An efficient synthesis of the plant growth hormone 1-triacontanol

Summary A high yield synthesis of 1-triacontanol was based on the cheap and easily available starting materials 1-octadecanol and 1,12-dodecanediol. The first one was converted to octadecanal using a phase transfer system, whereas the second one after phase transfer bromination and reaction with triphenylphosphine provided 1-hydroxy-12-triphenylphosphonium bromide.Wittig reaction of these two synthons and subsequent hydrogenation furnished the desired product.

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Eine effiziente Synthese des Pflanzenwachstumshormons 1-Triacontanol

Zusammenfassung Eine Synthese von 1-Triacontanol, basierend auf den einfach zugänglichen Edukten 1-Oktadecanol und 1,12-Dodecandiol, die gute Ausbeuten ergibt, wird beschrieben. Ersteres Edukt wurde mit Hilfe eines Phasentransfersystems zu Oktadecanal umgesetzt. Letzteres gab nach Phasentransfer-Bromierung und Umsatz mit Triphenylphosphin 1-Hydroxy-12-triphenylphosphoniumbromid.Wittig-Reaktion dieser beiden Synthone und anschließende Hydrierung lieferte das erwünschte Produkt.

     

Analysis of volatiles emitted by potato plants by means of a Colorado beetle electroantennographic detector

An electroantennographic detector based on the antenna of the Colorado potato beetle (Leptinotarsa decemlineata Say, 1824) was used to investigate volatile organic compounds emitted by injured potato plants (Solanum tuberosum L., 1753). Samples were collected on charcoal traps using the CLSA method. Analyses were performed with a GC-EAD-FID setup as well as a GC-MS system. The experiments revealed that several groups of compounds are perceptible to the Colorado potato beetle. The ability of the Colorado potato beetle to detect green leaf odours (e.g. (Z)-3-hexen-1-ol and (E)-2-hexenal), linalool and some terpenes has been noticed before [Visser et al., J. Chem. Ecol. 5 (1979) 13]. In this work the presence of (Z)-3-hexen-1-ol, (E)-2-hexenal and linalool in the potato odour could be confirmed. Moreover, β-myrcene, benzeneethanol, and several sesquiterpenes (e.g. caryophyllene and germacrene-D) were identified. The GC-EAD experiments reveal that apart from the green leaf odours and linalool prominent reactions of the Colorado bettle antenna are induced by benzeneethanol and the sesquiterpene fraction.     

The discovery of novel auxin transport inhibitors by molecular modeling and three-dimensional pattern analysis

Summary Molecular modeling techniques and three-dimensional (3D) pattern analysis have been used to investigate the chemical and steric properties of compounds that inhibit transport of the plant hormone auxin. These compounds bind to a specific site on the plant plasma membrane characterized by its affinity for the herbicide N-1-naphthylphthalamic acid (NPA). A 3D model was derived from critical features of a set of ligands for the NPA receptor, a suggested binding conformation is proposed, and implications for the topographical features of the NPA receptor are discussed. This model, along with 3D structural analysis techniques, was then used to search the Abbott corporate database of chemical structures. Of the 467 compounds that satisfied the criteria of the model, 77 representative molecules were evaluated for their ability to compete for the binding of [³H]NPA to corn microsomal membranes. Nineteen showed activity that ranged from 16 to 85% of the maximum NPA binding. Four of the most active of these, representing chemical classes not included in the original compound set, were also found to inhibit polar auxin transport through corn coleoptile sections. Thus, this study demonstrates that 3D analysis techniques can identify active, novel ligands for biochemical target sites with concomitant physiological activity.     

α—（1H—1,2,4—三唑—1—基）—α—芳氧烷基芳乙酮的合成和生物活性研究

合成了２２个α－（１Ｈ－１，２，４－三唑－１－基）－α－芳氧烷基芳乙酮类新型化合物，所有化合物的结构经＾１ＨＮＭＲ和元素分析证实；初步的生物活性测试结果表明，该类化合物具有一定的杀菌活性和植物生长调节活性。     

A preliminary study of plant aroma profile characteristics by a combination sampling method coupled with GC-MS

Plant aroma profile characteristic is an important bio-information. In this study, a sampling method in combination with headspace solid phase microextraction (HSSPME), simultaneous distillation extraction (SDE) and steam distillation (SD), followed by gas chromatography-mass spectrometry (GC-MS) detection, was used to study the aroma profile characteristics of the fresh and stale samples of common tomato, cherry tomato, durian and longan, and of the different samples of Chinese mango and Allium varieties. The typical aroma volatiles of these samples were isolated and identified according to the different degrees of certainty. The different samples showed different aroma profile characteristics when principal component analysis (PCA) was conducted to analyze the data of the aroma profile chromatograms. Then the crucial aroma volatiles contributing greatly to the clustering differences of the aroma profile characteristics of the fresh and stale common tomato, cherry tomato, durian and longan were identified by common model strategy. These compounds are potential bio-markers of plant metabolism, but further study is needed. Continuous investigations for the aroma profile characteristics of common tomato during storage and chive during growth were conducted to distill the potential bio-information from the plant metabolism processes. The saturated hexanal of common tomato increased during storage, whereas the unsaturated hexenal reduced. The accumulating trends of volatile sulfides were observed during chive growth. The preliminary results related with the corresponding bio-information could provide helpful clues to the study of plant's secondary metabolism process and benefit quality control.     

