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1.
High-performance thin layer chromatography (HPTLC) method for the separation and quantitative determination of ten markers (catechins, flavonoids, and phenolics) in different extracts of green tea and guava leaf has been developed and the antioxidant activity profiles of the two plant extracts have been determined. Ten marker compounds have been resolved using silica gel 60 F(254) plates, toluene/acetone/formic acid (5:4:1 v/v/v) for markers 1-6, and toluene/ethyl acetate/formic acid/methanol (3:3:0.8:0.2 v/v/v/v) for markers 7-10 as the mobile phases. The high-performance thin layer chromatography densitometry was performed at wavelengths of 282 and 285 nm for the markers 1-6 and 7-10, respectively. Potent antioxidant activity and the presence of phenolics and flavan-3-ols has been observed for the guava leaf extracts suggestive of its use as an alternate economical source of antioxidants over green tea--the well-established food additive/nutraceutical agent.  相似文献   

2.
The kinetic resolution of racemic 1-phenylethanol with ethyl acetate was investigated in a down-flow fixed-bed reactor operated in a continuous mode mainly at the molar ratio of 1: 3 in 400 mL toluene at 70°C. The catalytic activity of the immobilized lipase was studied by: (i) changing the flow rates, (ii) utilizing different substrate concentrations, (iii) applying step changes using ethyl acetate, ethyl benzene, acetic acid, acetophenone etc., (iv) investigating the inhibitory effect of either the desired or the stoichiometric products (R)-1-phenylethyl acetate and ethanol, respectively), (v) elucidating the effect of water on the activity and stability of the immobilized lipase. The residence time distribution and the reactor hydrodynamics were also discussed along with kinetic modelling. The results were linked to the one-pot reactions.  相似文献   

3.
Henophyton deserti was characterized in respect to its chemical composition, antioxidant potential and antimicrobial activity. Fourteen compounds were identified by LC/MS, GC/MS, and GC in leaf and seed extracts. Total flavonoids ranged between 45.66 and 181.2 mg QE g?1 and 2.03 and 38.95 mg QE g?1 dry weight (dw) in leaf and seed polar extracts, respectively. Rutin, Kaempferol 3-rutinoside, Diosmetin 7-O-Glucoside, and Acacetin 7-O-Glucoside flavonoids were tentatively identified in this plant. The profile of seed fatty acids revealed oleic acid (C18:1, 27%), linoleic acid (C18:2, 12%) and linolenic acid (C18:3, 17%). The highest antioxidant activities of 85.2% and 67.5% were obtained with methanol and ethyl acetate leaf extracts. All H. deserti extracts were active against at least one of the tested bacteria, leaf ethyl acetate extract showed the lowest MIC of 0.156 mg ml?1. Only seed ethyl acetate extract showed antifungal activity with a MIC of 2.5 mg ml?1.  相似文献   

4.
Erythrocentaurin is a relatively simple natural product present among the members of Gentianaceae. A preparative method for the isolation of erythrocentaurin from the ethyl acetate fraction of Enicostemma littorale using medium‐pressure liquid chromatography has been reported. The method consisted of a simple step gradient from 10 to 20% ethyl acetate in n‐hexane. Using a 70 × 460 mm Si60 column, this method is capable of processing 20 g of material in <3 h (purity ≈ 97%). The recovery of erythrocentaurin was 87.77%. Estimation of erythrocentaurin in extracts and fractions based on high‐pressure thin‐layer chromatography was carried out on silica gel 60 F254 plates with toluene/ethyl acetate/formic acid (80:18:2 v/v/v) as the mobile phase. The densitometric analysis was performed at 230 nm. A well‐separated compact band of erythrocentaurin appeared at Rf 0.54 ± 0.04. The analytical method showed good linearity in the concentration range of 200–1500 ng/band with a correlation coefficient of 0.99417. The limits of detection and quantification were found to be ≈60 and ≈180 ng/band, respectively. Erythrocentaurin exhibited a concentration‐dependent α‐amylase inhibition (IC50 1.67 ± 0.28 mg/mL). The outcome of the study should be considered for pharmacokinetic and biotransformation studies involving E. littorale.  相似文献   

