Study on the Composition and Physiological Activity of the Essential Oils and Extracts of Cinnamomum camphora Fruit

Supercritical carbon dioxide (SC-CO₂), hydrodistillation (HDO), ethanol extraction (EE), and petroleum ether extraction (PE) were used to extract the essential oil and extracts of Cinnamomum camphora fruit in this study. Gas chromatography-mass spectrometry was used to identify the volatile components of essential oils and extracts, and 63 compounds were identified. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assay and Ferric reducing ability of plasma (FRAP) assays and the inhibition experiment of bacteria and fungi (Staphylococcus aureus (S. aureus), Hay bacillus (H. bacillus), Escherichia coli (E. coli), Aspergillus niger (A. niger), Candida albicans (C. albicans)) showed these essential oils and extracts indicated antioxidant and antibacterial activities. S. aureus was the most sensitive to the essential oil (MIC=0.08 mg/ml). Combined with the Brine Shrimp Lethality Test (BSLT) experiment, HDO (LD₅₀=68.21 μg/ml) was considered to have the most potential natural preservative. Subsequently, the inhibitory mechanism of HDO on bacteria and fungi was explored through extracellular conductivity and SEM, and the possibility of HDO to preserve the freshness of bananas was verified through banana shelf-life experiments. The results suggested these essential oils and extracts of Cinnamomum camphora fruit indicated effectively inhibit the growth of microorganisms on the surface of bananas, extend the shelf-life, and have the potential to become a natural antiseptic ingredient.     

Preparation of Optically Active Allothreonine by Separating from a Diastereoisomeric Mixture with Threonine

A simple procedure is described to obtain D- and L-allothreonine (D- and L-aThr). A mixture of N-acetyl-D-allothreonine (Ac-D-aThr) and N-acetyl-L-threonine (Ac-L-Thr) was converted to a mixture of their ammonium salts and then treated with ethanol to precipitate ammonium N-acetyl-L-threoninate (Ac-L-Thr·NH₃) as the less-soluble diastereoisomeric salt. After separating Ac-L-Thr·NH₃ by filtration, Ac-D-aThr obtained from the filtrate was hydrolyzed in hydrochloric acid to give D-aThr of 80% de, recrystallized from water to give D-aThr of >99% de. L-aThr was obtained from a mixture of the ammonium salts of Ac-L-aThr and Ac-D-Thr in a similar manner.     

Characterization of Starch Granules from Waxy,Nonwaxy, and Hybrid Seeds of Amaranthus hypochondriacus L.

Perisperm starch granules of the dicotyledonous plant Amaranthus hypochondriacus L. were prepared from two homozygous lines (WxWx and wxwx) and their hybrid (Wxwx). The hybrid line was obtained by natural hybridization. By Sephadex G-75 column chromatography of isoamylase-debranched starches, the amylose content of WxWx starch was 16.9%, that of Wxwx was 10.7, and wxwx was zero. SDS-polyacrylamide gel electrophoresis showed that starch granules from two genotypes (WxWx and Wxwx) contained a Wx protein (MW = 68,000) which was supposed to be a starch granule-bound starch synthase and was associated with amylose synthesis, as observed in nonwaxy maize. The intensities of the stained protein bands were apparently correlated with the number of the Wx alleles. The Wx protein was not detected in the wxwx starch. These findings suggest that the Wx allele produces the Wx protein and amylose in the perisperm of A. hypochondriacus, with incomplete dominance over the wx allele. The Wx allele did not affect the fine structure of amylopectin and had little if any effect on susceptibility to glucoamylase and pasting properties of starch granules from these genotypes.     

Isolation and Chemical Structures of Two New Catechins from Fresh Tea Leaf

A total of 20 volatile organic compounds from the peel of citrus fruit Ohshima no. 1 were identified by gas chromatography-mass spectrometry (GC-MS). The amount of limonene in Ohshima no. 1 was lower than those in the parent cultivars, Miyauchi iyokan and Yoshiura ponkan, whereas those of γ-terpinene, linalool, sabinene, p-cymene, and terpinolene in Ohshima no. 1 were somewhat higher. However, comparing the results, it was found that volatile components from both parent cultivars were present in the peel of Ohshima no. 1. Principal component analysis (PCA) of data obtained with an electronic nose indicated that the odor of Ohshima no. 1 showed a clear upward displacement as compared with those of parent cultivars in PC1. The oils of Miyauchi iyokan and Yoshiura ponkan showed displacement in a negative direction, and a positive one in PC2. By PCA analysis, it was found that the odor quality of Ohshima no. 1 was very different from those of the parent cultivars.     

