Essential oil composition of juvenile leaves from coppiced Eucalyptus nitens

The essential oil of Eucalyptus nitens juvenile foliage harvested from coppiced trees contained α-pinene, limonene, 1,8-cineol, cis-ocimene and α-terpineol as principal components. Minor constituents were monoterpene alcohols, ketones, and aldehydes and 3-methylbutanal. Esters not previously identified in E. nitens leaf oil were ethyl 3-methylbutanoate, 3-methylbutyl-3-methylbutanoate, 3-methylbutyl hexanoate and hexyl 3-methylbutanoate.     

Volatile compounds of the green alga, Capsosiphon fulvescens

Essential oils extracted by static vacuum simultaneous distillation–extraction (V-SDE) and conventional SDE from a green alga, Capsosiphon fulvescens, were analyzed by gas chromatography (GC) and GC-mass spectrometry. The essential oil extracted with V-SDE and SDE has totals of 151 and 140 compounds, respectively. A combined total of 208 compounds were identified and 81 volatiles were common in both extracts. These included 8 acids, 28 alcohols, 34 aldehydes, 11 esters, 25 ketones, 19 aliphatic hydrocarbons, 43 branched hydrocarbons, 6 unsaturated hydrocarbons, 19 cyclic hydrocarbons, and 15 miscellaneous. The major volatile compounds of the oil extracted with V-SDE were (E)-β-ionone, octane, (E,E)-2,4-heptadienal, hexadecanoic acid, and β-cyclocitral, while those extracted with SDE were hexadecanoic acid, (Z,Z)-1,5-octadien-3-ol, tetradecanoic acid, (E,E)-2,4-heptadienal, and benzaldehyde. The characteristics of the flavor of the green alga might be contributed by the presence of a large number of aldehydes and ketones. Many of the compounds extracted with SDE might originate from thermal degradation and/or thermal interactions among the constituents in the alga during steam distillation.     

Feeding heat-oxidized oil to dairy cows affects milk fat nutritional quality

Heating oil and oilseeds results in oxidation products that affect ruminal biohydrogenation of polyunsaturated fatty acids, altering milk fatty acids profile, and could be transferred to milk. An experiment was conducted to investigate the effects of oil heating on rumen and milk fatty acids profile and the transfer of oxidation products to milk. Sunflower oil was heated at 150°C for 15 h and given to lactating dairy cows in a 2×2 arrangement: two groups of two cows, equipped with a ruminal cannula and receiving two diets (containing either heated or unheated oil) during two experimental periods. Oil heating generated hydroperoxides and/or hydroxyacids and aldehydes, in particular trans-2,trans-4-decadienal. In milk, heated oil only significantly decreased trans-11-C18:1 and cis-9,trans-11-CLA percentage compared to non-heated oil, and slightly increased cis-9,cis-12-C18:2 percentage, which was probably linked to an inhibition of the ruminal Δ12 isomerase by oxidative products in the rumen. However, feeding highly oxidized oil did not result in the appearance of hydroperoxides or hydroxyacids in milk and did not increase milk aldehydes content.     

Antibacterial Activity and Kinetics of Litsea cubeba Oil on Escherichia coli

Litsea cubeba oil is extracted from the fresh fruits of Litsea cubeba by distillation. In this study, its chemical constituents, antibacterial activity, kinetics and effects against Escherichia coli were studied. Its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were both 0.125% (v/v) by toxic food method. Moreover, the antibacterial kinetic curves indicated 0.0625% (v/v) of litsea cubeba oil was able to prolong the growth lag phase of E. coli cells to approximate 12 hours while 0.125% (v/v) of litsea cubeba oil was able to kill the cells completely. Furthermore, transmission electron microscope (TEM) observation showed most E. coli cells treated with 0.125% (v/v) of litsea cubeba oil were killed or destroyed severely within 2 hours. The litsea cubeba oil might penetrate and destroy the outer and inner membrane of E. coli cells. Thus many holes and gaps were observed on the damaged cells, which led to their death eventually. The antibacterial effects of litsea cubeba oil mainly attributed to the presence of aldehydes, which accounted for approximately 70% in its whole components analyzed by GC/MS. Based on the antimicrobial properties, litsea cubeba oil would have a broad application in the antimicrobial industry.     

