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 375 毫秒
1.
The total flavonoids have been isolated from the epigeal part ofThermopsis alterniflora andTh. dolichocarpa, and the roots and rhizomes ofVexibia alopecuroides, andRhaponticum carthamoides the compositions of the flavonoids present in each of the total extracts have been determined. It was found that the total flavonoid extracts investigated exhibited different degrees of hypolipidemic activity in relation to normal animals and animals with experimental hyperlipidemias. The total flavonoids fromTh. alterniflora possessed the most pronounced hyperlipidemic action.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (371) 120 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 174–177, March–April, 1999.  相似文献   

2.
Eighteen alkaloids have been isolated from two species ofConvolvulus, ten of which were new. The structures of nine of the latter, including two dimeric bases, have been established. Transitions between them have been effected.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 687–689, September–October, 1986. Original article submitted February 19, 1996.  相似文献   

3.
Summary The flavonoids present in the leaves and flowers ofAlthaea armeniaca Ten., A. cannabina L., A. narbonesis Pourr. andA. broussonetiifolia Iljin were investigated and compared to the flavonoids present in the leaves and flowers ofA. officinalis L. The inliquid chromatography and two-dimensional paper chromatography. The same flavonoids were found in the flowers of all the investigated species while differences could be noted in the flavonoid composition of the leaves. Both the qualitative and quantitative difference was the greatest in the flavonoids of the leaves ofA. cannabina L.  相似文献   

4.
Summary A new HPLC method permitted the separation of 13 triterpene lycosides isolated from differentAstragalus species within 40 min. A water/acetonitrile gradient was used as eluent and 5 μm RP-18 material as stationary phase. By using an evaporative light scattering (ELS) detector, the main saponins ofA. membranaceus could be detected at levels as low as 20.0 μg·mL−1. This method facilitated distinction of differentAstragalus species as well as the analyses of market products containingA. membranaceus. The results showed variations from 0.019 to 0.184% in the total saponin content of the market products.  相似文献   

5.
Detailed chemotaxonomic studies were undertaken to establish the qualitative profile and real amounts of the pharmacologically active isoflavone aglycones genistein, daidzein, formononetin, and biochanin A in aerial parts of thirteen Trifolium L. (clover) species, native to Poland. A newly elaborated micropreparative technique – SPE – on BakerBond octadecyl, cyclohexyl, and phenyl cartridges was used in combination with ultrasound‐assisted extraction for isolation of isoflavone aglycones from hydrolyzed samples. The effectiveness of all three SPE sorbents in the purification of plant extracts was compared and very high recoveries (>96%) were documented for four isoflavones. Classical photodiode‐array and very sensitive fluorescence detection, coupled with reversed‐phase high‐performance liquid chromatography (RP‐HPLC), were employed to obtain the most reliable qualitative and quantitative results. Chemotaxonomic differences combined with flower color variability were demonstrated within thirteen clover species. Concentration levels of particular isoflavones in ten Trifolium species possessing flowers with white, pink, or purple‐red corolla ranged from ∼︁3 to ∼︁3300 μg/g dry weight, while in three yellow flowering clovers (T. aureum, T. dubium, and T. campestre) isoflavone compounds have not been detected at all. RSD values, determined for intra‐ and inter‐day precision of the quantitative results, were not higher than 6.2% and 7.1%, respectively.  相似文献   

6.
Summary The quantitative determination of quercetin and dihydroquercetin in the total flavonoids ofLatrix dahurica has been effected by the use of thin-layer chromatography on Kapron for separating the mixture with subsequent elution of the spots and colorimetry of the eluates obtained. The methanol-dimethylformamide (1:1) system was used as the eluate. It has been found that the flavonoids of the heartwood ofLatrix dahurica contain a predominating amount, 69% of dihydroquercetin, the amount of quercetin being 11%.Khimiya Prirodnykh Soedinenii, Vol. 3, No. 5, pp. 298–301, 1967  相似文献   