Interaction of air ions and bactericidal vapours to control micro-organisms

AIMS: The aim of this study was to investigate the antibacterial activity of candles containing specific-antibacterial compounds, such as essential oils and their constituent compounds. The importance of the ionization products from the flame and the aerial concentration of the volatile compounds were investigated. METHODS AND RESULTS: Agar plates inoculated with Escherichia coli (DH5alpha) or Staphylococcus aureus (NCTC strain number 8532) were exposed in a large air-tight chamber to candle flames combined with the volatile bactericidal compounds beta-pinene and orange oil. A steady decline in E. coli numbers was observed over time because of the effect of a candle flame. This was significantly increased by the addition of volatile oils. The number of S. aureus colonies was not reduced by a plain candle, but significant reductions were caused following exposure to beta-pinene and orange oil candles. As aerial concentration of the volatiles was increased the viability of E. coli and S. aureus declined. Ionization products from the flame made a significant contribution to the observed effects, as intercepting the ions on a grounded grid over the agar plates allowed at least 20% more cells to survive. CONCLUSIONS: This study demonstrates the antibacterial properties of ionization products from a candle flame, and that this effect can be significantly increased by the addition of specific-antibacterial compounds, such as orange oil and beta-pinene. The role of both the ionization products from the candle flame and the concentration of volatile compounds released are important to the effect. SIGNIFICANCE AND IMPACT OF THE STUDY: The technique described here offers a new and novel technique for reducing the concentration of bacteria on surfaces.     

生姜精油化学成分及其抗菌活性

[背景]随着耐药微生物种类的增多和耐药性增强,抗耐药微生物新药的发现已成为全球关注的问题.生姜精油是纯天然植物精油,是天然抗菌材料的优选.[目的]分析生姜精油的化学成分,研究生姜精油对常见条件致病菌抗菌活性的影响,并阐明其可能的抗菌机制.[方法]采用气相色谱/质谱技术(Gas Chromatography/Mass S...     

Mandarin essential oil as an antimicrobial in ethanolic fermentation: Effects on Limosilactobacillus fermentum and Saccharomyces cerevisiae

The antibacterial activity of citrus essential oils (EOs) in the context of combating Limosilactobacillus fermentum, one of the most important bacterial contaminants in the bioethanol production industry, has never been explored previously. Industrial processes usually utilize sulfuric acid for cell treatment to decrease bacterial contamination. However, due to the hazardous nature of sulfuric acid, an alternative to it is highly desirable. Therefore, in the present study, the efficacy of Fremont IAC 543 mandarin EO against a strain of L. fermentum (ATCC^® 9338™) was evaluated under proliferative/nonproliferative conditions, in both pure culture and co-culture with an industrial strain of Saccharomyces cerevisiae. The mandarin EO exhibited higher effectiveness against L. fermentum compared to that against S. cerevisiae under nonproliferative conditions (added to water rather than to culture medium). At the concentration of 0·05%, the EO was as effective as the acid solution with pH 2·0 in reducing the count of L. fermentum almost 5 log CFU ml^–1 cycles, while the concentration of 0·1% led to the complete loss of bacterial culturability. When L. fermentum was co-cultured with S. cerevisiae, the efficacy of the EO against the bacterial strain was reduced. However, despite this reduced efficacy in co-culture, mandarin EO may be considered effective in combating L. fermentum and could be applied in processes where this bacterium proves to be unfavourable and does not interact with S. cerevisiae.     

NMR Spectra of Glutamic Acid-containing Dipeptides in Relation to Sequence Determination

It is possible to determine the sequence of a dipeptide containing glutamic acid as a constituent and also to decide whether the glutamyl bond is α or γ when glutamic acid is the N-terminal component by measuring the NMR spectra of the peptide in acidic, aqueous and basic solutions.     

