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Main Constituents (main + constituent)

Distribution by Scientific Domains
Chemistry53%
Medical Sciences28%
Life Sciences11%
Polymers and Materials Science6%

Selected Abstracts

Mice with astrocyte-directed inactivation of connexin43 exhibit increased exploratory behaviour, impaired motor capacities, and changes in brain acetylcholine levels

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2003
Christian Frisch
Abstract Gap junctions mediate communication between many cell types in the brain. Gap junction channels are composed of membrane-spanning connexin (Cx) proteins, allowing the cell-to-cell passage of small ions and metabolites. Cx43 is the main constituent of the brain-spanning astrocytic gap junctional network, controlling activity-related changes in ion and glutamate concentrations as well as metabolic processes. In astrocytes, deletion of Cx43-coding DNA led to attenuated gap junctional coupling and impaired propagation of calcium waves, known to influence neuronal activity. Investigation of the role of Cx43 in behaviour has been impossible so far, due to postnatal lethality of its general deletion. Recently, we have shown that deletion of Cx30, which is also expressed by astrocytes, affects exploration, emotionality, and neurochemistry in the mouse. In the present study, we investigated the effects of the astrocyte-directed inactivation of Cx43 on mouse behaviour and brain neurochemistry. Deletion of Cx43 in astrocytes increased exploratory activity without influencing habituation. In the open field, but not in the elevated plus-maze, an anxiolytic-like effect was observed. Rotarod performance was initially impaired, but reached control level after further training. In the water maze, Cx43 deficient mice showed a steeper learning course, although final performance was similar between groups. Cx43 inactivation in astrocytes increased acetylcholine content in the frontal cortex of water maze-trained animals. Results are discussed in terms of altered communication between astrocytes and neurons, possible compensation processes, and differential effects of Cx30- and astrocyte-specific Cx43 deletion. [source]

Composition of the essential oils of Rhabdosciadium oligocarpum (Post ex Boiss.) Hedge et Lamond and Rhabdosciadium microcalycinum Hand.-Mazz.

FLAVOUR AND FRAGRANCE JOURNAL, Issue 4 2006
K. Hüsnü Can Ba
Abstract The volatile constituents of the oils of Rhabdosciadium oligocarpum (Post ex Boiss.) Hedge et Lamond and Rhabdosciadium microcalycinum Hand.-Mazz. (Umbelliferae) were isolated by hydrodistillation and microdistillation techniques and then analysed by GC and GC,MS. Germacrene D was found to be the main constituent in all the oils obtained. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Comparative study of the leaf oil of Juniperus macropoda growing in Garhwal regions of Uttranchal (India)

FLAVOUR AND FRAGRANCE JOURNAL, Issue 5 2005
Divya Srivastava
Abstract Leaf oils of Juniperus macropoda collected from different localities (Hindolkhal and Mussorie) of Garhwal Himalaya (Uttaranchal) exhibited much variation in their yield and composition. Oil yields in the Hindolkhal and Mussorie samples were 1.2% and 0.52% respectively. In the Hindolkhal sample, , -elemene (42.5%) was the main constituent of oil, followed by t -sabinene hydrate (8.8%) and , -cubebene (7.9%), while in the Mussorie sample the main oil constituent was , -thujone (22.6%), followed by biformene (7.7%) and sabinene (5.8%). Copyright © 2005 John Wiley & Sons, Ltd. [source]

Original article: Antifungal activities of cinnamon oil against Rhizopus nigricans, Aspergillus flavus and Penicillium expansum in vitro and in vivo fruit test

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 9 2010
Yage Xing
Summary The postharvest pathogens such as R. nigricans, A. flavas and P. expansum are the causal agents of jujube or orange fruit, therefore, in vitro and in vivo antifungal activities of cinnamon oil to inactivate these fungi were investigated. Cinnamaldehyde is the main constituent of cinnamon oil. The minimum inhibitory concentrations of cinnamon oil against Rhizopus nigricans, Aspergillus flavus and Penicillium expansum were 0.64% (v/v), 0.16% (v/v) and 0.16% (v/v), respectively. The antifungal activity of cinnamon oil against A. flavus and P. expansum was stronger than that against R. nigricans and the activity was improved with increasing its concentration. In an in vivo study, cinnamon oil with concentrations of 2.0% (v/v) and 3.0% (v/v) showed complete control the growth of fungi in wound-inoculated Lingwu Long Jujube and Sand Sugar Orange fruits. These results revealed that cinnamon oil has a good potential to be as a natural antifungal agent for fruit applications. [source]