Determination of Phenolic Acids in Herba Epilobi by ITP–CE in the Column-Coupling Configuration

The combination of capillary isotachophoresis (ITP) and capillary zone electrophoresis (CZE) in the column-coupling configuration has been optimized in a mode in which the background electrolyte employed in the CZE step was different from the leading and terminating electrolytes of the ITP step. The optimum composition of the electrolyte system was 0.01 M HCl, 0.02 M IMI, 0.2% HEC, pH 7.2 (leading electrolyte), 0.01 M HEPES, pH 8.2 (terminating electrolyte), and 25 mM MES, 50 mM TRIS, 30 mM boric acid, 0.2% HEC, pH 8.3 (background electrolyte). All solutions contained 20% methanol. The timing of the transfer of isotachophoretically stacked analyte zones into the CZE column was also optimized. An ITP–CZE method with UV detection at 270 nm was developed for separation of nine phenolic acids (protocatechuic, syringic, vanillic, cinnamic, ferulic, caffeic, ρ-coumaric, chlorogenic, and gentisic acids) in a model mixture and used for assay of some of these acids in a methanolic extract of herba epilobi. Application of ITP–CZE resulted in 100-fold better sensitivity than conventional CZE; limits of detection ranged between 10 and 60 ng mL⁻¹. When MES–TRIS–borate-based buffer, pH 8.3, was used in the CZE separation step the linearity of the ITP–CZE response was satisfactory (correlation coefficients were from 0.9937 to 0.9777). Repeatability was also satisfactory (RSD values ranged between 0.77% and 1.28% for migration times and between 1.65% and 13.69% for peak area). Revised: 23 March and 27 April 2006     

Plant-based food hydrogels: Constitutive characteristics,formation, and modulation

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Determination of inorganic anions, carboxylic acids and amino acids in plant matrices by capillary zone electrophoresis

Summary Physiological investigations of solute transport in plants affords knowledge of solute distribution between different tissues. Capillary electrophoresis using indirect UV and laser induced fluorescence (LIF) detection is demonstrated as a useful technique for the simultaneous determination of inorganic anions, amino acids and carboxylic acids in plant samples. Cell sap obtained from plant tissues as well as simple ethanolic or aqueous plant extracts can be analysed directly without any pretreatment. This matrix stability and the very small volumes required allow fast determinations of various compounds in small plant tissue sections. In the case of carboxylic acids, resolution can be optimized using calcium for selective complexation of some of the compounds. Selective and sensitive determination of amino acids is possible using precolumn derivatisation with orthophthaldialdehyde (OPA) and laser induced fluorescence detection. Presented at the 21^st ISC held in Stuttgart, Germany, 15^th–20^th September, 1996     

Investigation of phenolic acids in yacon (Smallanthus sonchifolius) leaves and tubers

Thin-layer chromatographic (TLC) screening of crude extracts of dried leaves and tubers of yacon (Smallanthus sonchifolius, Asteraceae) and products of acid hydrolysis of tubers on the silica gel HPTLC plates using the developing solvents ethyl acetate-formic acid-water (85:10:15, v/v/v) and n-hexane-ethyl acetate-formic acid (20:19:1, v/v/v) proved the presence of chlorogenic, caffeic and ferulic acid. These phenolic acids were isolated from the crude extract of yacon leaves by preparative TLC, and identified after elution by HPLC/MS, as well as by direct injection of the crude extract into the HPLC/MS system. Acid hydrolysis of tubers released the increased amount of phenolic acids (e.g. caffeic acid and ferulic acid), flavonoid quercetin and an unidentified flavonoid, which was detected by TLC analysis. Ferulic acid, isomers of dicaffeoylquinic acid and still an unidentified derivative of chlorogenic acid (Mr = 562) as constituents of yacon leaves and ferulic acid as constituent of yacon tubers are reported here for the first time. These acids gave significant contribution to the radical scavenging activity detected directly on the TLC plate sprayed with 1,1-diphenyl-2-picrylhydrazyl (DPPH).     

High-performance liquid chromatographic analysis of secoisolariciresinol diglucoside and hydroxycinnamic acid glucosides in flaxseed by alkaline extraction

A HPLC method was developed for the analysis of secoisolariciresinol diglucoside (SDG) and hydroxycinnamic acid glucosides in milled defatted flaxseed flour. Direct extraction by 1 M NaOH for 1 h at 20 degrees C resulted in a higher yield than that obtained by hydrolysis of alcoholic extracts. An internal standard, o-coumaric acid, was used and the method was found to be easy, fast, and with good repeatability. On dry matter basis, different samples of flaxseeds varied considerably in their content of (+)-SDG (11.9-25.9 mg/g), (-)-SDG (2.2-5.0 mg/g), p-coumaric acid glucoside (1.2-8.5 mg/g), and ferulic acid glucoside (1.6-5.0 mg/g).