首页 | 官方网站   微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 265 毫秒
1.
2-N-Oleoylamino-octadecane-1,3-diol is a new synthetic ceramide. The process enables a four-step preparation of 2-amino-octadecane-1,3-diol (D,L-erythro/threo) and a five-step synthesis of 2-N-oleoylamino-octadecane-1,3-diol (D,L-erythro/threo). The latter compound is related to ceramide 2 according to the classification of Downing. This route of synthesis is rapid, reproducible and uses low-cost starting materials. The new ceramide was analysed as follows: 1H, 13C, 15N NMR spectra afforded an unambiguous characterization of the structure; additionally, these three methods identified the threo and erythro isomers. 1H and 13C NMR permitted the measurement of the threo/erythro ratio (26.6/73.4 and 25.5/74.5, respectively). Chemical ionization mass spectrometry confirmed the expected mass of the pseudo-molecular ion (m/z= 566.5: [M + H]+) as well as the presence of different chain lengths other than the oleic moiety due to the fatty acid composition of the technical grade oleic acid used for the synthesis. Capillary gas chromatography measured the threo/erythro ratio (23.5/76.5) which agrees with the 1H and 13C NMR data. Moreover, this method afforded the relative distribution of the different N-acylated chains. The properties of the new synthetic ceramide for the treatment of skin and hair were mainly assessed by two in vitro methods. The first measured the flux of water through lipid-extracted stratum corneum. The described ceramide showed high efficacy in decreasing water loss. The second recorded the friction coefficient of different types of hair: virgin, permanent-waved, and bleached. Treatment by the ceramide led to a strong decrease in this coefficient. This was particularly observed on unrinsed hair. These findings suggest two potential fields of application and beneficial contribution for the new ceramide: repairing the barrier to transepidermal water loss, and improving the surface properties of hair. Synthèse du 2-N-oleoylamino-octadécane-1,3-diol: nouveau céramide à haut potentiel dans le soin de la peau et du cheveu.  相似文献   

2.
BACKGROUND: Both qualitative and quantitative analyses of the major phenolic compounds in barley and flaxseed hulls were conducted using reverse phase high‐performance liquid chromatography coupled with photodiode array detection and quadrupole time‐of‐flight mass spectrometry. RESULTS: Ferulic acid, p‐coumaric acid, vanillic acid and vanillin were identified and quantified in four barley hull samples. Four ferulate dehydrodimers were also detected. The phenolic compounds of flaxseed hull were distinct from those of barley hull. Three flaxseed hull samples varied significantly (P < 0.05) in their contents of secoisolariciresinol diglucoside (16.38–33.92 g kg?1), coumaric acid glucoside (35.68–49.22 g kg?1) and ferulic acid glucoside (5.07–15.23 g kg?1). The phytochemical profiles of co‐extracts featured the major phenolic compounds from both barley and flaxseed hulls. The total phenolic content and 2,2‐diphenyl‐1‐picrylhydrazyl radical‐scavenging capacity varied significantly (P < 0.05) among different varieties of flaxseed and barley hulls. CONCLUSION: As agricultural by‐products, barley and flaxseed hulls may be utilised as potential sources of functional food ingredients through extraction and concentration of the phytochemicals identified above. Copyright © 2012 Society of Chemical Industry  相似文献   

3.
An antioxidative compound with effective exercise-enhancing potential was isolated from the ethanolic extract of Pseudosasa japonica leaves. The ethanolic extract was partitioned in the order of hexane, chloroform, ethyl acetate, and water. Of the 4 fractions, the ethyl acetate-fraction (PJE-E) showed profound scavenging activity on superoxide anion- and ABTs cation radicals. Thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) were conducted to isolate a compound with antioxidative activity on exercise endurance capacity from the PJE-E. The structure of the resulting compound was identified as ferulic acid by 1H/13C nuclear magnetic resonance (NMR). This ferulic acid was orally administered to mice for 18 days and its effect on exercise endurance capacity was investigated using an adjustablecurrent water pool. Compared to the control group, a 1.8 fold increase in swimming time was observed in the ferulic acid-administered mice. Results indicate that ferulic acid from P. japonica leaves might contribute to the potent exercise-enhancing effect.  相似文献   