7.
Reversed-phase LC on C-18 bonded silica with a methanol–ammonium formate gradient was used to determine the main flavonoids in leaves of four species of the Leguminosae family. The detection modes were diode-array UV absorbance, fluorescence, and (tandem) mass spectrometry. LC–UV was used for a general screening, sub-classification, and the calculation of total flavonoid contents. LC–FLU was included to identify isoflavones on the basis of their native fluorescence. Most structural information regarding aglycons, sugar moieties, and acidic groups was derived from LC–MS in both the full-scan and extracted-ion mode, using negative-ion atmospheric pressure chemical ionization. MS/MS did not provide much additional information, because the same fragments were observed as in full-scan MS.In T. pratense and T. repens, the main constituents were flavonoid glucoside–(di)malonates, while T. dubium and L. corniculatus mainly contained flavonoid (di)glycosides. Satellite sets comprising an aglycon, the glucoside and glucoside–malonates or –acetates, were abundantly present only in T. pratense. Generally speaking, the main aglycons and sugars in the four plant species are surprisingly different. In addition, while the results for T. pratense are similar to those reported in the literature, there is little agreement in the case of the other species. Finally, total flavonoid contents ranged from 50–65 mg/g for L. corniculatus and T. dubium, to 15 mg/g for T. pratense and only 1 mg/g for T. repens.  相似文献   

8.
Micellization ofn-decylamine in aqueous solution leads to substantial decrease in its pK a, and increase in its reactivity in the nucleophilic substitution ofp-nitrophenylic esters of carboxylic acids (up to 70 times compared to ethylamine which forms no micelles). The influence of cetylpyridinium bromide on the acid-base properties ofn-decylamine and its reactivity was investigated. It was found that the reaction withn-decylamine can be accelerated or retarded depending on the hydrophobicity of the esters. The quantitative characteristics of the mieellar catalytic processes were estimated.Translated fromIzvestiya Akademii Nauk Seriya Khimicheskaya, No. 2, pp. 366–370, February, 1996.  相似文献   

9.
The present communication gives the results of an investigation of the carbohydrates isolated from the leaves of eight species ofUngernia. From a single sample were successively extracted the water-soluble polysaccharides, the glucofructans, the pectin substances, and the hemicelluloses. The qualitative and quantitative monosaccharide compositions of the carbohydrates isolated were determined, and the characteristics of the pectin substances are given.Deceased.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 647–650, September–October, 1984.  相似文献   

10.
The chemical compositions of the waxes of the flowers ofRosa gallica L., Jasminum grandiflorum L., andViola odorata L. have been characterized. The waxes of these plants mainly contained hydrocarbons and fatty and cyclic alcohols and their esters with fatty acids. The highest level of free fatty acids (12.4%) was found in theJ. grandiflorum wax. Depending on the plant species, the above-mentioned groups of substances differed in composition and amount, but hydrocarbons predominated.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (371) 120 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 327–333, May–June, 1999.  相似文献   

11.
The chemical composition of the essential oil ofZiziphora clinopodioides has been studied by GLC. A similarity of the qualitative compositions of the terpenoids of the essential oils ofZ. clinopodioides and other species of this genus has been shown.Institute of Phytochemistry, Academy of Sciences of the Republic of Kazakhstan, Karaganda, fax (3212) 51 10 23. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 66–68, January–February, 1999.  相似文献   

12.
Water-soluble polysaccharides have been isolated from two species ofEremurus — E. lactiflorus andE. luteus — with yields of 13.5% and 20.5%, respectively. They contained mainly glucose and mannose in ratios of 1:5 and 1:3.1. The polysaccharides ofE. lactiflorus were separated from a column of DEAE-cellulose. The yield of neutral fraction was 10.3%. Gel filtration of the polysaccharides on Sephadex G-200 showed their polydispersity. Homogeneous fractions were obtained by fractional precipitation with ethanol. They have been characterized with respect to monosaccharide composition, molecular weight, and IR spectra.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 604–608, September–October, 1979.  相似文献   

13.
A method has been developed for the quantitative spectrophotometric determination of the lipopolysaccharides ofE. coli 675. The maximum absorption of the lipopoly-saccharides fromE. coli 675 (259 nm) coincides with the maximum absorption (259 nm) of a number of polysaccharides from other Gram-negative bacteria, which can be used to determine lipopolysaccharides in various media.All-Union Scientific-Research Institute of Pharmacy, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 599–601, September–October, 1979.  相似文献   