Volatile components of Artemisia monosperma and Artemisia judaica growing in the Egyptian deserts

Volatile components of Artemisia monosperma and of Artemisia judaica obtained by steam distillation of the fresh plants were analysed by capillary gas chromatography/mass spectrometry. Volatile oil of A. monosperma was found to be made up primarily of highly unsaturated hydrocarbons and aromatic acetylenic compounds with 3-methyl-3-phenyl-1,4-pentadiyne being the major component. Volatile oil of A. judaica, on the other hand, was found to be a mixture of esters, ketones and aldehydes in which pipertone is the major component.     

Sulphides and furanones from steam volatile oils of Allium fistulosum and Allium chinense

The constituents of the steam volatile oils from two kinds of Allium fistulosum, A. fistulosum var. caespitosum and A. chinense, have been investigated by GC and spectral techniques (IR, UV, GC/MS, ¹H NMR and ¹³C NMR). The compounds identified from the neutral fraction of each volatile oil included sulphides, thiolanes, alcohols, aldehydes, ketones, furanones and others. Among the sulphur compounds, dipropyl disulphide comprised ca 28% of A. fistulosum oil, ca 23% of A. fistulosum var. caespitosum oil and ca 30% of A. chinense oil. A. fistulosum oil was characterized by a large quantity of tridecan-2-one (ca 52%) and 2,3-dihydro-2-octyl-5-methylfuran-3-one (ca 16%). Also, a large amount of 2,3-dihydro-2-hexyl-5-methylfuran-3-one (ca 20%) was isolated from A. chinense oil.     

Effects of aldehydes on CD36 expression

Introduction: During the oil frying process lipid peroxidation compounds are formed. These products can modulate gene expression and alter cellular behaviour. The cellular uptake of oxidized LDL, a key step in the development of atherosclerosis, is mediated by the CD36 scavenger receptor, whose expression is down-regulated by α-tocopherol.

Objective: To determine the effects of water-soluble aldehydes, obtained from thermally oxidized sunflower oil on the expression of CD36 scavenger receptor in human monocytes (THP-1 cells). We also wanted to study the effects of α-tocopherol on CD36 expression in the presence of water-soluble aldehydes.

Materials and Methods: Sunflower oil was heated in a frying pan, at 180–200°C for 40?min, water-soluble aldehydes were isolated, and the content of thiobarbituric acid reacting substances (TBARS) was determined. THP-1 monocytes were cultured in RPMI medium during 24?h and incubated with increasing concentrations of the water-soluble aldehydes (ranging from 0.05 to 1?μM) and with or without 50?μM of α-tocopherol. In parallel, THP-1 cells were cultured with the same volume of an extract obtained from non-oxidized oil or distilled water. The CD36 expression at the cell surface was studied with fluorescence-activated cell sorting (FACS).

Results: Monocytes incubated in a medium containing water-soluble aldehydes, showed a dose dependent increase in the expression of the CD36 protein on the cell surface, compared to with the control groups. When the cells were treated simultaneously with 50?μM of α-tocopherol a significant reduction in the expression of the CD36 protein was observed.

Conclusion: Water-soluble aldehydes, extracted from thermally oxidized culinary oil, increase the expression of CD36. This effect is partially decreased by the presence of α-tocopherol.     

火棘花挥发油化学成分的GC-MS分析及抗氧化活性研究

采用水蒸气蒸馏法提取火棘花挥发油,利用气相色谱—质谱联用技术(GC-MS)分析其化学成分。使用维生素C和BHT为阳性对照,以DPPH自由基、亚硝酸钠清除作用为指标评价挥发油的抗氧化活性。从挥发油中鉴定了77个化合物,占挥发油总量的83.77%,含有多种生物活性成分,以萜类及其含氧衍生物(50.31%)、烷烃(18.52%)、醛(5.54%)为主;挥发油对DPPH自由基、亚硝酸钠有明显的清除作用,清除率为50%时,其体积分别为43.51、79.48μL,样品量与清除率间呈量效关系;挥发油对DPPH自由基的清除效果略低于1 mg·mL-1维生素C,对亚硝酸钠的清除效果优于1 mg·mL-1的BHT。     

