Spectroscopic methods
-
Study on the chemical constituents of methanol extract from leaves of Moringa oleifera Lam. (Moringaceae) has resulted in the isolation of four compounds: Vitexin, isoquercitrin, tricosanol and tetradecanoic acid. Their structures were determined by spectroscopic methods.
5p tamynhan9 02-12-2020 25 2 Download
-
Molecular crystals are characterized by strong intramolecular forces and much weaker intermolecular forces. High-pressure spectroscopic studies provide useful data for refining the various model potentials which are used to predict of the physical properties of such systems as well as for the formation of various crystalline phases.
7p tamynhan8 04-11-2020 16 2 Download
-
Investigation on the chemical constituents of ethyl acetate extract from leaves of Taxus wallichiana Zucc. (Taxaceae), collected in Ha Giang province, has resulted in the isolation of three metabolites for the first time: sciadopitysin (1), β-sitosterol (2), and isoquercitrin (3). Their structures were determined by spectroscopic methods.
6p koxih_kothogmih5 04-09-2020 25 2 Download
-
Three natural compounds including betulin (1), betulinic acid (2) and lupeolactone (3) were isolated from the dichloromethane extract of Helicteres hirsuta Lour. for the first time. Their structures have been elucidated by modern spectroscopic methods as IR, 1H-NMR, 13C-NMR, DEPT, HSQC, HMBC, MS and by comparison with those of previously reported data.
8p slimzslimz 08-12-2019 37 0 Download
-
From the ethyl acetate extract of the rhizomes from Belamcanda chinensis (Iridaceae) five compounds irisflorentin (1), tectorigenin (2), iristectorigenin A (3), irigenin (4), and acetovanillone(5) were isolated. Their structures were elucidated by spectroscopic methods. This is first report of 5 from B. chinensis.
5p giesumanh 13-11-2018 32 1 Download
-
Melodinus oblongus is one species still non-investigated. From the stem barks of this plant 18 indole alkaloids have been isolated and characterized by spectroscopic methods.
7p uocvong05 09-10-2015 43 2 Download
-
Two limonoids limonin and limonexic acid have been isolated from the dichloromethane extract of leaves of Tetradium trichotomum, besides three indolopyridoquinazoline alkaloids, rutaecarpine, evodiamine, N13 -methyl rutaecarpine and -sitosterol. The structures of these compounds were determined by spectroscopic methods.
4p uocvong05 09-10-2015 33 2 Download
-
Maytensifolin B, –amyrin and clerolsterol were isolated from stem bark of Arnicratea cambodiana (Pierre) N. Hall. for the first time. Their structures were elucidated by means of spectroscopic methods and comparison with reported data.
4p uocvong04 24-09-2015 30 4 Download
-
From the alkaloid fraction of Aconitum carmichaeli roots, growing in Sa Pa district, Lao Cai province, two diterpene alkaloids and -sitosterol glucoside were isolated. The structure of both alkaloids have been determined as karacoline and benzoylmesaconine by using MS and NMR spectroscopic methods.
6p uocvong04 24-09-2015 51 3 Download
-
Starting from 3-hydroxy-lup-20(29)-en-23,28-dioic acid, which is isolated with high yield from the plant Schefflera octophylla (Lour.) Harms (Araliaceae), a series of amide esters and amide acids with amino acids have been synthesized. All the synthesized compounds are new. Their structures were determined by IR, MS and NMR spectroscopic methods.
5p uocvong04 24-09-2015 52 2 Download
-
The total alkaloid and non-alkaloid fractions were extracted from the leave of Ficus hispida L., colleted in Nghe An province. Its cytotoxicity in vitro against three cancer cell lines has been investigated. The cytotocic activities of total alkaloids against these cancer cell lines are very strong than that of non-alkaloid fraction. From non-alkaloid part, betulinic acid was isolated and its structure was elucidated by spectroscopic methods.
5p uocvong04 24-09-2015 48 4 Download
-
Five flavonoids along with -sitosterol were isolated from the leaves of Polygonum hydropiper L. (Polygonaceae). Four flavonoids were identified as quercetin, quercetin-3-O- -L- rhamnoside (quercitrin), quercetin-3-sulphate and (+)-catechin. Their structures were established on the basis of chemical evidence and spectroscopic techniques, including 2D NMR methods.