4.
Chinese olive (Canarium album L.), one native and well-known tropical fruit tree in the southeast of China, contain a large amount of phenolics and possess great pharmacological activities. In this study, phenolics were extracted from Chinese olive fruit using 80% (v/v) aqueous acetone, and seven phenolic compounds were isolated and purified by Polyamide column and Toyopearl HW-40 column chromatography from crude extracts. Their structures were elucidated by high performance liquid chromatography coupled to diode array detection and electrospray ionization mass spectrometry (HPLC-DAD-ESI-MS), and where possible by 1H NMR and 13C NMR spectrometry. Except gallic acid and hyperin, five phenolic compounds including methyl gallate, ethyl gallate, corilagin, kaempferol-3-glucoside and amentoflavone were first identified in Chinese olive.  相似文献   

5.
BACKGROUND: Cross‐links between plant cell wall polymers negatively impact forage digestibility. Hydroxycinnamates and their oligomers act as cross‐links between polysaccharides and/or polysaccharides and lignin. Higher ferulate oligomers such as dehydrotrimers were identified in cereal grains but not in vegetative organs of grasses. The aim of this study was to characterize ester‐linked hydroxycinnamate oligomers from corn stover with special emphasis on ferulate dehydrotrimers. RESULTS: With the exception of the 4‐O‐5‐dehydrodiferulic acid all known ferulate dehydrodimers, including the recently described 8‐8(tetrahydrofuran) dimer, were identified in the alkaline hydrolyzate of corn stover after chromatographic fractionation. Next to dehydrodimers, 18 cyclobutane dimers made up of ferulic acid and/or p‐coumaric acid were identified by GC‐MS of the dimeric size exclusion chromatography fraction. Ferulate dehydrotrimers were isolated by using multiple chromatographic procedures and identified by UV spectroscopy, MS and NMR. Four trimers were unambiguously identified as 5‐5/8‐O‐4‐, 8‐O‐4/8‐O‐4‐, 8‐8(aryltetralin)/8‐O‐4‐, and 8‐O‐4/8‐5‐dehydrotriferulic acids, a fifth tentatively as 8‐5/5‐5‐dehydrotriferulic acid. CONCLUSION: The formation of ferulate dehydrotrimers is not limited to reproductive organs of grasses but also contribute to network formation in the cell walls of vegetative organs. Although radically coupled hydroxycinnamate dimers and oligomers were in the focus of researchers over the last decade, the earlier described cyclobutane dimers significantly contribute to cell wall cross‐linking. Copyright © 2010 Society of Chemical Industry  相似文献   

6.
Anthocyanin extracts are increasingly used as food colorants. So far, anthocyanins have not been broadly used in foods and beverages, since they are not as stable as synthetic dyes. Copigmentation between anthocyanins and copigments is the main colour‐stabilizing mechanism. The process of copigmentation between isolated acylated anthocyanin and rutin, QSA or baicalin has been observed using UV–vis spectrophotometry. The thermodynamic parameters were correlated to the structure and position of the substituents in the interacting molecules. The acylated anthocyanin was isolated from cultivars of Scutellaria baicalensis Georgi flowers and purified by column chromatography by our own method and has been identified by 1H‐/13C‐NMR spectroscopy and electrospray mass spectrometry as delphinidin‐3‐O‐(6‐O‐malonyl)‐β‐D ‐glucopyranosyl‐5‐O‐β‐D ‐glucopyranoside. Copyright © 2004 Society of Chemical Industry  相似文献   

7.
Aqueous extractions (at 25 °C) of flours from six Greek wheat cultivars that differed in their bread-making quality, followed by porcine pancreas α-amylase digestion to remove starch contaminants and precipitation with ammonium sulphate (saturation at 95%), yielded arabinoxylan isolates with notable differences in molecular weight, ranging from 146,500 to 397,000, and in arabinose-to-xylose ratios (Ara/Xyl, varying between 0.57 and 0.71). The arabinoxylan isolates contained only small amounts of proteins and were relatively free of other polysaccharide contaminants. Generally a very high ratio of trans to cis-ferulic acid content was detected for all samples. The genotype also had an impact on the molecular characteristics of these polysaccharides. 1H NMR spectroscopy revealed variations in the un-substituted (61.1–67.9%) and di- (19.4–28.1%) and mono-substituted xylose residues (10.0–16.6%). Using 2D NMR spectroscopy, it was feasible to identify the spin sequence of individual monosaccharide residues and elucidate their structure, despite the extensive overlapping of 1H and 13C resonances. Differences in the physicochemical properties of the arabinoxylans, such as the critical concentration values (c∗ and c∗∗), viscosity, shear-thinning behaviour, as well as the gelling ability, could not be fully explained by differences in molecular size and structure of the isolated polysaccharides.  相似文献   