5.
ABSTRACT

The aim of this study was to provide the first from-start-to-end thin-layer chromatographic method of fingerprinting the Cistus incanus L. raw herbal material, with a purpose to further use it for rapid screening, authentication, and quality control of the traded C. incanus L. herbs. To this effect, 12 different C. incanus L. samples purchased as herbal teas from a local market were extracted by means of the accelerated solvent extraction (ASE) with chemometrically optimized solvent extraction mixture and temperature (methanol–water, 27:73, v/v; 130°C), to derive the polar fraction from the plant samples. Then, the extracts were developed in two thin-layer chromatographic systems, both using the commercially precoated silica gel 60 chromatographic plates, yet two different mobile phases (mobile phase 1, ethyl acetate–formic acid–acetic acid–water, 100:11:11:13, v/v/v/v, and mobile phase 2, ethyl acetate–dichloromethane–formic acid–acetic acid–water, 100:10:10:10:11, v/v/v/v/v). The chromatograms were densitometrically scanned in the reflectance mode at the wavelength λ?=?366?nm to obtain fingerprints of the extracts derived from individual C. incanus L. samples. Mobile phase 2 performed slightly better, because with its use, the maximum number of 11 peaks could be seen in the respective fingerprints, whereas with mobile phase 1, the maximum number of 10 peaks only. Then an antioxidant potential of the investigated herbal extracts was assessed, making use of mobile phase 2 and the 0.20% methanol solution of 2,2-diphenyl picrylhydrazyl as a visualizing reagent. The resulting chromatograms were densitometrically scanned in the extinction mode at the wavelength λ?=?550?nm to obtain biological fingerprints of the extracts. Finally, chromatographic and biological fingerprints underwent a semiquantitative evaluation in terms of the contents of the extracted polar fraction and an overall antioxidant potential of the individual plant species.  相似文献   

6.
A simple and rapid high-performance thin-layer chromatographic method for quantification of gallic acid and ellagic acid in dried fruits of Terminalia chebula, Phyllanthus emblica, and Quercus infectoria has been developed. The chromatographic development was carried out on precoated silica gel 60 F254 plates in a mixture of toluene:ethyl acetate:chloroform:formic acid (4:8:1:3 v/v/v/v). The plate was scanned densitometrically at a wavelength of 280 nm. The retention factor value of gallic acid and ellagic acid was found to be 0.63 ± 0.2 and 0.53 ± 0.1, respectively. The developed method was validated in terms of linearity, precision, accuracy, sensitivity, robustness, specificity and stability as per the international conference of harmonization guidelines. The method showed good linear relationship over a range of 100–600 ng/band (gallic acid) and 100–500 ng/band (ellagic acid) with a regression coefficient (r2) of 0.997 (gallic acid) and 0.996 (ellagic acid). The method showed high accuracy (99.65%–100.85%). The percentage relative standard deviation of intra-day and inter-day precision studies was not more than 2%. The method is highly robust and has displayed high specificity. The developed method is new, simple, and accurate and can be successfully employed in routine analysis of raw materials and formulations containing gallic acid and ellagic acid.  相似文献   

7.
The essential oil from the aerial parts of Nephrolepis exaltata and Nephrolepis cordifolia obtained by hydro-distillation were analyzed by gas chromatography/ mass spectrometry. The essential oils exhibited potential antibacterial and antifungal activities against a majority of the selected microorganisms. NEA oil showed promising cytotoxicity in breast, colon and lung carcinoma cells. The results presented indicate that NEA oil could be useful alternative for the treatment of dermatophytosis.