ROLE OF SATURATED FATTY ACIDS IN LIPASE PRODUCTION , USING PSEUDOMONAS AERUGINOSA

JOURNAL OF FOOD BIOCHEMISTRY, Issue 6 2007
A.N. SARAVANAN
ABSTRACT Complex substrates always induce substantial amount of enzyme production during hydrolysis by microorganisms. In this study, ghee was taken for its saturated fatty acid content and analyzed as an inducer for the production of lipase. With ghee emulsion, the bacterium Pseudomonas aeruginosa at optimal condition produced 60 units/min/L at 72 h. With olive oil emulsion, this organism produced only 41 units/min/L as maximum at 96 h. The saturated fatty acids present in ghee make it a hard substance for hydrolysis, which is the reason for the increased enzyme production. This was evaluated by the iodine number experiment. Ghee can also reduce the production cost whereas the costlier olive oil constitutes 25,50% of the total production cost for a commercial scale. The experimental results showed that the saturated fatty acids play an important role in lipase enzyme induction by P. aeruginosa. The use of ghee is cost-effective; hence, it can be used as a potential inducer for lipase production. PRACTICAL APPLICATIONS Lipases are industrially very important enzymes. They are used in pharmaceutical, food, soap and other industries. In lipase production, olive oil is the main constituent. Comparatively, olive oil is costlier; hence, it increases the production cost of lipase. So, this study was done to replace olive oil with a much cheaper ghee using Pseudomonas aeruginosa. The ghee-containing medium gave a very good result because of the presence of complex saturated fatty acids. The ghee-containing medium produced 60 units/min/L at 72 h. The olive oil medium, which contains mainly unsaturated fatty acids, produced only 41 units/min/L as maximum at 96 h. Hence, in the commercial scale, ghee can reduce raw material cost as well as operation time cost significantly when it is used as substrate. [source]

Effects of Whey Permeate-Based Medium on the Proximate Composition of Lentinus edodes in the Submerged Culture

JOURNAL OF FOOD SCIENCE, Issue 6 2006
Xiaojun Jeffrey Wu
ABSTRACT:, Biomass production, crude water-soluble polysaccharide (WSP), ash content, mineral profile, and crude protein content were determined for Lentinus edodes mycelia grown on whey permeate (WP)-based medium with lactose content of 4.5% or defined synthetic medium, and harvested after 5, 10, 15, or 20 d of fermentation at 25 °C. Harvesting time and the type of media interact to alter the chemical content of mycelia. Mycelia grown in WP had greater (P < 0.05) WSP and ash than mycelia grown in the synthetic media. A maximum production of WSP was obtained on the 10th day (4.1 × 102± 71 mg WSP/g dried mycelia) from mycelia grown on the WP-based media. Mycelia grown on WP harvested on the 20th day had the highest value in ash content (18 ± 3%). Potassium was found to be the main constituent in the ash of mushroom mycelia, which was followed by phosphorus, sodium, calcium, and magnesium. A steady increase of ash content was only noted in mycelia grown on WP. The calcium content of WP-grown mycelia was at least 10 times higher compared to mycelia grown in the control media regardless the harvesting time. Data in this research suggested that WP was more favorable than the synthetic media in the production of WSP, which is traditionally known for their medicinal value in L. edodes. [source]

(-)-Epigallocatechin gallate induces apoptosis, via caspase activation, in osteoclasts differentiated from RAW 264.7 cells

JOURNAL OF PERIODONTAL RESEARCH, Issue 3 2007
J.-H. Yun
Background and Objective:, Alveolar bone resorption is a characteristic feature of periodontal diseases and involves removal of both the mineral and the organic constituents of the bone matrix, a process mainly carried out by multinucleated osteoclast cells. (-)-Epigallocatechin gallate, the main constituent of green tea polyphenols, has been reported to induce the apoptotic cell death of osteoclasts and to modulate caspase activation in various tumor cells. In the present study, we investigated the inhibitory effect of (-)-epigallocatechin gallate on osteoclast survival and examined if (-)-epigallocatechin gallate mediates osteoclast apoptosis via caspase activation. Material and Methods:, The effect of (-)-epigallocatechin gallate on osteoclast survival was examined by tartrate-resistant acid phosphatase (TRAP) staining in osteoclasts differentiated from RAW 264.7 cells. In addition, we evaluated the apoptosis of osteoclasts by (-)-epigallocatechin gallate using a DNA-fragmentation assay. Involvement of caspase in (-)-epigallocatechin gallate-mediated osteoclast apoptosis was evaluated by treatment with a general caspase inhibitor, Z-VAD-FMK. Moreover, the effect of (-)-epigallocatechin gallate on the activation of caspase-3 was assessed by a colorimetric activity assay and western blotting. Results:, (-)-Epigallocatechin gallate significantly inhibited, in a dose-dependent manner, the survival of osteoclasts differentiated from RAW 264.7 cells and induced the apoptosis of osteoclasts. Treatment with (-)-epigallocatechin gallate resulted in DNA fragmentation and induced the activation of caspase-3 in RAW 264.7 cell-derived osteoclasts. Additional treatment with Z-VAD-FMK suppressed these effects of (-)-epigallocatechin gallate. Conclusion:, From these findings, we could suggest that (-)-epigallocatechin gallate might prevent alveolar bone resorption by inhibiting osteoclast survival through the caspase-mediated apoptosis. [source]

