oils from plants and in vitro shoots of Hypericum androsaemum L

The essential oil yields obtained by hydrodistillation of the aerial parts of Hypericum androsaemum cultivated plants varied from 0.94 to 4.09 mg/g of biomass dry weight, depending of the harvest time. The respective analyses performed by gas chromatography and gas chromatography-mass spectrometry revealed more than 80 compounds, 72 of which were identified. Most of the compounds were sesquiterpene hydrocarbons, which, depending of the harvest time, corresponded to 43-78% of the total essential oil. The other compounds were distributed as monoterpene hydrocarbons, oxygen-containing sesquiterpenes, n-alkanes, 1-alkenes, and oxygen-containing monoterpenes, these being a minor group. In H. androsaemum in vitro shoots, sesquiterpene hydrocarbons represented >80% of the respective essential oil. Differences in the essential oil composition were found depending on the harvest time and origin, in vivo versus in vitro, of the plant material. The essential oil sampled in November was characterized by the highest levels of sesquiterpene hydrocarbons and a high number of n-alkanes and 1-alkenes, from C(18) to C(28), whereas that sampled in June of the following year showed the highest levels of n-nonane and 1-octene as well as monoterpene hydrocarbons, the second most representative group.     

Effects of urease inhibitors on germination of seeds in soil

Abstract

The effects of 23 urease inhibitors on germination of seeds in soil were investigated. The urease inhibitors tested were 2/5‐dimethyl‐l,4‐benzoquinone, 1/4‐benzoquinone, hydroquinone, 2,5‐dichloro‐l,4‐benzoquinone, phenylmercuric acetate, catechol, phenylphosphorodiamidate, phosphoric triamide, N‐(4‐nitrophenyl)‐phosphoric triamide, N‐(diaminophosphinyl)benzeneacetamide, 4‐chloro‐N‐(diaminophosphinyl)benzamide, N‐3‐(trifluoromethyl‐phenyl)phosphoric triamide, 4‐fluoro‐N‐(diaminophosphinyl)‐benzamide/ 4‐cyano‐N‐(diaminophosphinyl)benzamide, N‐(diamino‐phosphinyl)‐3‐pyridinecarboxamide, N‐(diaminophosphinyl)‐benzamide, N‐phenylphosphoric triamide, phosphorodiamidic acid, N‐(n‐butyl)thiophosphoric triamide, thiophosphoric triamide, 4‐chlorophenylphosphorodiamidate, 2,4‐diphenoxy‐2,4,6,6‐tetraaminocyclotriphosphazene, and 2‐phenoxy‐2,4,4,6,6‐pentaaminocyclotriphosphazene. Germination tests were performed with seeds of alfalfa (Medicago sativa L.), wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), sorghum [Sorghum bicolor (L.) Moench], and corn (Zea mays L.).

None of the inhibitors tested affected seed germination when applied at the rate of 250 μg g^‐1 soil. One inhibitor (2,5‐dimethyl‐l,4‐benzoquinone) affected seed germination when applied at the rate of 500 μg g^‐1 soil, and three inhibitors (2,5‐dimethyl‐1,4‐benzoquinone, 1,4‐benzoquinone, and hydroquinone) affected seed germination when applied at the rate of 2500 μg g^‐1 soil. None of the other inhibitors tested affected seed germination when applied at the rate of 500 or 2500 μg g^‐1 soil.     

Incorporation of winter grasses suppresses summer weed germination and affects inorganic nitrogen in flooded paddy soil