8.
The antioxidant activity and phenolic compound profiles of six fractions (I–VI) obtained from sunflower seed extract were studied. HPLC–MS(ESI) analysis was applied for quantitative and qualitative determination of phenolic compounds of the fractions. The antioxidant activity of the fractions was studied in terms of their ability to scavenge DPPH· and ABTS·+ and to reduce Fe3+/ferricyanide complex to the ferrous form and was expressed as EC50, TEAC and reducing power values, respectively. The results of all antioxidant activity tests showed good correlations among each other and with the phenolic contents for the individual fractions. The fractions IV–VI were characterized by high antioxidant activity. 5-O-Caffeoylquinic acid was a predominant compound of fractions IV and V, while dicaffeoylquinic acid isomers and caffeoyl-dimethoxycinnamoylquinic acid isomers accounted for 76.6 % of phenolic compounds of fraction VI. Ferulic acid, p-coumaroylquinic acid isomers, ferulic acid dehydrotrimer isomers and some quercetin derivatives were also identified. The highest content of those compounds was noted in fraction III.  相似文献   

9.
The gum from Hymenaea courbaril (Caesalpiniaceae) produced gum at seed level. The gum is soluble in water, dextrorotatory and less viscous than the gum from Cyamopsis tetragonolobus (guar gum). The polysaccharide, isolated from this gum, contains galactose, glucose, xylose and arabinose. The preparation of degraded products by acid hydrolysis and Smith-degradation process led to obtain degraded gums A and B, and the polysaccharides I and II. Chemical methods in combination with 1D NMR (1H, 13C, DEPT-135) and 2D NMR (COSY, HMQC and HMBC) were applied. The backbone is a xylogalactan; β-d-galactose and β-d-xylose residues are 4-O- and 2-O-linked, respectively. The branches are constituted by xylose, arabinose and galactose. It was also observed 4,6-di-O-substituted galactose residues. This work shows interesting structural features of the polysaccharide isolated from H. courbaril gum.  相似文献   

10.
In recent years, researches on the isolation and preparation of monomeric anthocyanins have intensified because of the requirements of quantitative and structure–bioactivity relationship analyses. However, simple and effective methods about the scale of monomeric anthocyanins from the natural purple sweet potato powder are rarely reported. In this study, high molecular weight acylated monomeric anthocyanins were isolated from purple sweet potato (Ipomoea batatas L. cultivar Eshu No. 8) via the combination of column chromatography and semi‐preparative HPLC technology and identified mainly by ultra‐high‐performance liquid chromatography quadrupole time‐of‐flight tandem mass spectrometry/mass spectrometry (UPLC‐QTOF‐MS/MS) and 1H and 13C nuclear magnetic resonance (NMR). Two major acylated anthocyanins were unambiguously determined as peonidin 3‐O‐(6‐O‐(E)‐caffeoyl‐(2‐O‐(6‐O‐p‐hydroxybenzoyl)‐β‐D‐glucopyranosyl)‐β‐D‐glucopyranoside)‐5‐O‐(β‐D‐glucopyranoside) and peonidin 3‐O‐(6‐O‐(E)‐caffeoyl‐(2‐O‐(6‐O‐(E)‐feruloyl)‐β‐D‐ glucopyranosyl)‐β‐D‐glucopyranoside)‐5‐O‐(β‐D‐glucopyranoside). The results of this study may help promote the purification of high molecular weight acylated anthocyanins from purple sweet potato as well as from other plant materials in nature.  相似文献   

11.
Using the more recently available techniques such as methylation–GC–MS, 1D (1H, 13C) and 2D (COSY, TOCSY, HMQC and HMBC) NMR spectral analysis, we have revisited the classical structure of gum arabic (Acacia senegal). Methylation and GC–MS analysis confirmed that gum arabic (A. senegal) is a highly branched polysaccharide with the backbone composed of 1,3-linked galactopyransyl (Galp) residues substituted at O-2, O-6 or O-4 positions. The terminal sugar residues are 59.5% of the total sugars. The residues of →2,3,6-β-d-Galp1→, →3,4-Galp1→, →3,4,6-Galp1→ and substitutions at O-2 and O-4 position were not identified in previous studies.  相似文献   