Inhibitory effects of green tea polyphenol (,)-epigallocatechin gallate on the expression of matrix metalloproteinase-9 and on the formation of osteoclasts

JOURNAL OF PERIODONTAL RESEARCH, Issue 5 2004
Jeong-Ho Yun
Background:, Alveolar bone resorption is a characteristic feature of periodontal diseases and involves the removal of both the mineral and organic constituents of the bone matrix, which is caused by either multinucleated osteoclast cells or matrix metalloproteinases (MMPs). The gram-negative bacterium, Porphyromonas gingivalis has been reported to stimulate the activity and expression of several groups of MMPs, whereas (,)-epigallocatechin gallate (EGCG), the main constituent of green tea polyphenols, has been reported to have inhibitory effects on the activity and expression of MMPs. Objectives:, In the present study, we investigated the effects of the green tea polyphenol, EGCG, on the gene expression of osteoblast-derived MMP-2, -9 and -13, stimulated by P. gingivalis, and on the formation of osteoclasts. Methods:, The effect of EGCG on the gene expression of MMPs was examined by treating mouse calvarial primary osteoblastic cells with EGCG (20 µm) in the presence of sonicated P. gingivalis extracts. The transcription levels of MMP-2, -9 and -13 were assessed by reverse transcription-polymerase chain reaction (RT-PCR). The effect of EGCG on osteoclast formation was confirmed by tartrate-resistant acid phosphatase (TRAP) staining in a co-culture system of mouse bone marrow cells and calvarial primary osteoblastic cells. Results:, Treatment with the sonicated P. gingivalis extracts stimulated the expression of MMP-9 mRNA and this effect was significantly reduced by EGCG, whereas the transcription levels of MMP-2 and MMP-13 were not affected by either the sonicated P. gingivalis extracts or EGCG. In addition, EGCG significantly inhibited osteoclast formation in the co-culture system at a concentration of 20 µm. Conclusions:, These findings suggest that EGCG may prevent the alveolar bone resorption that occurs in periodontal diseases by inhibiting the expression of MMP-9 in osteoblasts and the formation of osteoclasts. [source]

Spasmolytic and antidiarrhoeal properties of the Yucatec Mayan medicinal plant Casimiroa tetrameria

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 9 2005
Michael Heinrich
The Maya of the Yucatán peninsula commonly use the leaves of Casimiroa tetrameria for treating gastrointestinal disorders, notably diarrhoea and dysentery, as well as gastrointestinal cramps. The phytochemical investigation resulted in the isolation of 13 compounds: eight polymethoxylated flavonoids (two as minor components with a main constituent), four flavonoid glycosides and one furanocoumarin. In this study we used two well-established models in order to assess the gastrointestinal effects of C. tetrameria extracts and isolated compounds: the USSING-chamber, a pharmacological model for diarrhoea, and the isolated guinea pig ileum, a model for modulatory effects on ileum contraction. Extracts and the class of polymethoxylated flavonoids showed strong inhibitory effects in both models, which provides ex-vivo evidence for the use of this botanical drug in the treatment of several gastrointestinal problems, most notably diarrhoea. The crude extract, polymethoxylated flavonoid-rich fractions and the polymethoxylated flavonoids tested showed prominent antisecretory activity. Polymethoxylated flavonoid-rich fractions also inhibited the histamine-induced contractions in the guinea pig model. The effects are not due to a single compound, but to a large number of structurally related compounds that all contribute to the effect. [source]

Randomization of Amyloid-,-Peptide(1-42) Conformation by Sulfonated and Sulfated Nanoparticles Reduces Aggregation and Cytotoxicity

MACROMOLECULAR BIOSCIENCE, Issue 10 2010
Ana M. Saraiva
Abstract The amyloid-, peptide (A,) plays a central role in the mechanism of Alzheimer's disease, being the main constituent of the plaque deposits found in AD brains. A, amyloid formation and deposition are due to a conformational switching to a ,-enriched secondary structure. Our strategy to inhibit A, aggregation involves the re-conversion of A, conformation by adsorption to nanoparticles. NPs were synthesized by sulfonation and sulfation of polystyrene, leading to microgels and latexes. Both polymeric nanostructures affect the conformation of A, inducing an unordered state. Oligomerization was delayed and cytotoxicity reduced. The proper balance between hydrophilic moieties and hydrophobic chains seems to be an essential feature of effective NPs. [source]

Thymoquinone supplementation attenuates hypertension and renal damage in nitric oxide deficient hypertensive rats