ABSTRACT

Laboratory experiments were conducted to investigate how incorporation of the winter grasses foxtail (Alopecurus aequalis) and milk vetch (Astragalus sinicus) into flooded paddy soil affects the germination of summer weeds and soil inorganic nitrogen (N) levels. Polyethylene terephthalate (PET) vessels (10.0 × 8.0 × 15.0 cm) were filled with 0.7 kg air-dried soil that had been collected from organic paddy fields located in Tochigi, Japan. Foxtail and milk vetch were then independently incorporated into the soil at rates of 0% (untreated control), 0.25%, 0.5%, 1%, and 1.5%, with four repetitions per treatment. The PET vessels were placed in a growth chamber (Biotron) set to day/night temperatures and humidities of 27/18°C and 70%/65%, respectively, and with an illuminance of 40,000 lx (12 h) for 28 days, and the total number of weeds and changes in the electrical conductivity (EC) of the surface water were investigated throughout this period, while changes in soil inorganic N were determined at the ends of the experiments. The incorporation of both foxtail and milk vetch significantly suppressed the germination of summer weeds by 56% and 50%, respectively, at incorporation rates of 1% and by 78% and 77%, respectively, at incorporation rates of 1.5% compared with their respective controls. There was a high and significant positive correlation between both the rate of winter grass incorporation and the degree of growth suppression and EC. Incorporation of foxtail at rates of 0.25% and 0.5% significantly increased the inorganic N contents of the sub-layer by an average of 68% compared with the control but had no significant effect in the top layer, whereas the incorporation of milk vetch at a rate of 1% significantly increased the inorganic N contents of both the top layer and sub-layer by 200% and 316%, respectively, compared with the control. Furthermore, the effect of milk vetch on inorganic N significantly increased with an increase in the rate of incorporation. These findings demonstrate that incorporation of the winter grasses foxtail and milk vetch into flooded organic paddy soil can suppress weed growth and act as a source of inorganic N.     

Glabrene and isoliquiritigenin as tyrosinase inhibitors from licorice roots

Tyrosinase is known to be a key enzyme in melanin biosynthesis, involved in determining the color of mammalian skin and hair. Various dermatological disorders, such as melasama, age spots, and sites of actinic damage, arise from the accumulation of an excessive level of epidermal pigmentation. The inadequacy of current therapies to treat these conditions as well as high cytotoxicity and mutagenicity, poor skin penetration, and low stability of formulations led us to seek new whitening agents to meet the medical requirements for depigmenting agents. The inhibitory effect of licorice extract on tyrosinase activity was higher than that expected from the level of glabridin in the extract. This led us to test for other components that may contribute to this strong inhibitory activity. Results indicated that glabrene and isoliquiritigenin (2',4',4-trihydroxychalcone) in the licorice extract can inhibit both mono- and diphenolase tyrosinase activities. The IC(50) values for glabrene and isoliquiritigenin were 3.5 and 8.1 microM, respectively, when tyrosine was used as substrate. The effects of glabrene and isoliquiritigenin on tyrosinase activity were dose-dependent and correlated to their ability to inhibit melanin formation in melanocytes. This is the first study indicating that glabrene and isoliquiritigenin exert varying degrees of inhibition on tyrosinase-dependent melanin biosynthesis, suggesting that isoflavenes and chalcones may serve as candidates for skin-lightening agents.     

Effects of nitrification inhibitors on germination of various seeds in soil

Summary The effects of 19 nitrificiation inhibitors on germination of seeds in soil were investigated. The nitrification inhibitors tested were sodium azide, potassium azide, potassium ethyl xanthate, nitrapyrin (N-Serve), etridiazole (Dwell), 3-mercapto-1,2,4-triazole (MT), 2-amino-4-chloro-6-methylpyrimidine (AM), 2,4-diamino-6-trichloromethyl-s-triazine, 2-mercaptobenzothiazole (MBT), 4-amino-1,2,4-triazole (ATC), sodium thiocarbonate (STC), guanylthiourea (ASU), thiourea (TU), dicyandiamide (DCD), sulfathiazole (STC), phenylacetylene, 2-ethynyl-pyridine, 3-methylpyrazole-l-carboxamide (MPC), and ammonium thiosulfate (ATS). Germination tests were performed with seeds of alfalfa (Medicago sativa L.), wheat (Triticum aestivum L.), rye (Secale cereale L.), barley (Hordeum vulgare L.), sorghum [Sorghum bicolor (L.) Moench], oats (Avena sativa L.), and corn (Zea mays). Only 2 of the 19 nitrification inhibitors studied (potassium azide and sodium azide) reduced germination of the seeds tested when applied at the rate of 12.5 g g^–1. The other inhibitors studied had no effect on the germination of wheat, alfalfa, barley, corn, oat, rye, or sorghum seeds when they were applied at the rate of 125 g g^–1 soil, and most of them had no effect on seed germination when applied at the rate of 625 g g^–1 soil.     