Properties of oil and char derived from slow pyrolysis of Tetraselmis chui

Pyrolysis of biomass is a means to industrially manufacture renewable oil and gas, in addition to biochar for soil amendment and long-term carbon fixation. In this work, oil and char derived from the slow pyrolysis of the unicellular marine diatom Tetraselmis chui are analysed using a variety of techniques. The pyrolytic oil fraction exhibits a wide variety of fatty acids, alkanes, alkenes, amides, aldehydes, terpenes, pyrrolidinines, phytol and phenols, with a high heating value (HHV) of 28 MJ/kg. The biochar produced has a HHV of 14.5 MJ/kg and reveals a number of properties that are potentially valuable from an agronomic point of view, including high cation exchange capacity (CEC), large concentration of N, and a low C:N ratio. The quantity of C in T. chui biochar that can be expected to stabilise in soil amounts to approximately 9%/wt of the original feedstock, leading to a potential net reduction in atmospheric CO₂.     

Effect of the antifungal activity of oxygenated aromatic essential oil compounds on the white-rot Trametes versicolor and the brown-rot Coniophora puteana

Essential oils and their constituents have a long history of applications as antimicrobial agents, but their use as wood preservatives has not yet been reported. In this study, 22 essential oil phenols, phenol ethers, and aromatic aldehydes have been tested for their antifungal activity against the wood-decaying fungi Trametes versicolor and Coniophora puteana. Minimal inhibitory concentrations of the selected compounds added to potato dextrose agar (PDA) in defined concentrations were determined by a screening test with the agar dilution method. A significant difference in the tolerance of the tested fungi towards the selected compounds was discovered and attributed to the differences in their metabolic characteristics. The influence of the chemical structure of the tested essential oil compounds on their antifungal activity is also discussed.     

Volatile constituents of male and female boll weevils and their frass

The volatile constituents of male and female boll weevils, Anthonomus grandis, and their frass were analysed by GLC-MS. The 4 previously identified components of the male pheromone were present only in the male volatile oil (3·9%) and in the male frass volatile oil (38·9%). The compounds found in one or both sexes and their frass include 26 carbonyls, 23 hydrocarbons, 12 alcohols, 6 phenols, 4 esters, 3 furans, 1 ether, and 1 lactone. Also found were 2 compounds containing nitrogen, 1 halogen, and 1 sulphur. There were 33 terpenes and 24 aromatic compounds. 3,7-Dimethyl-1-octanol comprised 15·6 per cent of the male frass oil. Carvone was found only in females (5·4%) and in female frass (6·8%). A series of monoterpene aldehydes (M⁺ 152) were found only in the female frass oil. A pheromone rôle for these components was suggested.     

Effects of aldehydes on CD36 expression

INTRODUCTION: During the oil frying process lipid peroxidation compounds are formed. These products can modulate gene expression and alter cellular behaviour. The cellular uptake of oxidized LDL, a key step in the development of atherosclerosis, is mediated by the CD36 scavenger receptor, whose expression is down-regulated by alpha-tocopherol.OBJECTIVE: To determine the effects of water-soluble aldehydes, obtained from thermally oxidized sunflower oil on the expression of CD36 scavenger receptor in human monocytes (THP-1 cells). We also wanted to study the effects of alpha-tocopherol on CD36 expression in the presence of water-soluble aldehydes.MATERIALS AND METHODS: Sunflower oil was heated in a frying pan, at 180--200 degrees C for 40 min, water-soluble aldehydes were isolated, and the content of thiobarbituric acid reacting substances (TBARS) was determined. THP-1 monocytes were cultured in RPMI medium during 24 h and incubated with increasing concentrations of the water-soluble aldehydes (ranging from 0.05 to 1 microM) and with or without 50 microM of alpha-tocopherol. In parallel, THP-1 cells were cultured with the same volume of an extract obtained from non-oxidized oil or distilled water. The CD36 expression at the cell surface was studied with fluorescence-activated cell sorting (FACS).RESULTS: Monocytes incubated in a medium containing water-soluble aldehydes, showed a dose dependent increase in the expression of the CD36 protein on the cell surface, compared to with the control groups. When the cells were treated simultaneously with 50 microM of alpha-tocopherol a significant reduction in the expression of the CD36 protein was observed.CONCLUSION: Water-soluble aldehydes, extracted from thermally oxidized culinary oil, increase the expression of CD36. This effect is partially decreased by the presence of alpha-tocopherol.     