PHYTOTHERAPY RESEARCH, Issue 5 2007
Mahmoud M. Khattab
Abstract The present study was undertaken to evaluate the protective effect of thymoquinone (TQ), the main constituent of the volatile oil from Nigellasativa seeds, in rats after chronic inhibition of nitric oxide synthesis with N, -nitro- l -arginine methyl esters (l -NAME). Rats were divided randomly into different treatment groups: control, l -NAME, TQ and l -NAME + TQ. Hypertension was induced by 4 weeks administration of l -NAME (50 mg/kg/day p.o.). TQ was administered alone or in combination with l -NAME and continued for 4 weeks. The animals were killed, and the serum and kidney tissues were isolated for the determination of creatinine and glutathione (GSH), respectively. Rats receiving l -NAME showed a progressive increase in systolic blood pressure compared with control rats. Concomitant treatment with TQ (0.5 and 1 mg/kg/day p.o.) reduced the increase in systolic blood pressure induced by l -NAME in a dose dependent manner. Kidney injury was demonstrated by a significant increase in serum creatinine and a decrease in GSH in kidney tissue from l -NAME treated rats. Treatment of rats with TQ decreased the elevated creatinine and increased GSH to normal levels. TQ inhibited the in vitro production of superoxide radical in enzymatic and non-enzymatic systems. In conclusion, TQ is effective in protecting rats against l -NAME-induced hypertension and renal damage possibly via antioxidant activity. Copyright © 2007 John Wiley & Sons, Ltd. [source]

The anxiolytic effect of Sho-ju-sen, a Japanese herbal medicine, assessed by an elevated ­plus-maze test in mice

PHYTOTHERAPY RESEARCH, Issue 2 2001
Hisashi Kuribara
Abstract Sho-ju-sen (SK), a Japanese herbal medicine with a nourishing tonic action, is composed of a water extract of Kumazasa leaves (Sasa kurinensis Makino et Sibata) (SS), and ethanol extracts of Japanese red pine needles (Pinus densiflora Sieb. et Zucc) (PN) and Ginseng roots (Panax ginseng C. A. Meyer) (PX) in the ratio 8:1:1. In this study, an elevated plus-maze test in mice was carried out to assess whether SK had an anxiolytic effect. No significant change was observed in either the plus-maze or activity test following a single administration of SK (10 and 20,mL/kg p.o.). However, mice allowed a free intake of SK (10% solution) for 5 days and longer showed a significant prolongation of the time spent in the open arms (an anxiolytic effect), as long as that caused by the benzodiazepine anxiolytic diazepam (1,mg/kg p.o.). SK (1%, 3% and 30% solutions for 7 days) tended to develop the anxiolytic effect. Of the constituents of SK, SS (8% solution), but not PN (1% solution) or PX (1% solution), resulted in the anxiolytic effect. Except for a slight acceleration in the motor activity by PN (1% solution), no significant change in the motor activity was produced by any treatment with SK, SS or PX. The combined treatment of SK (10% solution) or SS (8% solution) with 1,mg/kg diazepam enhanced the anxiolytic effect. Flumazenil (0.1,mg/kg s.c.), a benzodiazepine receptor antagonist, alone did not change the time spent in the open arms. However, it completely reversed the anxiolytic effect of SK, SS and diazepam. The present results suggest that: (1) long-term treatment with SK develops an anxiolytic effect, (2) SS is the main constituent for the anxiolytic effect of SK, and (3) benzodiazepine receptors are involved in the anxiolytic effect of SK and SS. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Involvement of apoptosis and cholinergic dysfunction in Alzheimer's disease

PSYCHOGERIATRICS, Issue 2006
Shinji TAGAMI
Abstract As Alzheimer's disease (AD) progresses, brain atrophy becomes conspicuous, and histologically there is neuronal loss, primarily with a deficit of cholinergic neurons observed. Hitherto, the view has been that cell death, apoptosis, plays a role in this neuronal loss. Apoptosis is characterized by the morphological changes of nuclear fragmentation, chromatin condensation and cell shrinkage, with activation of caspases, members of the cysteine protease family, resulting in considerable substrate cleavage. TUNEL positive neurons have in fact been detected in AD brain, indicating increased caspase activity and resulting substrate cleavage. In AD brain, amyloid beta peptides (A,), the main constituent of senile plaque, are a specific pathological hallmark observed in extracellular spaces. In contrast, the main constituent of intracellularly observed neurofibrillary tangles (NFT) is hyperphosphorylated tau, which is observed in various neurodegenerative disorders other than AD. The viewpoint of many studies is that the A, and NFT that cause these neuropathological changes probably participate in neuronal death. However, up until now it has been thought that there was no hypothesis offering a comprehensive explanation of how the accumulation of extracellular A, and intracellular NFT leads to neuronal death. This report first covers the mechanism of apoptosis as clarified by molecular biological methods, and provides an explanation of how apoptosis could be involved in AD pathology. The subject of autophagic cell death, a type of cell death morphology that has recently been the focus of attention, is also addressed. [source]

