首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
The lipid composition of the seeds ofSecurinega suffruticosa (Euphorbiaceae) has been studied, and eight classes of lipids have been identified with a predominance of triacylglycerols; the fatty acid compositions and structures of the triacylglycerols have been determined. Among the hydroxy acids of the hydroxyacylglycerols 13 components belonging to saturated, monoenic, and dienic acids of the C17, C18, and C20 series have been identified; 12-hydroxyheptadecanoic and 12-hydroxyeicosanoic acids are new.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 277–281, May–June, 1986.  相似文献   

2.
The composition of the fatty mono- and dihydroxy acids of the fruit ofRumex paulsenianus Rech. fil. (familyPolygonaceae) has been determined by a combination of IRS, UVS, GLC, and mass-spectrometric methods. (22) Monohydroxy acids of the C14–C20 series, including isomers and isologues, and four dihydroxy acids from C18 to C20, including a new isomeric 9-OH-10, 12–17:2 acid have been detected.Institute of the Chemistry of Plant Substances, Uzbek Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 762–765, November–December, 1991.  相似文献   

3.
Extraction of the comminuted seeds has yielded an oil from which have been isolated: C33-C25, C18 and C17 paraffinic hydrocarbons, C18:1, C18:2, C18:3, C17:1, C17:2 and C17:3 olefinic hydrocarbons, ethyl esters of C32:0, C31:0, C30:0, C29:0, and C28:0 fatty acids, sterols with molecular weights of 414, 412, and 400, and the alcohols -amyrin and lupeol with their natural acetates. Extraction of the uncomminuted seeds has shown that the paraffinic hydrocarbons, ethyl esters, and alcohol acetates pass into the oil from the husks of the seeds. This is the first time that the C31:0 and C29:0 fatty acids have been detected as natural compounds, and it is the first time that the ethyl esters of C34, C33, C32, C31, and C30 fatty acids have been isolated from seed oils of higher plants.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 612–615, September–October, 1979.  相似文献   

4.
The structures of the oxygenated fatty acids of the lipids ofOnopordum acanthium L. seeds have been studied by the methods of chemical, chromatographic, and spectral analyses. Triepoxy acids of the C18 series and 24 monohydroxy acids with chain lengths of C14–C18 have been identified, of which the 8-OH-9Z,12Z-18:2 and the 14-OH-9Z,12Z-18:2 acids have been isolated as natural compounds for the first time.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 515–518, July–August, 1993.  相似文献   

5.
Summary Atmospheric precipitation and aerosol samples are characterized by a complex mixture of several organic compounds. A simple method for the simultaneous determination of the main compound classes by GC/MS is presented. In detail, seasonal variations of C8–C32 fatty acids in precipitation in a semirural area have been studied. Total fatty acids concentrations of 7–53 g/l were detected. Summer rain is characterized by high amounts of fatty acids >C20 and lower amounts of C11–C20 species. Two effects may be responsible: larger emission rates of fatty acids during vegetation periods and an increased influence of vapour phase due to higher temperatures during summer. CPI values showed no general trend; lower CPI values for winter rain could not be observed. This would be expected if anthropogenic sources play an important role. Monounsaturated fatty acids (C16:1, C18:1) were more abundant during winter than in summer. High concentrations of polyunsaturated fatty acids (C18:x) could be detected during summer. High relative concentrations of the potential oxidation products of the unsaturated species, nonanedioic acid and w-oxononanoic acid, are associated with relatively low concentrations of their precursors.  相似文献   