Comparative investigation of hydro-distilled volatile constituents from aerial parts (A) of Nephrolepis exaltata (NE) and Nephrolepis cordifolia (NC) (Family Nephrolepidaceae) was carried out. Gas chromatography/mass spectrometry revealed that oils differ in composition and percentages of components. Oxygenated compounds were dominant in NEA and NCA. 2,4-Hexadien-1-ol (16.1%), nonanal (14.4%), β-Ionone (6.7%) and thymol (2.7%) were predominant in NEA. β-Ionone (8.0%), eugenol (7.2%) and anethol (4.6%) were the main constituents in NCA. Volatile samples were screened for their antibacterial and antifungal activities using agar diffusion method and minimum inhibitory concentrations. The cytotoxic activity was evaluated using viability assay in breast (MCF-7), colon (HCT-116) and lung carcinoma (A-549) cells by the MTT assay. The results revealed that NEA oil exhibited potential antimicrobial activity against most of the tested organisms and showed promising cytotoxicity.  相似文献   

8.
Eleven compounds were successfully separated from Asteris souliei by using a two‐step high‐performance counter‐current chromatography method. The first step involved a reversed phase isocratic counter‐current chromatography separation using hexane/ethyl acetate/methanol/water (1:0.8:1:1 v/v/v/v), which produced three fractions, the first two of which were mixtures. The second step used step‐gradient reversed‐phase counter‐current chromatography with hexane/butanol/ethyl acetate/methanol/water (1:0.5:3.5:1:4 v/v/v/v/v) initially followed by hexane/ethyl acetate/methanol/water (1:2:1:2 v/v/v/v) to separate Fraction 1 into seven compounds; and hexane/ethyl acetate/methanol/water (1:1:1:1.2 v/v/v/v) to separate Fraction 2 into three further compounds. The chemical structures of the separated compounds were identified by ESI‐MS and NMR spectroscopy (1H and 13C). Baicalin ( 5 ), eriodictyol ( 7 ), apigenin‐7‐glycoside ( 8 ), quercetin ( 9 ), luteolin ( 10 ), and apigenin ( 11 ) showed obvious inhibitory effects on lipopolysaccharide‐induced nitric oxide production in RAW264.7 cells at a concentration of 10 μg/mL.  相似文献   

9.
Five terpenoids, including two new ones, 3,7‐dioxo‐tirucalla‐8,24‐dien‐21‐oic acid ( 2 ) and 3α‐acetoxyl‐7‐oxo‐tirucalla‐8,24‐dien‐21‐oic acid ( 3 ), and three known ones, boscartol A ( 1 ), 11‐keto‐β‐boswellic acid ( 4 ), and acetyl‐11‐keto‐boswellic acid ( 5 ), have been extracted by the ultrapressure extraction and purified by pH‐zone‐refining countercurrent chromatography and high‐speed countercurrent chromatography from olibanum. For ultrapressure extraction, the optimal condition including 200 MPa of extraction pressure, ethyl acetate of extraction solvent, 1:20 (g/mL) of solid/liquid ratio, and 2 min of extraction time were obtained. For the separation, from 1.5 g of the terpenoid extract, 220.1 mg of 4 , 255.5 mg of 5 , and 212.3 mg of the mixture of 1 , 2 , and 3 were obtained by pH‐zone‐refining countercurrent chromatography under the solvent system of chloroform/ethyl acetate/methanol/water (3:1:3:2, v/v/v/v) with aqueous ammonia and trifluoroacetic acid as retention and eluter agents. The enriched mixture (210 mg) was further separated by conventional high‐speed countercurrent chromatography with petroleum ether/ethyl acetate/methanol/water (1:0.8:1.1:0.6, v/v/v/v), yielding 30.1 mg of 1 , 35.5 mg of 2 , 12.3 mg of 3 . The structures of these five terpenoids were elucidated by extensive spectroscopic methods.  相似文献   