Oxidation of N-Nitrosoalkylamines by Human Cytochrome P450 2A6: SEQUENTIAL OXIDATION TO ALDEHYDES AND CARBOXYLIC ACIDS AND ANALYSIS OF REACTION STEPS*

Cytochrome P450 (P450) 2A6 activates nitrosamines, including N,N-dimethylnitrosamine (DMN) and N,N-diethylnitrosamine (DEN), to alkyl diazohydroxides (which are DNA-alkylating agents) and also aldehydes (HCHO from DMN and CH₃CHO from DEN). The N-dealkylation of DMN had a high intrinsic kinetic deuterium isotope effect (^Dk_app ∼ 10), which was highly expressed in a variety of competitive and non-competitive experiments. The ^Dk_app for DEN was ∼3 and not expressed in non-competitive experiments. DMN and DEN were also oxidized to HCO₂H and CH₃CO₂H, respectively. In neither case was a lag observed, which was unexpected considering the k_cat and K_m parameters measured for oxidation of DMN and DEN to the aldehydes and for oxidation of the aldehydes to the carboxylic acids. Spectral analysis did not indicate strong affinity of the aldehydes for P450 2A6, but pulse-chase experiments showed only limited exchange with added (unlabeled) aldehydes in the oxidations of DMN and DEN to carboxylic acids. Substoichiometric kinetic bursts were observed in the pre-steady-state oxidations of DMN and DEN to aldehydes. A minimal kinetic model was developed that was consistent with all of the observed phenomena and involves a conformational change of P450 2A6 following substrate binding, equilibrium of the P450-substrate complex with a non-productive form, and oxidation of the aldehydes to carboxylic acids in a process that avoids relaxation of the conformation following the first oxidation (i.e. of DMN or DEN to an aldehyde).     

Evaluating the influence of inhibitors present in lignocellulosic hydrolysates on the cell membrane integrity of oleaginous yeast Trichosporon fermentans by flow cytometry

The effect of ten typical organic acids and five aldehydes present in lignocellulosic hydrolysates on the cell membrane integrity of oleaginous yeast Trichosporon fermentans was evaluated by flow cytometry. Overall, organic acids affected the cell membrane integrity of T. fermentans more significantly than that of aldehydes albeit aldehydes are more toxic to T. fermentans. The PI (Propidium Iodide) uptake rate of T. fermentans’ cells gradually decreased as fermentation going on, indicating that T. fermentans could overcome the inhibition of organic acids or aldehydes by adaption. Interestingly, in some cases, the effect of organic acids or aldehydes on the cell membrane integrity of T. fermentans was well related to their hydrophobicity. However, for the outliers, no obvious similar phenomena were observed. Thus, the attack on hydrophobic sites of cell membrane was not the only determinant for the damage of organic acids or aldehydes on cell membrane integrity of T. fermentans.     

Partial purification of the NADPH-dependent aldehyde reductase from bovine cardiac muscle.

An aldehyde reductase catalyzing the NADPH-dependent reduction of long-chain aldehydes has been purified 690-fold from bovine cardiac muscle. Based on the results obtained during gel filtration, this enzyme has an apparent molecular weight of 34,000. The pI of the aldehyde reductase was 6.1 and the enzymatic activity had a sharp pH optimum at 6.4. The enzyme catalyzed the reduction of aromatic aldehydes and aliphatic aldehydes having eight or more carbon atoms. Short-chain aldehydes, aldoses, or ketoses or long-chain methyl ketones were not utilized as substrates by this enzyme. However, the methyl ketone, pentadecan-2-one, was a competitive inhibitor of this enzyme with an apparent K_i = 10 μm when tetradecanal was the variable substrate. The reaction was not reversible when ethanol or hexadecanol was employed as substrate, utilizing either NAD⁺, or NADP⁺ as a cofactor. The addition of 10 mm pyrazole to the incubation medium had no effect on the enzymatic activity.     