Elucidation of the molecular structure of lipid A isolated from both a rough mutant and a wild strain of Aeromonas salmonicida lipopolysaccharides using electrospray ionization quadrupole time-of-flight tandem mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 12 2005
Anas El-Aneed
The chemical structure of lipid A, isolated by mild acid hydrolysis from a rough mutant and a wild strain of Aeromonas salmonicida lipopolysaccharide, was investigated using electrospray ionization quadrupole time-of-flight (QqToF) hybrid tandem mass spectrometry and showed a great degree of microheterogeneity. The chemical structure of the main constituent of this heterogeneous mixture was identified as a , -D-(1,,,6) linked D-glucosamine disaccharide substituted by two phosphate groups, one being bound to the non-reducing end at position O-4, and the other to the position O-1 of the reducing end of the D-glucosamine disaccharide. The location of the fatty acids linked to the disaccharide backbone was established by identifying diagnostic ions in the conventional QqToF-MS scan. Low-energy collision tandem mass spectrometry analysis of the selected precursor diagnostic ions confirmed, unambiguously, their proposed molecular structures. We have established that myristyloxylauric (C14:0(3- O(12:0))) acid residues were both N-2, and O-3, linked to the non-reducing end of the D-GlcN residue, and that two 3-hydroxymyristic (C14:0(3-OH)) acid chains acylated the remaining positions of the reducing end. The MS and MS/MS data obtained allowed us to determine the complex molecular structure of lipid A. The QqToF-MS/MS instrument has shown excellent superiority over a conventional quadrupole-hexapole-quadrupole tandem instrument which failed to fragment the selected precursor ion. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Green tea: Health benefits as cancer preventive for humans

THE CHEMICAL RECORD, Issue 3 2005
Hirota Fujiki
Abstract Green tea is an acknowledged cancer preventive in Japan. The aim of this review article is to develop the concept of cancer prevention with green tea beverage for humans, which has largely been our exclusive research territory. This paper briefly reviews several topics, beginning with the introduction of our initial work on penta- O -galloyl-,-D-glucose and (,)-epigallocatechin gallate (EGCG), the main constituent of green tea extract. The mechanisms of EGCG action, particularly the reduction of TNF-, are discussed, and we show how use of 3H-EGCG revealed a wide range of target organs for cancer prevention. The results of an epidemiological study in Saitama Prefecture allowed us to determine the cancer preventive amount of green tea,10 Japanese-size cups per day, about 2.5,g green tea extract,which made it possible for us to introduce the two-stage strategy of cancer prevention with green tea. The first stage is the delay of cancer onset for the general population. The second stage is the prevention of recurrence of cancer for patients following cancer treatment. Combination cancer prevention with green tea and cancer preventive drugs is proving especially beneficial for Japanese, who drink green tea every day. And finally, the stimulating comments of Prof. Jim Watson have encouraged green tea scientists. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 5: 119,132; 2005: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20039 [source]

Inhibitory Effects of Silibinin on Cytochrome P-450 Enzymes in Human Liver Microsomes

BASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 6 2000
Svane Beckmann-Knopp
Silibinin, the main constituent of silymarin, a flavonoid drug from silybum marianum used in liver disease, was tested for inhibition of human cytochrome P-450 enzymes. Metabolic activities were determined in liver microsomes from two donors using selective substrates. With each substrate, incubations were carried out with and without silibinin (concentrations 3.7,300 ,M) at 37° in 0.1 M KH2PO4 buffer containing up to 3% DMSO. Metabolite concentrations were determined by HPLC or direct spectroscopy. First, silibinin IC50 values were determined for each substrate at respective KM concentrations. Silibinin had little effect (IC50>200 ,M) on the metabolism of erythromycin (CYP3A4), chlorzoxazone (CYP2E1), S(+)-mephenytoin (CYP2C19), caffeine (CYP1A2) or coumarin (CYP2A6). A moderate effect was observed for high affinity dextromethorphan metabolism (CYP2D6) in one of the microsomes samples tested only (IC50=173 ,M). Clear inhibition was found for denitronifedipine oxidation (CYP3A4; IC50=29 ,M and 46 ,M) and S(,)-warfarin 7-hydroxylation (CYP2C9; IC50=43 ,M and 45 ,M). When additional substrate concentrations were tested to assess enzyme kinetics, silibinin was a potent competitive inhibitor of dextromethorphan metabolism at the low affinity site, which is not CYP2D6 (Ki,c=2.3 ,M and 2.4 ,M). Inhibition was competitive for S(,)-warfarin 7-hydroxylation (Ki,c=18 ,M and 19 ,M) and mainly non-competitive for denitronifedipine oxidation (Ki,n=9 ,M and 12 ,M). With therapeutic silibinin peak plasma concentrations of 0.6 ,M and biliary concentrations up to 200 ,M, metabolic interactions with xenobiotics metabolised by CYP3A4 or CYP2C9 cannot be excluded. [source]

