Effects of different extraction methods and conditions on the phenolic composition of mate tea extracts

A simple and rapid HPLC method for determination of chlorogenic acid (5-O-caffeoylquinic acid) in mate tea extracts was developed and validated. The chromatography used isocratic elution with a mobile phase of aqueous 1.5% acetic acid-methanol (85:15, v/v). The flow rate was 0.8 mL/min and detection by UV at 325 nm. The method showed good selectivity, accuracy, repeatability and robustness, with detection limit of 0.26 mg/L and recovery of 97.76%. The developed method was applied for the determination of chlorogenic acid in mate tea extracts obtained by ethanol extraction and liquid carbon dioxide extraction with ethanol as co-solvent. Different ethanol concentrations were used (40, 50 and 60%, v/v) and liquid CO? extraction was performed at different pressures (50 and 100 bar) and constant temperature (27 ± 1 °C). Significant influence of extraction methods, conditions and solvent polarity on chlorogenic acid content, antioxidant activity and total phenolic and flavonoid content of mate tea extracts was established. The most efficient extraction solvent was liquid CO? with aqueous ethanol (40%) as co-solvent using an extraction pressure of 100 bar.     

Extractive substances formed from buckwheat grain production waste

Properties of liquid and dry extracts produced in treatment of buckwheat fruit shells (husk) and straw with water or an acid solution were studied. The conditions of pigment concentration from aqueous extracts by ultrafiltration were determined.     

High performance liquid chromatographic determination of chlophedianol hydrochloride in "jung fei", a complex tablet formulation

A high performance liquid chromatographic method is presented for the determination of chlophedianol hydrochloride in a complex tablet formulation. Tablets are dissolved in a water/acetonitrile (50/50) mixture. Samples are separated on an octadecylsilane column with a mobile phase of 70% acetonitrile and 30% aqueous solution of 0.005M 1-octanesulfonic acid, 1% acetic acid, and 1% diethylamine. Effluent is monitored by a spectrophotometric detector with a 254-nm filter. Chlophedianol is separated from a complex mixture of plant extracts and fillers in the tablets.     

Spectrophotometric determination of trace amounts of cobalt using 7-Nitroso-8-hydroxyquinoline-5-sulphonic acid as reagent

A thinlayer chromatographic method for the quantitative determination of phthalic acid esters in aqueous PVC-plastic extracts has been developed. Petroleum ether/diethyl ether/glacial acetic acid (8∶2∶0.1) is used as solvent; the plates are coated with 0.2 mm of silica gel with fluorescent agent. After separation and elution a photometric determination is performed.     

吡啶离子液体双水相-高效液相色谱法同时测定牛奶中3种喹诺酮药物残留

建立了吡啶离子液体双水相-高效液相色谱同时测定牛奶中噁喹酸、萘啶酸及氟甲喹3种喹诺酮药物残留的方法. 牛奶样品经氯化钠和磷酸混合溶液提取后, 采用吡啶离子液体N-乙基-2-甲基吡啶溴化盐([EMPy]Br)和K2HPO4形成的双水相体系萃取富集, 以0.1%磷酸水溶液-乙腈为流动相, 梯度洗脱, 紫外检测. 该方法对噁喹酸、萘啶酸和氟甲喹测定的线性范围分别为0.3~15, 0.5~20和0.5~25 μg/mL, 相关系数(r)均大于0.9997, 3种药物的检出限在8~10 μg/kg之间. 对不同加标浓度的牛奶样品测定, 绝对回收率均在86.4%~94.8%范围内, 相对标准偏差为3.6%~8.3%. 该方法对牛奶中喹诺酮药物残留的检测具有简单、快速、环保和灵敏度高等优点.     