Essential oils produced by in vitro shoots of sage (Salvia officinalis L.)

In vitro shoots of sage (Salvia officinalis L.) were established under eight different hormonal supplementations and proliferated by subculture of nodal shoot segments. The respective essential oils, obtained by hydrodistillation, were composed of more than 75 compounds, 65 of which were identified. The 10 major compounds were, by order of retention time, alpha-pinene (4.1-5.4%), camphene (6-7.1%), beta-pinene (9.3-14.5%), limonene (2-2.3%), 1,8-cineole (3.6-5.6%), (-)-thujone (13.2-16.1%), (+)-isothujone (6.6-7.4%), camphor (19.8-24%), alpha-humulene (5.1-6.8%), and manool (4.2-7.7%). Notwithstanding the eight different hormonal supplementations tested, the percentage composition of the shoot essential oils were kept in a narrow range of variation. However, the type and concentration of growth regulators apparently influenced the accumulation of essential oils. The highest accumulation of essential oils and the highest shoot biomass growth were obtained with 2.0 mg/L kinetin and 0.05 mg/L 2,4-dichlorophenoxyacetic acid.     

蛋白质合成抑制剂对萌发玉米超弱光子辐射的影响

为了揭示种子萌发过程中超弱光子辐射机理,分别采用蛋白质合成的转录抑制剂放线菌素D(actinomyin D,AMD)和翻译抑制剂环己亚胺酮(cycloheximide,CHM)处理萌发玉米种子,研究了玉米萌发过程中鲜质量的变化以及自发光子辐射和外界光诱导的延迟光子辐射的变化。结果表明,50μg/m L的AMD部分抑制了萌发玉米鲜质量的增长,100μg/m L的CHM完全抑制了萌发玉米鲜质量的增长,萌发玉米自发光子辐射强度的增长与种子鲜质量的增长呈现正相关(相关系数r分别为0.95492、0.93218和0.96235)。研究还发现,在玉米萌发过程中,AMD和CHM对延迟光子辐射的增长有不同的抑制作用,CHM部分抑制了延迟光子辐射的初始光子数、相干时间和积分强度的增大,AMD则使初始光子数、相干时间和积分强度不再增加。研究结果为揭示种子萌发过程中超弱光子辐射的机理及其技术开发提供参考。     

Peptides derived from atlantic salmon skin gelatin as dipeptidyl-peptidase IV inhibitors

The dipeptidyl-peptidase IV (DPP-IV)-inhibitory activity of peptides derived from Atlantic salmon skin gelatin hydrolyzed by alcalase (ALA), bromelain (BRO), and Flavourzyme (FLA) was determined. The FLA hydrolysate with the enzyme/substrate ratio of 6% showed the greatest DPP-IV-inhibitory activity. The hydrolysate was fractionated by ultrafiltration with 1 and 2.5 kDa cutoff membranes, and the <1 kDa fraction had the highest DPP-IV-inhibitory activity with an IC(50) value of 1.35 mg/mL. The F-1 fraction further isolated by HPLC showed the IC(50) value against DPP-IV of 57.3 μg/mL, and the peptide sequences were identified as Gly-Pro-Ala-Glu (372.4 Da) and Gly-Pro-Gly-Ala (300.4 Da). The synthetic peptides showed dose-dependent inhibition effects on DPP-IV with IC(50) values of 49.6 and 41.9 μM, respectively. The results suggest that the peptides derived from Atlantic salmon skin gelatin would be beneficial ingredients for functional foods or pharmaceuticals against type 2 diabetes.     