10.
Volatile organic compounds (VOCs) are growing pollutants now that cause the serious environmental pollution and threaten human health. The functionalized ordered mesoporous silica (FOMS) has attracted considerable attention in adsorbing VOCs. In this paper, the molecular dynamics simulation was used to simulate the adsorption performance of FOMS on VOCs (acetone, ethyl acetate and toluene). After simulating different pore sizes (2 nm, 3 nm and 4 nm) adsorption performances of ordered mesoporous silica (OMS) on VOCs, OMS with a pore size of 4 nm was selected to further study the influence of functional groups (vinyl, methyl, and phenyl). The following law was obtained: the saturated adsorption capacities of vinyl-functionalized OMS (V-FOMS) to acetone, ethyl acetate and toluene were 3.045 mmol.g?1, 2.568 mmol.g?1 and 1.976 mmol.g?1 respectively; the saturated adsorption capacities of methyl-functionalized OMS (M-FOMS) to acetone, ethyl acetate and toluene were 2.798 mmol.g?1, 2.312 mmol.g?1 and 1.698 mmol.g?1 respectively; the saturated adsorption capacities of phenyl-functionalized OMS (P-FOMS) to acetone, ethyl acetate and toluene were 2.124 mmol.g?1, 1.941 mmol.g?1 and 1.539 mmol.g?1 respectively. These results show that the adsorption ability of FOMS for different adsorbates follows the sequence of acetone > ethyl acetate > toluene. Furthermore, the interaction between functional groups (vinyl, methyl and phenyl) in FOMS and VOCs was explored. It is found that the interaction between different functional groups and adsorbates is different (interaction energy effect). This interaction energy effect promotes FOMS to better adsorb VOCs. This work would provide fundamental understanding and guidance for the development of novel adsorption materials for the adsorption of VOCs.  相似文献   

11.
Withania somnifera has been used in Ayurvedic medicine for treatment of depression and inflammation, and as an aphrodisiac. It contains many phytochemicals such as Withaferine A, withanine, anahygrine, tropine, and withanolides. Of these, withaferine A is considered to be the most active compound. Withaferine A was estimated in herbal extract and polyherbal formulations by high performance thin layer chromatography (HPTLC). As there is no official HPTLC protocol for quantitation of the above phytochemicals, an attempt was made to quantify withaferine A in herbal extract and polyherbal formulations produced from Withania somnifera. Precoated silica gel G (aluminium backed) plates were used as stationary phase and toluene:ethyl acetate: formic acid (50 : 15 : 5) was used as mobile phase. Detection and quantification were performed by densitometry at λ 213 nm. The linear range was 1 μg to 3 μg. This HPTLC method was found to be reproducible, accurate, and precise.  相似文献   

12.
Direct in situ determination of PGE1 in dioxane/water (1:1) at concentrations between 50 μg/ml and 1 mg/ml is described. HPTLC of PGE1 was carried out on HPTLC Kieselgel 60 o.F. plates; application (200 nl) was with a Nano-Appllcator and ethyl acetate/formic acid (400:5, v/v) served as mobile phase. The spots were located by dipping the plates into a 3% cupric acetate solution in 15% aqueous phosphoric acid, followed by heating at 120°C for 15 min. The plates were then evaluated directly at λ = 345 nm by chromatogram spectrometry. The coefficient of variation is 3.6%.  相似文献   

13.
Partition coefficient is a key parameter for counter-current chromatography separation. High-performance liquid chromatography (HPLC) is the most commonly used tool for the screening of partition coefficients. However, HPLC technology is not applicable to the compounds present in the same chromatographic peak. Nuclear magnetic resonance (NMR) technology could easily distinguish compounds according to their characteristic absorption even if they exist in the same HPLC peak. In this study, two flavonoids present in the same HPLC peak were successfully purified by counter-current chromatography with a solvent system screened by NMR to show the great potential of NMR technology in the screening of the partition coefficient of co-efflux compounds. Through NMR screening, an optimized ethyl acetate/n-buthanol/water (7:3:10, v/v/v) system was applied in this study. As a result, two flavonoids, including 4.8 mg of 3′-methoxyl-6′’’-O-feruloylsaponarin and 9.8 mg of 6′’’-O-feruloylsaponarin were separated from 15 mg of the mixture. There is only one methoxy group difference between the two flavonoids. This study provides a new strategy for the screening of counter-current chromatography solvent systems and broadens the application scope of counter-current chromatography.  相似文献   