12.
Cold aqueous extraction of basidiocarps (fruiting bodies) of the edible mushroom Lentinus edodes (shiitake) gave rise to a heteropolysaccharide, whose chemical structure, antinociceptive and anti-inflammatory properties were determined. Its chemical structure was based on monosaccharide composition, methylation analysis, and NMR spectroscopy (1H, 13C, HSQC, HSQC-TOCSY, HSQC-NOESY, and coupled HMQC). It was found to be a fucomannogalactan with a main chain of (1 → 6)-linked α-d-galactopyranosyl units, partially substituted at O-2 by single-unit β-d-Manp or α-l-Fucp side chains. The polysaccharide produced a marked and dose-related effect when assessed against acetic acid-induced visceral nociception. Prevention of peritoneal capillary permeability and leukocyte infiltration caused by the acetic acid was similar in potency and effectiveness.  相似文献   

13.
BACKGROUND: To contribute towards understanding the relationship of structure and bioactivity, a protein‐bound acidic polysaccharide named TPC3‐1 was isolated and purified from low‐grade green tea (Camellia sinensis L.). The homogeneity and weight average molecular weight of TPC3‐1 was determined by agarose gel electrophoresis and high‐performance gel permeation chromatography. The monosaccharide and amino acid composition of TPC3‐1 were analysed by gas chromatography and an amino acid analyser. The molecular structure of TPC3‐1 was characterised by Fourier transform infrared spectroscopy, 13C nuclear magnetic resonance spectroscopy and atomic force microscopy. RESULTS: Based on the data obtained, the average peak molecular weight of TPC3‐1 was about 120 kDa. TPC3‐1 was composed of L ‐arabinose, D ‐ribose, D ‐xylose, D ‐glucose and D ‐galactose with a molar ratio of 4.9:2.2:3.1:1.8:1.0. Fifteen amino acids were identified as components of the polymer. The TPC3‐1 molecule was found to have an anomeric carbon sign of both α and β configurations and high‐branched chains. The network structure of TPC3‐1 was observed. CONCLUSION: The tea polysaccharide TPC3‐1 was an acid protein‐bound polysaccharide with an image of network structure. The results presented here will facilitate further study of the relationship between the chemical structure and biological role of tea polysaccharide. Copyright © 2008 Society of Chemical Industry  相似文献   

14.
A novel pigment, named gardecin, has been isolated from gardenia fruits, together with another five known crocins. The pigment, which possessed a structure which is unique among crocins, was characterised using spectrometric techniques, particularly 1D and 2D NMR. The NMR assignments were based on data from 1H NMR, 13C NMR, DEPT, 1H–1H COSY, NOESY, HMQC and HMBC measurements. The five known crocins were identified on the basis of MS, UV/visible and 1D NMR data. Chemical stability and antioxidant ability of gardecin in comparison with the other five crocins were studied. The stronger DPPH free radical-scavenging ability of gardecin compared, with the other crocins, was observed. Kinetic studies have shown that all crocins were unstable under various conditions, but surprisingly gardecin was fairly stable.  相似文献   

15.
The polar components of Annona crassiflora pulp, peel and seeds ethanolic extracts were investigated by direct infusion electrospray ionization mass spectrometry (ESI-MS) both in the negative ion mode. Characteristic ESI mass spectra with many diagnostic ions were obtained for the extracts, serving for fast and reliable information. The technique provided information of component structures revealing the presence of important bioactive components widely reported as potent antioxidants such as ascorbic acid, caffeic acid, quinic acid, ferulic acid, xanthoxylin, rutin, caffeoyltartaric acid, caffeoyl glucose and [quercetin+hexose+pentose−H]−1 This is the first report on the composition by ESI-MS of araticum peel and seed ethanolic extracts demonstrating excellent antioxidant activity.  相似文献   

16.
Metabolite profiling and biological activity are reported from organic and aqueous extracts of the fruit from the desert palm Hyphaene thebaica. Phenolics and oxylipids profiles were determined using UPLC‐PDA‐TOF (ultra performance‐photodiode array‐time of flight) high‐resolution mass spectrometry in order to obtain the molecular formula and exact mass Under optimized conditions, 17 compounds were simultaneously identified and quantified including 2 cinnamic acid derivatives, 5 flavonoids, 6 fatty acids, 2 sphingolipids, a lignan, and a stilbene. Sugars composition in the fruit was characterized and quantified by 1H‐NMR (nuclear magnetic resonance) with sucrose detected as the major component in fruit at a level of 219 mg/g. Fruit organic extracts anti‐inflammatory potential was assessed in vitro by cyclooxygenase‐1 enzyme inhibition.  相似文献   