Carbon and nitrogen mineralisation from green manures as alternative nitrogen sources in Mediterranean farming

The soil incorporation of green manures is a practice that can be used in sustainable agriculture and in organic farming, where nitrogen (N) sources are limited. The aim of this study was to evaluate balansa clover (Trifolium michelianum Savi), yellow lupine (Lupinus luteus L.) and ryegrass (Lolium multiflorum Lam.) as potential alternative N sources. A total of nine treatments were considered in this study: control, aerial of balansa clover, roots of balansa clover, aerial of yellow lupine, roots of yellow lupine, aerial of ryegrass, roots of ryegrass, mixture aerial + roots of yellow lupine and mixture aerial + roots of ryegrass. A laboratory incubation experiment was conducted under controlled conditions during 196 days and carbon and N mineralisation were followed. Results showed that green manures are appropriate N sources for Mediterranean farming. No significant differences in terms of N mineralisation were observed between aerial or roots biomass of the green manures. Besides, 37–55% of total N applied was mineralised in treatments amended with balansa clover or yellow lupine, whereas 13–21% of total N applied was mineralised in ryegrass. It can be concluded that the most efficient green manure for supplying mineral N to the succeeding crop was yellow lupine.     

Sugar beet yield as affected by seed priming and weed control

Laboratory and field experiments were conducted to determine the influence of different priming techniques on the germination characteristics and competition of weeds in sugar beet in 2008–2009. Three priming times and four priming methods were used in a laboratory study, and four priming treatments and four redroot pigweed densities (0, 4, 8 and 12 plants m^?2) were used in a field study. Sugar beet seeds were treated with polyethylene glycol (PEG 8000), NaCl (1.5 N) and HCl (0.1 N) for 2, 4 and 6 h. Seed characteristics were significantly affected by HCl (0.1 N) treatment for 6 h. In this treatment, the germination percentage was 25 and 9% higher than control and NaCl (1.5 N) treatments after a similar time. An intermediate and low effect has been shown with NaCl (1.5 N) and PEG 8000 seed priming, respectively. Sugar beet root yield was reduced by 13, 54 and 89% compared with control treatment (without weed) at redroot pigweed densities of 4, 8 and 12 plants m^?2, respectively. Sugar beet seeds primed with HCl (0.1 N) for 6 h gave a higher root yield than unprimed seeeds and the other primed seeds treatments. Overall, the results showed that weed control can significantly increase sugar beet yield and the seed priming technique can be used for weed control.     

Essential oils from dalmatian sage (Salvia officinalis l.): variations among individuals, plant parts, seasons, and sites.

The factors affecting oil yield and quality of essential oils from Dalmatian sage (Salvia officinalis L.) are analyzed. Distillations of oils from individual plants and GC analyses revealed the presence of three chemotypes with different proportions of alpha- and beta-thujone (alpha/beta 10:1, 1.5:1, and 1:10). Different accessions could also be classified as having high (39-44%), medium (22-28%), or low (9%) total thujone contents. Flowering parts of S. officinalis had higher oil contents (1.6 versus 1.1%) and beta-pinene levels (27 versus 10%) than leaves and lower thujone levels (16 versus 31%). Major seasonal changes were found in the composition of oil distilled from a flowering type of Dalmatian sage, but oil yields from healthy, established plants did not vary greatly. Total thujone levels were lowest (25%) around flowering in spring and summer, so autumn or winter was the best harvest time to obtain oils with high thujone levels.     

Antithrombotic lipid minor constituents from vegetable oils. Comparison between olive oils and others

Many epidemiological studies suggest that vegetable oils and especially olive oil present a protective effect against atherosclerosis. In this study, total lipids (TL) of Greek olive oils and seed oils of four kinds, namely, soybean, corn, sunflower, and sesame oil, were separated into total polar lipids (TPL) and total neutral lipids (TNL) via a novel extraction procedure. TPL and TNL of olive oil were fractionated by HPLC for further study. Each lipid fraction from HPLC separation along with TL, TPL, and TNL lipid samples from oils were tested in vitro for their capacity to induce or to inhibit washed rabbit platelet aggregation. Comparison between olive and seed oils supports the superiority of olive oil as high levels of platelet activating factor (PAF) antagonists have been detected, mainly in TPL. In addition, the structure of the most active fraction from olive oil was elucidated, as a glycerol-glycolipid. Because it has already been reported that PAF plays a pivotal role in atherogenesis, the existence of PAF agonists and antagonists in vegetable oils may explain their protective role against atherosclerosis.     