Essential Oil Compositions and Antibacterial and Antioxidant Activities of Five Lavandula stoechas Cultivars Grown in Thailand

The essential oils of five Lavandula stoechas cultivars grown in Thailand were characterized for their volatile compounds using GC‐FID and GC/MS methods as well as screened for antibacterial and antioxidant activities. Dried aerial parts, including flowers and stems from each cultivar, were subjected to hydrodistillation for 4 h. The essential oil yields were 0.18 %–0.82 % w/w. Of the 95 compounds detected and identified, 1,8‐cineole, fenchone, and camphor were considered the major compounds. Essential oil from each cultivar demonstrated different patterns of antibacterial activity and a variety of antioxidant properties. The highest antibacterial activity, MIC=0.39 mg mL^?1, was observed from the essential oil of L. stoechas ‘major’ (against Klebsiella pneumoniae and Salmonella typhimurium) and the essential oil of L. stoechas ‘white lavender’ (against S. typhimurium). The essential oil of L. stoechas×viridis ‘St. Brelade’ possessed the highest antioxidant capacity, as determined by the DPPH and ABTS assays (IC₅₀ of 67.65 and 89.26 mg mL^?1, respectively). The results indicated that some of these essential oils could be used as key ingredients in lavender oil products in Thailand to increase their therapeutic efficacy, depending on their intended application.     

Systematic Evolutional Relation of Chemical Components of the Essential Oils from 11 Taxa of Citrus Leaves

With fused silica capillary column for GC, according to Kovats retention index ITP of GC and GC-MS-DS double identification, chemical components of the essential oils from 11 taxa in Citrus leaves were studied. It has been found that the characteristic component of Papeda seedon is citronellal; that of ilurantiurn section is “myrcene and linalool” or “sabinene and liaalool”; that of Microacrumen subsection is linalool; that of Macroacrumen subsection is Z-, E-liaalooloxide and that the characteristic components of Citrophorum section are neral and geranial and those of Cephalocitrus section are neral, geranial and carvone. Our study indicates that there are different GC configurations for various taxonomic units. The differences narrow from sections to species and from species to cultivars. The differences are greatest among sections and remarkable among different species of the same section. Different culativars of the same species of the same section have similar Gig patterns. All these differences or similarities reflect their close or distant relationships, which are the important bases for setting up natural classification. The systematic evolution of the sections of genus Citrus may correlate well with the characteristic components, the biosynthesis pathways and the morphological characters.     

秦岭油松针叶挥发性物质的成分分析

采用水蒸（蒸馏法和GC／MS方法对秦岭林区油松针叶挥发成分进行分析测定,鉴定出油松针叶中65种挥发性成分,其化学成分以萜烯类(79．39%)、酯类(9．16％)、醇类(10．36％)、醛类(0．25%)等为主,化合物则以α-蒎烯(5．92％)、β-蒎烯(6．09％)、乙酸龙脯酯(8．69%)、β-石竹烯(28．62%)、α-石竹烯(5．97%)、α-杜松醇(3．27％)、异杜松醇(3．44％)、萜烯醇(2．2j％)、杜松二烯(11．33%)为主。     

小叶臭黄皮叶挥发油化学成分的研究

采用水蒸气蒸馏法提取小叶臭黄皮叶挥发油,运用毛细管气相色谱-质谱联用法对挥发油成分进行了分析,共分离出84个峰,鉴定了其中的66种成分,所鉴定成分占挥发油总量的94.52%.其主要化学成分为α-芹子烯(15.76%)、石竹烯(15.05%)、β-芹子烯(9.54%)、α-蒎烯(6.43%)和α-石竹烯(5.39%)等.     

Essential Oil of Lavender Inhibited the Decreased Attention during a Long-Term Task in Humans

This study examined the effects of odors on sustained attention during a vigilance task. Two essential oils (lavender and eucalyptus) and two materials (l-menthol and linalyl acetate) were compared with a control. The increase in reaction time was significantly lower with lavender than with the control. The results suggest that the administration of lavender helped to maintain sustained attention during the long-term task.     

Effects of volatile compounds on arthrospore germination and mycelial growth ofGeotrichum candidum citrus race

Three groups of volatile compounds, i.e., alcohols, aldehydes and esters, were tested for their effects on arthrospore germination and mycelial growth ofGeotrichum candidum citrus race, the causal agent of citrus sour rot. Alcohols (heptanol, octanol, nonanol, decanol, geraniol, citronellol) at a concentration of 1.0 μl/ml showed 60% or more inhibitory effects on both germination and mycelial growth of this pathogen. Among aldehydes tested, only citral had an inhibitory effect of more than 50%, while esters had no effect. The chain length of straight-chain (C6–C12) alcohols correlated with inhibitory effect, and nonanol (C9) was most active. Treatment with alcohols or citral prior to inoculation reduced colonization and maceration of lemon peel by this pathogen by 70% or more. Results suggested that alcohols or citral can probably be used to prevent the development of citrus sour rot.     