Biological Conversion of Anglesite (PbSO4) and Lead Waste from Spent Car Batteries to Galena (PbS)

BIOTECHNOLOGY PROGRESS, Issue 4 2002
Jan Weijma
Lead paste, a solid mixture containing PbSO4, PbO2, PbO/Pb(OH)2precipitate, and elemental Pb, is one of the main waste fractions from spent car batteries. Biological sulfidation represents a new process for recovery of lead from this waste. In this process the lead salts in lead paste are converted to galena (PbS) by sulfate-reducing bacteria. This paper investigates a continuous process for sulfidation of anglesite (PbSO4), the main constituent of lead paste, and lead paste, consisting of a laboratory-scale gas-lift bioreactor to which a slurry of anglesite or lead paste was supplied. Sulfate or elemental sulfur was added as an additional sulfur source. Hydrogen gas served as an electron donor for the biological reduction of sulfate and elemental sulfur to sulfide by sulfate- and sulfur-reducing bacteria. Anglesite was almost completely converted to galena at a loading rate of 19 kg of PbSO4m,3day,1, producing a sludge of which the crystalline lead phases consisted of >98% PbS (galena) and 1,2% elemental Pb. With lead paste, stable sulfidation rates of up to 17 kg of lead paste m,3day,1were demonstrated, producing a sludge of which the crystalline lead phases consisted of an estimated >96% PbS, 1,2% elemental Pb, and 1,2% PbO2. [source]

The chemical composition of essential oils and lipophilic extracts of Silphium integrifolium Michx. and S. trifoliatum L. leaves

FLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2008
Rados, aw Kowalski
Abstract The research presented in this paper revealed that secretory ducts in leaf stalks and main nerves of leaf blades of S. integrifolium and S. trifoliatum were of schizogenic origin and were present in varied number around vascular bundles. GC,FID and GC,MS analyses of essential oils and lipophilic extracts made from leaves collected from tested Silphium species in 1999,2001 and 2007 indicated that sesquiterpene compounds were the main constituents: germacrene D, ,- caryophyllene, caryophyllene oxide and silphiperfol-6-en-5-one. Only the oil and extracts from S. integrifolium contained significant amounts of allo -aromadendr-9-ene (8.5 ± 4.2% in oil achieved in 1999,2001, as well as 3.7 ± 0.1% and 5.7 ± 0.3 µg/ml, respectively in essential oil and extract (1:10) from 2007). Besides volatile compounds, sterols such as , -sitosterol and stigmasterol as well as triterpene alcohols (,- amyrine and , -amyrine), higher alkanes, free fatty acids and their derivatives along with vitamin E were present in tested lipophilic extracts. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Chemical composition and antibacterial activity of the essential oil of Michelia foveolata Merryll ex Dandy from Vietnam

FLAVOUR AND FRAGRANCE JOURNAL, Issue 4 2007
Dominique Lesueur
Abstract The chemical composition of the volatile oil extracted from aerial parts (twigs, leaves and flowers) of Michelia foveolata growing wild in Vietnam was investigated by combination of column chromatography, GC (retention indices), GC,MS and 13C-NMR spectroscopy. Fifty-eight components were identified, with sabinene (32.4%) and terpinen-4-ol (13.7%) as the main constituents. The essential oil was tested against 11 bacteria using the agar disc diffusion method, and exhibited a significant antibacterial activity against Salmonella enterica, Staphylococcus epidermidis, Staphylococcus aureus and Bacillus cereus (MICs = 2,4 µl/ml). Copyright © 2007 John Wiley & Sons, Ltd. [source]