14.
Apocynin, androsin, together with picroside I, II and III from crude extracts of Picrorhiza scrophulariiflora were isolated by means of high‐speed counter‐current chromatography (CCC) combining elution‐extrusion (EE) and cycling‐elution (CE) approach. The EECCC took full advantages of the liquid nature of the stationary phase for a complete sample recovery and extended the solute hydrophobicity window, while CECCC showed its unique advantage in achieving effective separation of special compounds through preventing stationary phase loss. In the present work, the biphasic liquid system composed of n‐hexane/ethyl acetate/methanol/water (1:2:1:2, v/v/v/v) was used for separation of apocynin and androsin, ethyl acetate/n‐butanol/water/formic acid (4:1:5:0.005, v/v/v/v) for picroside I, II and III. However, due to the extremely similar K values (K1/K2≈1.2), picroside I and III were always eluted together by several biphasic solvent systems. In this case, the CECCC exhibited great superiority and baseline separated in the sixth cycle using ethyl acetate/water (1:1, v/v) as biphasic liquid system. Each fraction was analyzed by UPLC‐UV and ESI‐MS analysis, and identified by comparing with the data of reference substances. Compared with classical elution, the combination of EE and CE approach exhibits strong separation efficiency and great potential to be a high‐throughput separation technique in the case of complex samples.  相似文献   

15.
This study focuses on the characterization and classification of 42 medicinal plants extracts according to their antioxidant activity. Principal component analysis (PCA), cluster analysis (CA) and the combination of PCA with linear discriminant analysis (PCA-LDA) were used as multivariate exploratory techniques for chromatographic data analysis. For the separation of the compounds a mobile phase containing ethyl acetate: toluene: formic acid: water (30:1.5:4:3 v/v/v/v) and different HPTLC plates (Silica gel 60 and HPTLC Silica gel 60?F254) were used. The chromatographic plates were evaluated using the images obtained after spraying the plates with 2-aminoethyldiphenylborate solution (NTS, 0.2% in ethanol) and also after their reaction with 2, 2-diphenyl-1-picrylhydrazyl solution (DPPH?) (0.2% in ethanol). The score projection on the plane defined by first two components (PC1 and PC2) revealed two large groups of the investigated samples depicted according to their antioxidant capacity. A better classification of samples according to their antioxidant capacity was obtained using the CA and PCA-LDA methodology in all cases. The excellent results obtained in this study concerning the classification of medicinal plants according to their antioxidant capacity using the PCA-LDA methodology applied to TLC chromatograms might lead to a new paradigm in the field of medicinal plant holistic evaluation.  相似文献   

16.
Yu LS  Xu XQ  Huang L  Ling JM  Chen GN 《Electrophoresis》2008,29(3):726-733
A selective and sensitive method of microemulsion EKC (MEEKC) with electrochemical detection (ED) was developed for separation and determination of 14 flavonoids. In order to obtain the better stability for the studied flavonoids, oil (ethyl acetate) with low interfacial surface tension was employed as organic solvent. A running buffer composed of 0.9% (w/v, 30 mM) SDS, 0.9% (w/v, 21 mM) sodium cholate (SC), 0.9% (w/v, 121 mM) butan-1-ol, 0.6% (w/v, 68 mM) ethyl acetate, and 98.2% v/v 10 mM Na(2)B(4)O(7)-20 mM H(3)BO(3) buffer (pH 7.5) was applied for the separation of flavonoids. Under the optimum conditions, the relationship between peak currents and analyte concentrations was linear over about 1.3 and 1.7 orders of magnitude with detection limits (defined as S/N = 3) ranging from 0.02 to 0.5 microg/mL for all analytes. This method was applied for the determination of flavonoids in real samples with simple extraction procedures, and the assay results were satisfactory.  相似文献   

17.
A simple and rapid high‐performance thin‐layer chromatographic method was developed for the separation and determination of six flavonoids (rutin, luteolin‐7‐O‐β‐glucoside, chamaemeloside, apigenin‐7‐O‐β‐glucoside, luteolin, apigenin) and one coumarin, umbelliferone from chamomile plant samples and dietary supplements. The separation was achieved on amino silica stationary phase using dichloromethane/acetonitrile/ethyl formate/glacial acetic acid/formic acid (11:2.5:3:1.25:1.25 v/v/v/v/v) as the mobile phase. The quantitation of each compound was carried out using densitometric reflection/absorption mode at their respective absorbance maxima after postchromatographic derivatization using natural products reagent (1% w/v methanolic solution of diphenylboric acid‐β‐ethylamino ester). The method was validated for specificity, limits of detection and quantification, precision (intra‐ and interday) and accuracy. The limits of detection and quantification were found to be in the range from 6–18 and 16–55 ng/band for six flavonoids and one coumarin, respectively. The intra‐ and interday precision was found to be <5% RSD and recovery of all the compounds was >90%. The data acquired from high‐performance thin‐layer chromatography was processed by principal component analysis using XLSTAT statistical software. Application of principal component analysis and agglomerative hierarchial clustering was successfully able to differentiate two chamomiles (German and Roman) and Chrysanthemum.  相似文献   