6.
Summary 1. It is desirable to analyze the composition of the organic acids of CO2 spice extracts after their preliminary separation into individual groups according to their physicochemical properties: steam-volatile, ester-bound obtained after the hydrolysis of esters of nonglyceride nature, and acids forming components of the triglycerides.2. Characteristic for the fraction of steam-volatile free acids and for the ester-bound acids in the CO2 extracts obtained after the hydrolysis of esters of nonglyceride nature are the C1–C7 low-molecular-weight saturated acids of the alipatic series: formic, isovaleric, valeric, caproic, etc. The higher fatty acids present include acids with even and odd numbers of carbon atoms from C8 to C18 and also acids with saturated and unsaturated bonds.3. The compositions of the lower acids in the extracts of all the samples studied are qualitatively very similar. Their quantitative compositions differ fundamentally. At the same time, differences both in the qualitative and in the quantitative compositions of the glyceride acids of the samples investigated are more pronounced. This is due to the circumstance that fruit was subjected to extraction in one case and leaves and rhizomes in another.Krasnodar Scientific-Research Institute of the Food Industry. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 763–767, November–December, 1977.  相似文献   

7.
The fatty acid compositions of five species and the compositions of the triacylglycerols of 22 species of the family labiatae have been studied for the first time. Octadeca-12,13-dienoic acid has been detected in five species. The typical compositions of the triacylglycerols differs from those of known plant oils with a similar set of fatty acids by the absence of triacylglycerols of the S3 type and the presence of the S2U type (0.1–1.6%). The main types are SU2 (5–24%) and U3 (74–95%). In a comparison of the position-species composition of the oils studied it was found that the oils of the plants of this family are distinguished by a greater diversity of species of triacylglycerols and also by the nature of the distribution of the unsaturated acyl residues between the 1,3- and 2-positions. In the majority of oils studied, the 2- position is enriched with the 18:1 acid, while the 18:2 acid is distributed predominantly in the 1,3- positions, and the nature of the distribution of the 18:3 acid is determined by its proportion in the total.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 618–625, September–October, 1979.  相似文献   

8.
The composition and amounts of liposoluble substances in the flesh and peel of feijoa fruit has been investigated. About 30 groups of lipid substances have been identified. The main groups of lipids in the flesh were triacylglycerols, sterols, cerebrosides, ceramide phosphate inositol oligosides, sulfoquinovosyldiacylglycerols, phosphatidic acids, phosphotidylglycerols and phosphatidylcholines. In the peel, hydrocarbons, sterols, esters of fatty acids and lower alcohols, cerebrosides, digalactosyldiacylglycerols, ceramide oligosides, phosphatidylglycerols, and include predominated. The fatty acids of the flesh were found to include 15 representatives (C12:0–C28:0), and those of the flesh 11 representatives tives (C12:0–C18:3).M. V. Lomonosov Technological Institute of the Food Industry, Odessa. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 464–467, July–August, 1991.  相似文献   

9.
Extraction of the comminuted seeds has yielded an oil from which have been isolated: C33-C25, C18 and C17 paraffinic hydrocarbons, C18:1, C18:2, C18:3, C17:1, C17:2 and C17:3 olefinic hydrocarbons, ethyl esters of C32:0, C31:0, C30:0, C29:0, and C28:0 fatty acids, sterols with molecular weights of 414, 412, and 400, and the alcohols α-amyrin and lupeol with their natural acetates. Extraction of the uncomminuted seeds has shown that the paraffinic hydrocarbons, ethyl esters, and alcohol acetates pass into the oil from the husks of the seeds. This is the first time that the C31:0 and C29:0 fatty acids have been detected as natural compounds, and it is the first time that the ethyl esters of C34, C33, C32, C31, and C30 fatty acids have been isolated from seed oils of higher plants.  相似文献   

10.
Summary The chromatographic behavior of twelve dansyl DL amino acids, one D isomer and eleven L isomers on RP18W/UV254, RP18W/F254s, and Sil C18–50 UV254 plates developed with aqueous—organic solutions containing bovine serum albumin (BSA) as chiral complexing agent has been extensively investigated. Enantiomeric resolution is highly dependent on mobile phase pH and ionic strength, and on the concentration of both BSA and organic modifier. All the racemates have been resolved within a development time of 1 h 30 min. The selectivity factors () for the dansyl amino acids have been compared with those from planar chromatography for the corresponding DNP, DNPy, and Fmoc amino acids, and with those of the same dansyl derivatives on a column prepared from BSA bound to silica gel.  相似文献   