5p uocvong04 24-09-2015 57 2 Download
-
Starting from 3-hydroxy-lup-20(29)-ene-23,28-dioic acid, isolated with high yield from the plant Schefflera octophylla (Lour.) Harms (Araliaceae), a series of amide esters and amide acids have been synthetized. All the synthetized compounds are new. Their structures were determined by the IR, MS and NMR spectroscopic method.
5p uocvong04 24-09-2015 52 3 Download
-
Angelica sinensis (OLiv.) Diels ("Danggui") belongs to the family Umbelliferae. Its rhizomes are reputed to have marked restorative, antianaemic and haemagogic properties. From ethyl acetate and butanol extracts of rhizomes of this plant 8 nitrogen-containing compounds (1-8) have been isolated. Their structures were elucidated by means of MS and NMR spectroscopic methods as 5-oxo-proline, 5-oxo-prolin-ethylester, nicotinamide, tryptophane, perlolidine, 1,2,3,4-tetrahydro-1-methyl- -carboline-3-carboxylic acide, adenosine and uridine.
6p uocvong04 24-09-2015 49 3 Download
-
A flavonol glycoside, kaempferol 3-O- -sambubioside (1) was isolated in a study on the polar constituents of the buds of Rhodomyrtus tomentosa Ait. Hassk. (Myrtaceae). Its structure was determined by spectroscopic methods.
3p uocvong04 24-09-2015 34 4 Download
-
The rhizome of Angelica sinensis (Oliv.) Diels (Umbelliferae) is one of the most commonly used traditional drugs in China, indicated against anemia, menstrual disorders, amenorroehea and rheumatism. From the ethyl acetate extract of the roots of A. sinensis a stilbene, ferulic acid, coniferylferulate and decorticate have been isolated. Their structures were identified by MS and NMR spectroscopic methods.
5p uocvong04 24-09-2015 71 3 Download
-
The rhizome of Angelica sinensis (Oliv.) Diels (Umbelliferae) is known as "Danggui" in China, has been used widely in traditional Chinese medicine to treat irregular menstruation, anaemia, headache, hypertension, chronic asthma and rheumatism. From the ethyl acetate extract of its roots four phthalides have been isolated. Their structures were identified by MS and NMR spectroscopic methods to be (Z)-3-butylidenphthalide, senkyunolide H, senkyunolide I and dihydroxyligustilide.
4p uocvong04 24-09-2015 55 5 Download
-
The chemical structure of lipid A from the lipopolysaccha-ride of the mushroom-associated bacterium Pseudomonas reactans,a pathogen of cultivated mushroom, was elucida-ted by compositional analysis and spectroscopic methods (MALDI-TOF and two-dimensional NMR). The sugar backbone was composed of theb-(1¢fi6)-linkedD-gluco-samine disaccharide 1-phosphate.
8p research12 29-04-2013 39 2 Download
-
The major cellulase secreted by the filamentous fungus Trichoderma reeseiis cellobiohydrolase Cel7A. Its three-dimensional structure has been solved and various mutant enzymes produced. In order to study the potential use of T. reeseiCel7A in the alkaline pHrange, the thermal sta-bilityofCel7Awas studiedas a functionof pHwith thewild-type and two mutant enzymes using different spectroscopic methods. Tryptophan fluorescence and CD measurements of the wild-type enzyme show an optimal thermostability between pH3.5–5.
8p tumor12 20-04-2013 37 3 Download
-
The reactions of a few representative gold(III) complexes – [Au(ethylenediamine)2 ]Cl3 , [Au(diethylentriamine)Cl]Cl2 , [Au(1,4,8,11-tetraazacyclotetradecane)](ClO4 )2Cl, [Au(2,2¢, 2¢-terpyridine)Cl]Cl2,[Au(2,2¢-bipyridine)(OH)2][PF6]and the organometallic compound [Au(6-(1,1-dimethylbenzyl)-2,2¢-bipyridine-H)(OH)][PF6] – with BSA were investigated by the joint use of various spectroscopic methods and separation techniques.
7p fptmusic 12-04-2013 36 2 Download