Impact of estragole and other odorants on the flavour of anise and tarragon

FLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2007
Annette Zeller
Abstract Since estragole has been described as potent carcinogen and did not show any flavour impact on the odour of fennel, the flavour of anise and tarragon was examined by combinations of instrumental and sensory analyses. In anise fruits, trans- anethole, 2-isopropyl-3-methoxypyrazine, and anisaldehyde showed high flavour dilution (FD) factors, followed by those of eugenol, cis- anethole, estragole and linalool. Quantitation of the odorants showing higher FD factors in anise tea, and calculation of odour activity values (OAVs) by dividing the concentrations of the respective compound by its recognition threshold in water revealed the highest OAV for trans- anethole, followed by those of anisaldehyde and estragole. Still, an aroma impact of estragole next to trans- anethole could be neglected, due to former sensory studies of aqueous models of fennel tea. For tarragon, AEDA revealed the highest FD factors for eugenol, 7-methoxycoumarin, , -ionone, 2-isopropyl-3-methoxypyrazine, estragole and linalool. Of these, estragole and 7-methoxycoumarine were most abundant in tarragon leaves, showing contents of 2900 and 220 mg/kg, respectively. To calculate OAVs, the contents of potent odorants were divided by their odour threshold in starch or cellulose, as these were the main constituents of the leaves. In this way, , -ionone and eugenol showed the highest OAVs of 5862 and 2653, repectively, followed by estragole (OAV = 460), cis- 1,5-octadiene-3-one (OAV = 140), vanilline (OAV = 139) and 2-isopropyl-3-methoxypyrazine (OAV = 130). Therefore, it was concluded that , -ionone and eugenol made the greatest contribution to the overall flavour of tarragon, whereas estragole and the other odorants were of minor importance. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Inhibition of acetylcholinesterase activity by tea tree oil and constituent terpenoids

FLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2006
Mitsuo Miyazawa
Abstract In vitro inhibition of bovine erythrocyte acetylcholinesterase (AChE) activity by tea tree oil was investigated. The main constituents in the tea tree oil batch used for the analysis of AChE inhibition were terpinen-4-ol (35.6%), , -terpinene (19.5%), , -terpinene (8.3%), p -cymene (7.2%) and 1,8-cineole (4.4%). AChE was measured by a colorimetric method. IC50 values were obtained for tea tree oil and , -pinene and were 51.2 µg/ml and 57.1 µg/ml, respectively. Tea tree oil was found to contain mixed-type inhibitors; a mixture of main constituents and main constituents showed competitive inhibition. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Inhibition of acetylcholinesterase activity by tea tree oil and constituent terpenoids

FLAVOUR AND FRAGRANCE JOURNAL, Issue 6 2005
Mitsuo Miyazawa
Abstract In vitro inhibition of bovine erythrocyte acetylcholinesterase activity by tea tree oil was investigated. The main constituents in the tea tree oil batch used for analysis of acetylcholinesterase inhibition were terpinen-4-ol (35.6%), , -terpinene (19.5%), , -terpinene (8.3%), p -cymene (7.2%) and 1,8-cineole (4.4%). AChE was measured by a colorimetric method. IC50 values were obtained for tea tree oil and , -pinene and were 51.2 and 57.1 µg[sol ]ml, respectively. Tea tree oil was found to comprise of mixed type inhibitors as the main constituents. The main constituents were competitive inhibitors. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Analysis of the essential oil of algerian Hypericum perfoliatum (L)

FLAVOUR AND FRAGRANCE JOURNAL, Issue 6 2005
O. Touafek
Abstract The hydrodistilled essential oil of Hypericum perfoliatum (Clusiaceae), grown at Jijel (north-eastern Algeria), was analysed by GC,MS; 35 components, representing 96% of the oil, have been identified, with thymol (22.10%), T-cadinol (18.5%) and 4,5-dimethyl-2-ethylphenol (13%) as the main constituents. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Chemical constituents of the essential oil of Asarum forbesii Maxim (Aristolochiaceae)

FLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2005
Feng Zhang
Abstract The essential oils from the leaves and roots of Asarum forbesii Maxim (Aristolochiaceae) were obtained by hydrodistillation and analysed by GC and GC,MS; 20 and 17 constituents were identi,ed from the leaf and root oils, respectively. Methylisoeugenol (33.3%) and , -asarone (19.2%) were the main constituents in the leaf oil, while , -asarone (58.8%) and methyleugenol (10.3%) were the major constituents in the root oil. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Neutral components from hexane extracts of Croton sellowii

FLAVOUR AND FRAGRANCE JOURNAL, Issue 1 2004
Sebastião F. Palmeira Jr
Abstract Qualitative analyses by GC,FID and GC,MS of the neutral fractions from hexane extract of the leaves, stems and roots of Croton sellowii were carried out. Sesquiterpenoids, n -alkanes, aliphatic esters and aliphatic alcohols and alkyl benzene derivatives were identi,ed. Caryophyllene oxide (46.8%) and trans -caryophyllene (40.8%) were most abundant in the leaves, while caryophyllene oxide (26.5%) and cubenol (16.7%) were the main constituents in the stems. In the roots, besides mesitylene (15.2%), the sesquiterpenes , -(7.6%), , -(6.9%) and , -eudesmol (5.5%) were the most abundant components. All identi,ed constituents are described for the ,rst time in this species. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Chemical composition of the essential oil of Pistacia lentiscus L. from Morocco,a seasonal variation