11.
Mass spectra of peracetylated mycosides G′ and A′ are characterised by rearranged oxonium ions, corresponding to deoxysugars which have lost an acyl chain by fragmentation in the mass spectrometer. The main carboydrate constituent of mycoside G′ is a deoxysugar with one acyl chain and a methyl group. Mycoside A′ contains deoxysugars with one acyl chain and 0, 1 or 2 methyl groups. Deoxysugars with no acyl chains and one (G′, A′) or two (A′) methyl groups are also present. The mass spectra indicate that the acyl chains might be of the mycolic type: Peaks which might correspond to a fragmentation on both sides of the methyl branching are present and the CH+˙?C? C22H45 fragment, found in the spectrum of paracetylated mycoside A′ is characteristic of the branched chain. The highest peaks (m/e 1072 and 1100) in the spectrum of paracetylated mycoside A′ can be due to a mycolic chain after loss of acetic acid, methanol and H (l) on loss of acetic acif and H (m). The nature and abundance of the mycocerosic acids which esterify the aglycones can be deduced from the same spectra, as well as the structure of these aglycones which has been established previously by degradation and mass spectrometry. In order of decreasing abundance, C27 and C24 mycocerosic acids are present in mycoside G′, and C29, C32, C32, C30 and C27 mycocerosic acids are found in mycoside A′.  相似文献   

12.
A new empirical method is proposed to evaluate the average molecular polarizabilities assuming the additivity of atomic static polarizability. Atomic static polarizability for each atom in a particular valence state is obtained. Calculated molecular polarizabilities of 94 non-halogenated compounds and of the bases in nucleic acids show the excellent agreement with experimental data.To check the further validity of this method, dispersion coefficients for CH4, C2H6, C3H8,n–C4H10,n–C5H12,n–C6H14,n–C7H16,n–C8H18, H2, H2O and NH3 are obtained from a sum of atomic terms using a London-type formula, and are compared with the accurate values of dipole oscillator strength distribution (DOSD) method. The results show the excellent agreement between theory and experiment.  相似文献   

13.
The mononuclear Au(III)-complex ([Au(C18H18N2O4)Cl]) and hydrogensquarate ([C22H21N2O8]) of dipeptide phenylalanyltyrosine (H–Phe–Tyr–OH) have been synthezised, characterized spectroscopically and structurally by means of solid-state linear-polarized IR-spectroscopy, 1H- and 13C-NMR, ESI-MS, HPLC-MS–MS, FAB-MS, TGS and DSC methods. The structure of the Au(III)-complex has been predicted theoretically by DFT calculations. The dipeptide coordinated in a tridentate manner via –NH2, –COO and N-groups. One Cl ion is attached to the metal centre as a terminal ligand, yielding a planar AuN2OCl chromophor. The hydrogensquarate consists in positive charged dipeptide moiety and negative one hydrogensquarate (HSq) anion stabilizing by strong intermolecular hydrogen bonds.  相似文献   

14.
The original lipid content of the thylakoid membranes of moss Marchantia polymorpha has been determined for the first time. In particular, the content of SQDG is almost 3 times higher than those for both of the other classes. The ratios for DGDG and MGDG are just a little bit lower than those for green algae, but almost 2 times less than those for plants. The distribution of unsaturated bonds has changed in C18 -residues of fatty acids. The total content of C18-residues in thylacoid lipids have been almost the same but the content of C18:1, C18:2 and C18:3 are altered in the fractions of DGDG, PG and PE. The light stress produces only the quantitative, but no qualitative, changes of the thylakoid lipid composition. The properties of the thylakoid lipids and corresponding fatty acids in the monolayers at the liquid/gas interfaces have been studied. The changes in distribution of unsaturated bonds in C18 residues of fatty acids at light stress have been confirmed by Langmuir method.  相似文献   