几种典型植物精油的化学成分与其抗菌活性

【目的】植物精油萃取自天然植物, 因具有抗菌活性, 近年来受到广泛关注。论文的目的是分析植物精油的化学成分, 测试其抗菌活性, 并研究其化学成分与抗菌活性之间的联系。【方法】实验选取了肉桂、山苍子、丁香、香茅、迷迭香和大蒜精油等6种典型植物精油, 通过气质联用分析方法研究了其化学组分, 并通过污染食物技术研究了其对黑曲霉和绳状青霉的抗真菌活性, 以及对大肠杆菌和金黄色葡萄球菌的抗细菌活性。【结果】气质联用分析结果表明, 肉桂、山苍子、香茅和迷迭香等4种植物精油的化学成分主要是醛类和醇类, 丁香精油的主要化学成分是丁香油酚, 大蒜精油化学成分基本上都是含硫的醚类, 其中二烯丙基三硫醚(大蒜素)含量最高。抗菌活性结果显示, 不同植物精油的抗菌活性不同, 6种植物精油的抗真菌活性由强到弱依次为: 肉桂>大蒜>丁香>山苍子=香茅>迷迭香, 抗细菌活性由强到弱依次为: 肉桂>山苍子>丁香>香茅=迷迭香>大蒜。【结论】植物精油的抗真菌、细菌活性与其化学组分密切相关, 肉桂、山苍子、香茅和迷迭香等4种精油的抗菌活性可能主要与其化学成分中的醛类和醇类有关, 丁香精油较高的抗菌活性可能主要源于丁香油酚; 大蒜精油具有高效的抗真菌活性主要源于其化学成分中的含硫醚。不同植物精油化学成分不同, 抗真菌、细菌活性也不同, 表明其可能有不同的抗真菌与抗细菌机制。     

Fatty acids,part 39: Oxymercuration-demercuration of unsaturated alcohols. A new procedure for the identification,isolation, and estimation of Δ3t, Δ4, and Δ5 alkenols and of substances reducible thereto

A new procedure for the identification, isolation, and estimation of Δ3t, Δ4, and Δ5 alkenols is based on the intramolecular reaction occurring when these compounds are submitted to oxymercuration-demercuration in dimethylformamide solution. This method can also be applied to aldehydes, acids, and esters after their reduction to alcohols and its use in the examination of some selected seed oils, tall oil, rat liver lipids, and some fish oils both before and after partial hydrogenation is reported.     

Epicuticular waxes of two sorghum varieties

The epicuticular waxes of the two sorghum varieties Alliance A and SD 102 have been analyzed, after separation of the leaf blades from the sheaths. The major constituents were found to be free fatty acids but small amounts of esters, aldehydes, alcohols, n-alkanes and sterols were also detected. The typical chain lengths of aldehydes, free alcohols and free fatty acids were C₂₈ and C₃₀.     

Variability in fatty acids and fatty aldehydes in different organs of two prosobranch gastropod mollusks

The distribution of fatty acids and fatty aldehydes of total lipids in mantle, foot and digestive gland of two prosobranch gastropod mollusks, Bellamya bengalensis and Pila globosa, from India were studied. The individual volatile compounds, e.g., acids and aldehydes, were separated by serially coupled capillary columns with different polarity stationary phase and identified by gas chromatography-mass spectrometry. Saturated fatty acids were the main components and vary from 48–60%, monoenic are 18–30%, while polyunsaturates vary between 21–33%. The digestive glands of both the snail species contained cyclopropane fatty acids, not previously reported in gastropods.     

Chirality and biosynthesis of lilac compounds in Actinidia arguta flowers

Biosynthesis of lilac compounds in ‘Hortgem Tahi’ kiwifruit (Actinidia arguta) flowers was investigated by treating inflorescences with d₅-linalool. The incorporation of the deuterium label into 8-hydroxylinalool, 8-oxolinalool, the lilac aldehydes, alcohols, and alcohol epoxides was followed by GC-MS and enantioselective GC-MS. Both (R)- and (S)-linalool were produced naturally by the flowers, but 8-hydroxylinalool, 8-oxolinalool, and the lilac aldehydes and alcohols occurred predominantly as the (S) and 5′(S)-diastereoisomers, respectively. The enantioselective step in the biosynthesis of the lilac aldehydes and alcohols was concluded to be the oxidation of linalool to (S)-8-hydroxylinalool. In contrast, the lilac alcohol epoxides had a 5′(R):(S) ratio, the same as for linalool, which suggests that either these compounds are not synthesised from the 5′(S)-configured lilac aldehydes and alcohols, or that if indeed they are, then it is by an enantioselective step that favours utilisation of the 5′(R)-configured compounds.