FLAVOUR AND FRAGRANCE JOURNAL, Issue 6 2003
S. Zrira
Abstract Air-dried aerial parts of Pistacia lentiscus L. collected from different regions of Morocco (Mehdia, Oulmes and Chaouen) were water-distilled to produce oil in 0.2% yields. The chemical composition of P. lentiscus oils changes from a region to another. The variations in chemical composition are important between plant populations. A total of 45 constituents were identi,ed. The major oil components of P. lentiscus from Oulmes were , -pinene (16.5,38.5%), , -myrcene (10.2,11.5%) and limonene (6.8,9.8%), while terpinen-4-ol (32.7,43.8%), , -pinene (7.1,13.5%) and bornyl acetate (6.8,10.3%) were the main constituents of Chaouen oil. For P. lentiscus from Mehdia, terpinen-4-ol (14.5,19.3%), caryophyllene oxide (6.5,10.3%) and limonene (6.7,8.1%) were the major components. The effect of harvesting time on the oil production and chemical composition was also examined at different vegetative stages (December,June). For the three locations, the best oil content was obtained during the ,owering period March,June. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Chemical composition variability of the essential oil of Conyza canadensis Cronq.

FLAVOUR AND FRAGRANCE JOURNAL, Issue 5 2003
Anna Lis
Abstract The essential oils from different botanical parts (herb, leaves, ,owers, stems, roots) of Conyza canadensis Cronq. were analysed at various ontogenesis phases. R -(+)-limonene and trans - , -bergamotene were the main constituents of the herb, leaf and ,ower oil at all phases of vegetation. The early ,owering phases are the best time for harvesting C. canadensis herb, because the oil yield is the highest (0.7,0.8%) and its chemical composition is constant (limonene 80,81%, trans - , -bergamotene 6,8%). Limonene was the dominating compound of the oils of European origin (French, Italian, Spanish, Belgian, Bulgarian and Lithuanian). Copyright © 2003 John Wiley & Sons, Ltd. [source]

The essential oil of Achillea falcata L.

FLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2003
Mine Kürkçüo
Abstract Water-distilled oils of Achillea falcata L. collected from two different localities in Turkey were analysed by GC,MS. Fifty-two and 60 components were identi,ed, representing 95% and 90%, respectively, of the total oil. 1,8-Cineole (14,24%), camphor (4,24%), , -pinene (2,12%) were characterized as the main constituents. The enantiomeric distribution of 1S(,) camphor was measured as 93.3% and 99.6% in the two oils, respectively. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Chemical composition of essential oils of Senecio nutans Sch.-Bip. (Asteraceae)

FLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2003
Vincenzo De Feo
Abstract The essential oils from the aerial parts of Senecio nutans Sch.-Bip., collected in two different localities at 3500 and 4800 m above sea level in the Department of Arequipa, Perù, were obtained by hydrodistillation in 0.16% and 0.18% yields, respectively, related to the fresh weight. The oils were characterized by GC and GC,MS analyses. In the oil from plants at the lower altitude, 21 of 25 components were identi,ed; the oil from the higher altitude site showed the presence of 46 components, 41 of which were identi,ed. Monoterpene hydrocarbons predominated in both oils, with sabinene and , -terpinene as the main constituents. Copyright © 2003 John Wiley & Sons, Ltd. [source]

N-Palmitoyl-4-Hydroxy- L -Proline Palmityl Ester: A Pseudoceramide that Provides Efficient Skin Barrier Repair and Protection

INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2006
G. Vielhaber
Ceramides are the main constituents of the epidermal permeability barrier, and it has been demonstrated that the application of ceramide enriched creams promotes epidermal barrier repair. However, nature-identical ceramides are extremely expensive and difficult to formulate. We therefore developed a new pseudoceramide, N-palmitoyl-4-hydroxy- l -proline palmityl ester (BIO391). Due to its low melting point of £60°C the pseudoceramide BIO391 can easily be incorporated into cosmetic formulations. In addition, it is very safe for use in cosmetics. The efficacy of the pseudoceramide BIO391 was investigated in vivo in a model for detergent-induced barrier disruption. Trans-epidermal water loss, redness, and skin hydration were recorded before and after barrier disruption as well as during the subsequent 9-day treatment with the test products. Barrier repair of skin treated with the pseudoceramide BIO391 was accomplished earlier than that of untreated and vehicle treated skin. Optimum barrier repair was achieved with 1.0% pseudoceramide BIO391 and optimum erythema reduction with 0.5% pseudoceramide BIO391. The optimum dosage could be reduced to 0.1% pseudo-ceramide by synergistic combination with 0.1% (-)-a-bisabolol. In addition, the pseudoceramide BIO391 proved to be as effective as nature-identical ceramides 2 and 3. In summary, N-palmitoyl-4-hydroxy- l -proline palmityl ester is a highly efficient barrier repair agent with efficacy equivalent to that of nature-identical ceramides, and it has excellent formulation properties. [source]