14.
The ability of a series of ortho-functionalized phenol derivatives and ofN-(2-hydroximinocyclohexyl)palmitohydroxamic acid to extract Zn2+ ions from aqueous alkali solutions (0.2–4.0 mol L–1) in the presence of trialkylmethylammonium methylsulfate has been investigated. The most active extractants are chelating phenols containing N- and S-coordinating groups and chelates of the pyrocatechol series.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1279–1281, May, 1996.  相似文献   

15.
Analysis of PMR spectra of the dioxane lignins of three species ofAthea, of kenaf, and of the cotton plant has shown that the number of free aromatic protons does not correlate with the number of OCH3 groups, which indicates different degrees of condensation of the dioxane lignins studied. In all the preparations a very small amount of coumarane structures were found. The aliphatic OH groups have been distinguished as primary (-OH) and secondary (-OH) and their quantitative estimation has been carried out from the PMR spectra.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 560–563, July–August, 1980.  相似文献   

16.
FiveBetula species,B. pendula, B. browicziana, B. medwediewii, B. litwinowii, andB. recurvata, were collected from different parts of Turkey. The leaves of these species were hydrodistilled to yield the consequent essential oils. The essential oil compositions were investigated by GC/MS. 14-Hydroxy--caryophyllene was the main constituent in the oil ofB. pendula. 14-Hydroxy-4,5-dihydro--caryophyllene, a new compound, was identified as the main constituent in the oils ofB. browicziana, B. litwinowii, and B. recurvata. In the oil ofB. medwediewii methyl salicylate was the main compound. Various phytopathogenic fungi were studied by the agar tube dilution technique to test the antifungal activities of the essential oils at 400 g/ml concentration. The essential oils showed strong antifungal activity againstCephalosporium aphidicola, Drechslera sorokinianse, Fusarium solani, andRhizoctonia cerealis.Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 126–130, March–April, 2000.  相似文献   

17.
In this study, the fatty acid contents of some Astragalus L. (Fabaceae) species from Turkey were determined by GC and GC-MS techniques. The seed oils of Astragalus sp. (A. echinops Aucher ex. Boiss., A. subrobustos Boriss., A. jodostachys, Boiss. & Buhse., A. falcatus Lam., A. fraxinifolius DC.) contained linolenic (between 23–41.%), linoleic (23–37%), and oleic acids (8–19%) as the major components. Fatty acid composition of the studied Astragalus taxa showed uniform fatty acid patterns. Palmitic and stearic acids were the major saturated fatty acids in the seed oils. The amounts of unsaturated fatty acids were higher than saturated fatty acids. Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 526–528, November–December, 2006.  相似文献   

18.
An evaluation has been mde of the cardiotonic activities of cycloartane methylsteroids isolated from plants of the genusAstragalus and their synthetic analogs. It has been established that the compounds investigated exhibit a positive inotropic effect expressed to different degrees. The mechanism of the realization of the positive inotropic action of cycloartane glycosides differs from that of cardiosteroid drugs.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 510–514, July–August, 1994.  相似文献   

19.
Chemical components from the aerial part of the Kazakhstan population of Artemisia pontica, from which the rarely encountered flavonoids 7-O-methyl- and 4′,7-di-O-methyl-esters of apigenin were isolated for the first time, were identified. The complete chemical composition of the essential oil was established using GC-MS.__________Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 143–145, March–April, 2005.  相似文献   

20.
Four lithium metal precursors (LiNO3, CH3COOLi, LiOH, LiCl) have been used as promoters in Pt–Sn/Al2O3 catalysts to improve activity, selectivity and stability in a modeln-decane dehydrogenation reaction. Acidity, TPR and TPCO measurements have shown that the precursors affect the acid site distribution in the support, modify the reducibility and dispersity of Pt–Sn active species, coke lay-over patterns, stability and also selectivity for formation of monoolefins in the dehydrogenation ofn-decane.  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