Some furfural derivatives as nitrification inhibitors

Three series of furfural derivatives, namely N-O-furfural oxime ethers, furfural Schiff bases (furfurylidene anilines), and furfural chalcones, have been synthesized and evaluated for nitrification inhibition activity in laboratory incubation studies in typic Ustocrept soil. Furfural oxime ethers and furfural Schiff bases showed potential activity, but furfural chalcones were only mildly active. N-O-ethyl furfural oxime among the oxime ethers, and furfurylidine-4-chloroaniline among the furfural Schiff bases, performed the best. These two compounds showed more than 50% nitrification inhibition on the 45th day at 5% dose as compared to 73% inhibition by nitrapyrin. Activity of furfural oxime ethers decreased with an increase in carbon atoms in the N-O-alkyl side chain. Introduction of a chlorine atom in the phenyl ring of furfurylidene anilines increased the persistence of their activity. N-O-Ethyl furfural oxime and furfurylidine-4-chloroaniline coated urea performed at par with their application in solution form. Ethyl and N-O-isopropyl oxime, as well as chloro- and nitro- substituted Schiff bases, did not reveal any phytotoxicity (adverse effect on germination) on chickpea seeds (Cicer arietinum) even at the highest dose (40 ppm, soil basis).     

Membrane toxicity of antimicrobial compounds from essential oils

Natural antimicrobial compounds perform their action mainly against cell membranes. The aim of this work was to evaluate the interaction, meant as a mechanism of action, of essential oil antimicrobial compounds with the microbial cell envelope. The lipid profiles of Escherichia coli O157:H7, Staphylococcus aureus, Salmonella enterica serovar Typhimurium, Pseudomonas fluorescens, and Brochothrix thermosphacta cells treated with thymol, carvacrol, limonene, eugenol, and cinnamaldehyde have been analyzed by gas chromatography. In line with the fatty acids analysis, the treated cells were also observed by scanning electron microscopy (SEM) to evaluate structural alterations. The overall results showed a strong decrease of the unsaturated fatty acids (UFAs) for the treated cells; in particular, the C18:2trans and C18:3cis underwent a notable reduction contributing to the total UFA decreases, while the saturated fatty acid C17:0 raised the highest concentration in cinnamaldehyde-treated cells. SEM images showed that the used antimicrobial compounds quickly exerted their antimicrobial activities, determining structural alterations of the cell envelope.     

Comparison of eucalyptus camaldulensis Dehn. oils from Mozambique as obtained by hydrodistillation and supercritical carbon dioxide extraction

Leaf oils of E. camaldulensis Dehn. from Mozambique obtained by hydrodistillation and by supercritical carbon dioxide extraction under different conditions were compared with regard to their major components. The oil obtained by hydrodistillation showed high concentrations of 1,8-cineole (43%), alpha-pinene (5.5%), beta-pinene (3.4%), p-cymene (5.2%), terpinen-4-ol (3.1%), and globulol (4.1%). The extracts obtained by supercritical carbon dioxide extraction have lower amounts of 1,8-cineole, alpha-pinene, beta-pinene, and terpinen-4-ol, but have higher amounts of allo-aromadendrene and globulol. At the same time, distilled oil of E. radiata was extracted from an inert matrix (Celite) and the extract showed a higher content of 1,8-cineole at 80 bar and 60 degrees C than the feed, suggesting that a multiple-stage supercritical carbon dioxide extraction of the E. camaldulensis studied can produce an oil close to the market requirements set by the European pharmacopoeias.