18.
Densities, excess molar volumes, refractive indices, and changes in refractive index on mixing for (ethyl acetate  +  benzene, or methylbenzene, or ethylbenzene, or 1-4-dimethylbenzene, or 1-methylethylbenzene, or 1-3-5-trimethylbenzene, or 1-1-dimethylethylbenzene) have been determined atT =  298.15 K. The excess molar volumes and changes in refractive index have been fitted to Redlich–Kister polynomials. The π -electrons interactions of the benzene ring and the peculiar plate shape of the aromatic molecules are noticeably modified by the presence of the ethyl acetate molecules of a different nature. The intermolecular interactions are strongly modified and result in positive excess volumes except for toluene or p -xylene whose values are close to zero. The refractive indices were compared with calculated values using mixing rules proposed by several authors.  相似文献   

19.
K&#;l&#;&#;  B.  &#;zden  T.  Toptan  S.  &#;zilhan  S. 《Chromatographia》2007,66(1):129-133

A specific and sensitive liquid chromatography-electrospray ionization tandem mass spectrometry method was developed for the determination of zolmitriptan and N-desmethylzolmitriptan in human plasma. The analytes and the internal standard (IS) paroxetine were extracted by liquid–liquid extraction with a mixture of saturated ethyl acetate:dichloromethane (4:1) and were separated using an isocratic mobile phase on a XTerra RP18 column. The mobile phase used was acetonitrile: 5 mM ammonium acetate: formic acid (50:50:0.053, v/v/v). Zolmitriptan and N-desmethylzolmitriptan in a range of 0.25–20 ng mL−1 were easily quantified. The validated method can be applied to pharmacokinetic and bioequivalence studies.

  相似文献   

20.
《Arabian Journal of Chemistry》2020,13(11):7843-7850
In continuation of our work on genus Euphorbia, the phytochemical investigation of ethyl acetate fraction of the aerial parts of Euphorbia geniculata Ortega (Eg) family Euphorbiaceae revealed the isolation and identification of eight polyphenolic compounds; gallic acid (1), ellagic acid (2), quercetin-3-O-rutinoside) (rutin) (3), quercetin-3-O-glucopyranoside-7-O-rhamnoside (4), quercetin-3-O-rhamnoside (5), quercetin-3-O-β-D- glucopyranoside (6), and quercetin-3-O-β-D-arabinoside (7) and quercetin (8) using spectrophotometric and physicochemical analysis. Quantitative estimation of total flavonoids and phenolics contents were carried out for total methanolic extract. Biological activities of ethyl acetate fraction including nephroprotective and antioxidant activities were evaluated for the first time. The nephroprotective potential of Eg was evaluated in male rats with thioacetamide induced kidney injury. Antioxidant activity was evaluated using DPPH method.Results; Quantitative estimation of total phenolics and flavonoids content in the total methanolic extract of Eg revealed high phenolics content (285.4 mg GAE /gm extract) in comparison with flavonoids content (36.9 mg RE /gm extract). Isolation and characterization of eight polyphenolic compounds. The nephroprotictive activity was studied using thioacetamide as nephrotoxicant agent resulted in marked nephrotoxicity. While pretreatment of rats with ethyl acetate fraction of Eg significantly attenuated the nephrotoxicity through alteration of kidney biomarkers, improving the redox status of the tissue and so brought the serum biochemical parameters nearly toward the normal levels. The study revealed significant antioxidant activity of Eg in comparison with ascorbic acid. Conclusion; The results suggested that E. geniculata Ortega ethyl acetate fraction could be used in future therapy as nephroprotective and antioxidant drugs of natural source.  相似文献   

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