15.
Summary A multicomponent extraction/concentration procedure has been developed for the enrichment of PCBs, PCTs and aliphatic hydrocarbons (pristane, C18, C19, C20, C22, C24, C28, C32 and C36) in pork liver. These components of the enriched extract were then simultaneously determined by gas chromatography. Mean recoveries ranged from 81.5% for pristane to 93% for PCBs;CV% (0.9–6.7) indicated the method to be both precise and reproducible.  相似文献   

16.
Polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are essential fatty acids. PUFA synthases are composed of three to four subunits and each create a specific PUFA without undesirable byproducts. However, detailed biosynthetic mechanisms for controlling final product profiles have been obscure. Here, the bacterial DHA and EPA synthases were carefully dissected by in vivo and in vitro experiments. In vitro analysis with two KS domains (KSA and KSC) and acyl‐acyl carrier protein (ACP) substrates showed that KSA accepted short‐ to medium‐chain substrates while KSC accepted medium‐ to long‐chain substrates. Unexpectedly, condensation from C18 to C20, the last elongation step in EPA biosynthesis, was catalyzed by KSA domains in both EPA and DHA synthases. Conversely, condensation from C20 to C22, the last elongation step for DHA biosynthesis, was catalyzed by the KSC domain in DHA synthase. KSC domains therefore determine the chain lengths.  相似文献   

17.
Summary The positions of the signals from the C3, C5, C6, and C7 carbon atoms in the13C NMR spectrum of coumarin have been established with the aid of information obtained from the13C NMR spectra of [3-D]-, [4-D]-, and 7-methoxycoumarins and by the use of an additive calculation based on the increments of the methoxy group in the13C NMR spectrum of anisole.M. V. Lomonosov Moscow State University Scientific-Research Institute of Pharmacology, Academy of Medical Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 458–462, July–August, 1975.  相似文献   

18.
Summary Two new diterpenoids have been isolated fromMarrubium peregrinum L.: a bicyclic diol C20H36O2, peregrinol — and a hydroxyketolactone C20H25O5, peregrinin. A substance C19H18O6 has been obtained as a by-product.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 4, pp. 249–251, 1966  相似文献   

19.
The seed coats ofArtemisia absinthium andOnoporum acanthium have been shown to contain paraffinic hydrocarbons (C31-C25 and C31-C27, respectively), wax esters (C32-C23 and C51-C33), acetyltriterpenols (six types, five types), and acyltriterpenols with a predominance of palmitoyltriterpenols (esters of higher saturated unbranched C32:0-C12:0 fatty acids and triterpenols with a molecular weight of 426 belonging to the ursene group).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 154–157, March–April, 1981.  相似文献   

20.
The13C kinetic isotope effect fractionation in the decarbonylation of lactic acid (LA) of natural isotopic composition by concentrated phosphpric acids (PA) and by 85% H3PO4 has been studied in the temperature interval of 60–150°C. The values of the13C(1) isotope effects in the decarbonylation of lactic acid in 100% H3PO4, in pyrophosphoric acid and in more concentrated phosphoric acids are intermediate between the values calculated assuming that the C(1)–OH bond is broken in the rate-controllin gstep of dehydration and those calculated for rupture of the carbon-carbon bond in the transition state. In the temperature interval of 90–130°C the experimental13C fractionation factors determined in concentrated PA approach quite closely the13C fractionation corresponding to C(2)–C(1) bond scission. the13C(1) kinetic isotope effects in the decarbonylation of LA in 85% orthophosphoric acid in the temperature range of 110–150°C coincide with the13C isotope effects calculated assuming that the frequency corresponding to the C(1)–OH vibration is lost in the transition state of decarbonylation. A change of the mechanism of decarbonylation of LA in going from concentrated PA medium to 85% H3PO4 has been suggested. A possible secondary18O and a primary18O kinetic isotope effect in decarbonylation of lactic acid in phosphoric acids media have been discussed, too.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号