17.
A novel method for purifying gingerols from ginger was developed using a high-speed counter-current chromatography (HSCCC). The two-phase solvent system such as light petroleum (bp 60–90 °C)–ethyl acetate–methanol–water (5:5:6.5:3.5, v/v/v/v) was applied to the separation and purification of 6-, 8- and 10-gingerol from a crude extract of ginger. The experiment yielded 30.2 mg of 6-gingerol, 40.5 mg of 8-gingerol, 50.5 mg of 10-gingerol from 200 mg of crude extract in one-step separation. And the purity of these compounds was 99.9%, 99.9% and 99.2%, respectively, as determined by high-performance liquid chromatography (HPLC). Their structures were identified by gas chromatography–mass spectrometry (GC/MS) and 1H, 13C nuclear magnetic resonance (NMR).  相似文献   

18.
The regional origin of Chinese wines was investigated using two important complementary techniques, site‐specific natural isotopic fractionation nuclear magnetic resonance (SNIF‐NMR) and isotope ratio mass spectrometry (IRMS). Twenty samples from five different grape varieties were collected from north Xinjiang in 2009, along with 100 wine samples from five different regions during 2010–2013. The (D/H)I and (D/H)II in wine ethanol ranged from 95.10 to 102.86 ppm and from 115.99 to 126.39 ppm using SNIF‐NMR, respectively. The 13C/12C of wine ethanol and 18O/16O of wine water were detected using IRMS. The δ13C value (?23.36‰) in coastal regions was higher than that in continental regions (?27.75‰). The temperature is the key for δ13C value. The δ18O ranged from ?1.94 to 4.57‰. The δ18O values were only positive in north Xinjiang which had the arid climate and strong sunshine. No difference was found for isotope ratios for wines made from five different grape varieties in north Xinjiang. All data evaluated by principal component analysis and linear discriminant analysis showed that the best method to distinguish the regional wine origin correctly is a combination of (D/H)I, (D/H)II, R, δ13C and δ18O. Therefore, natural multi‐elemental isotope ratios are effective in contributing to wine quality control in the Chinese market.  相似文献   

19.
Noni (Morinda citrifolia L.) is an edible and medicinal plant distributed in Hainan, China. The antibacterial activities of the extracts of water (WE), petroleum ether (PEE), ethyl acetate (EAE), chloroform (CE), and n‐butanol (BE) were assayed by the disk diffusion method. The results showed that the extracts from Noni leaves possessed antibacterial effects against Bacillus subtilis, Escherichia coli, Proteus vulgaris, and Staphylococcus aureus. Among 5 different extracts, the BE produced the best antibacterial activity. The samples were first extracted by ethanol, and the primary compounds in the BE fraction of ethanol extract was further isolated and identified. Six phenolic compounds, including 5, 15‐dimethylmorindol, ferulic acid, p‐hydroxycinamic acid, methyl 4‐hydroxybenzoate, methyl ferulate, and methyl 4‐hydroxycinnamate, were identifiedby NMR. The results indicated that the phenolic compounds might significantly contribute to antibacterial activities of Noni leaves.  相似文献   

20.
Ferulic acid (4‐hydroxy‐3‐methoxycinnamic acid), predominantly in ester form in arabinoxylan chains, is the main phenolic acid present in barley and malt. Only about 1% of the total ferulic acid in barley is present in the free form. A number of previous works concerned the contents of free and esterified ferulic acid in a broad range of popular beers, but there is little information about the possible composition of feruloylated oligosaccharides in beers. The aim of this preliminary work was to purify the feruloylated oligosaccharides from lager beers (by the means of preparative chromatography) followed by composition elucidation using TLC, HPLC with RI or UV detection and 1H‐NMR. Indeed, the qualitative analyses of isolated fractions from beer revealed that the fractions contained ferulic acid in the ester form (as proven after mild alkaline hydrolysis). It was also shown that molecular masses of oligosaccharides present in the purified beer fractions were similar to the masses of arabinose and xylooligosaccharides in the range of xylose to xylohexaose. Although a number of purified beer samples contained oligosaccharides of higher molecular masses, these were not further characterized. Taking under consideration the presented results, it can be concluded that beer can be a good source of feruloylated oligosaccharides, significant in the context of human health benefits.  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-23

京公网安备 11010802026262号