GC/MS法分析核桃叶挥发油化学成分

利用水蒸气蒸馏方法从陕西栽培的核桃品种西洛3号提取了核桃叶挥发性物质,用GC／MS法分离确定出20种化学成分,其中主要成分(相对含量)为萜类(84．89％)、芳香烃(3．9％)和酯类(1．34％)化合物,占总检出量约90．84％。     

Evaluation of Characteristic Aroma Compounds of Citrus natsudaidai Hayata (Natsudaidai) Cold-Pressed Peel Oil

The characteristic aroma compounds of Citrus natsudaidai Hayata essential oil were evaluated by a combination of instrumental and sensory methods. Sixty compounds were identified and quantified, accounting for 94.08% of the total peel oil constituents. Limonene was the most abundant compound (80.68%), followed by γ-terpinene (5.30%), myrcene (2.25%) and α-pinene (1.30%). Nineteen compounds which could not be identified in the original oil were identified in the oxygenated fraction. Myrcene, linalool, α-pinene, β-pinene, limonene, nonanal, γ-terpinene, germacrene D, and perillyl alcohol were the active aroma components (FD-factor > 3⁶), whereas β-copaene, cis-sabinene hydrate and 1-octanol were suggested as characteristic aroma compounds, having a Natsudaidai-like aroma in the GC effluent. Three other compounds, heptyl acetate, (E)-limonene oxide and 2,3-butanediol, which each showed a high RFA value (>35) were considered to be important in the reconstruction of the original Natsudaidai oil from pure odor chemicals. The results indicate that 1-octanol was the aroma impact compound of C. natsudaidai Hayata peel oil.     

鸡屎藤挥发油化学成分的研究

利用气相色谱－质谱联用（ＧＣ／ＭＳ）技术对鸡屎藤挥发油化学成分进行分析研究,初步鉴定了３１种成分,它们占挥发油总量的７７．１６％,其中含量友上的有乙氧戊烷、乙酸异戊酯、苯甲醛、己酸乙酯、甲酸苯甲酯、乙酸苯甲酯、乙酸－２－苯乙酯、５,６,７,７ａ－四氢－４,４,７ａ－三甲基－２（４Ｈ）－苯并呋喃酮、十五碳酸乙酯、十六碳酸和癸酸异戊酯等１１种成分。     

柚皮干制前后精油香气成分分析

为明确干制对柚皮中精油香气成分的影响,采用水蒸气蒸馏法提取干制前后柚皮中精油,通过气相色谱-质谱法（GC-MS）对精油进行成分分析.结果表明,从鲜柚皮中共检出74种香气成分,占精油总质量分数的99.61%;从干柚皮中共检出45种香气成分,占精油总质量分数的99.45%;两者共有香气成分44种,相对质量分数分别为98.16%和99.41%.干制后柚皮香气成分中烯烃类化合物的相对质量分数增加;醇类、酯类和酮类化合物的相对质量分数减少.干制对柚皮主体香气成分影响不大.     

Formation of 2-Aminobutanoic Acid from Threonine and Methionine by Mixed Rumen Ciliate Protozoa

Precursors of 2-aminobutanoic acid (2-ABA), found in the incubation medium of mixed rumen ciliate protozoa, were examined with washed or starved bacteria-free ciliates. Threonine and methionine strongly stimulated the formation of 2-ABA. Formation of 2-ABA by direct conversion of threonine and dethiomethylation of methionine was confirmed by radiotracer experiments with [U-¹⁴C]L-threonine and [carboxyl-¹⁴C] and [methyl-¹⁴C]L-methionine.     

Purification and Properties of Allothreonine Aldolase from Maise Seedlings

In order to elucidate the structure-activity relationship of griseofulvin (1), (±)-6′-demethyl analog (3), 2′-demethoxy-6′-demethyldihydro analog (4), (±)-dechloro-6′-ethyl analog (5), (±)-dechloro-6′-epi-ethyl analog (6), (±)-6′-ethyl analog (7) and (±)-6′-epi-ethyl analog (8) were synthesized by a Diels-Alder cycloaddition of alkylidene ketones (16, 17, 18, 19 and 20) with modified 1,3-butadienes (21 or 22). Their biological activities were examined against fungi.