Thin-layer chromatography of alkaloids on cyanopropyl bonded stationary phases. Part I

Selected alkaloids are chromatographed on cyanopropyl-silica thin layers using various nonaqueous and aqueous eluents. Because of the strong retention of these basic compounds, nonaqueous eluents containing medium polar diluents, strongly polar modifiers, and silanol blockers (ammonia or diethylamine) are required for separation. Likewise, aqueous eluents containing modifiers (acetonitrile, methanol, and tetrahydrofuran), buffered aqueous solutions at pH 2-8, ion-pair reagents [octane sulfonic acid sodium salt, sodium dodecyl sulphate, and bis-(2-ethylhexyl)phosphoric acid], or silanol blockers (ammonia, tetrabutyl ammonium chloride, and diethyl amine) are investigated. The separation selectivity as well as spot symmetry and efficiency system in the applied eluent systems are analyzed. The most selective and efficient systems are used in two-dimensional separations of isoquinoline alkaloids' mixture and the plant extracts Chelidonium majus, Fumaria officinalis, and Glaucium flavum. Two-dimensional thin-layer chromatography on cyanopropyl layer with diode array detection densitometry enables the separation and identification of some alkaloids in plant extracts.     

THE APPLICATION OF A NOVEL ADSORBENT IN RAPID SAMPLE CLEAN—UP OF GINKGOLIDES AND BILOBALIDE IN EXTRACTS OF GINKGO BILOBA LEAVES

A rapid method has been developed for rapid sample clean-up in the determination of the pharmacologically active terpenoid including ginkgolide A,B,C and bilobalide in ginkgo biloba leaves extracts (GBE).The extracts are dissolved in 7% of ethanol aqueous solution and then purified by a highly selective polyeric adsorbent solid-phase chromatographic column.After being concentrated,the separated terpenoids with no phenolic distrubance are determined by highperformance liquid chromatorgraphy on a Nova-Pak C18 column with methanol-water(30:70)as effluent and refractive index detection.The recovery of the method is about 95% and the new method saves more time than the conventional two-column purification method.     

The Intehaction of Aqueous Solutions of Chlorine with Malic Acid,Tartaric Acid,and Various Fruit Juices: A Source of Mutagens

Abstract

The interactions of aqueous solutions of chlorine with some fruit acids (citric acid, DL-malic acid, arid L-tartaric acid) at different pH values were studied. Diethyl ether extraction followed by GC/MS analysis indicated that a number of mutagens (certain chlorinated propanones and chloral hydrate) are present as major products in some of these samples. A number of fruit juices (orange, grape, apple, pineapple, and grapefruit) were also treated with aqueous solutions of chlorine at their pH values. The products were analyzed by GC/MS. The same mutagens that were formed by the pure acids (citric acid and DL-malic acid) were identified as major products in ether extracts of these samples. Another mutagen, dichloroacetonitrile, was also identified as a minor product in some of these juice samples. All of the major products observed in the chlorination of all five fruit juices are potentially derived from reactions of aqueous solutions of chlorine with citric or malic acid and with trace amounts of acetaldehyde and acetone in the juices. The minor product, dichloroacetonitrile, is likely derived from the chlorination of certain amino acids in the fruit juices.     

Conjugated ketonic fatty acids from Pleurocybella porrigens

Three novel conjugated long-chain fatty acids (1-3) were obtained from aqueous methanol extracts of Pleurocybella porrigens together with nine known constituents including (8E,10E)-7,12-dioxo-8,10-octadecadienoic acid (ostopanic acid) (4). The structures of the new fatty acids were characterized as (14RS)-(10E,12E)-14-hydroxy-9-oxo-10,12-octadecadienoic acid (1), (12RS)-(8E,10E)-12-hydroxy-7-oxo-8,10-octadecadienoic acid (2), and (10E,12E)-9,14-dioxo-10,12-octadecadienoic acid (3) by spectroscopic methods.     

Assessment of the Efficacy of Olive Leaf (Olea europaea L.) Extracts in the Treatment of Colorectal Cancer and Prostate Cancer Using In Vitro Cell Models

Cancer is one of the most serious public health issues worldwide, ranking second only to cardiovascular diseases as a cause of death. Numerous plant extracts have extraordinary health benefits and have been used for centuries to treat a variety of ailments with few side effects. Olive leaves have a long history of medicinal and therapeutic use. In this study, the anti-cancer properties of an olive leaf extract were investigated in vitro using colorectal and prostate cancer cell lines (HT29 and PC3, respectively). A high-performance liquid chromatography analysis showed that the olive leaf extract contained a high chlorogenic acid content. Accordingly, chlorogenic acid may be related to the observed effects of the aqueous extract on cancer cells, including increased inhibition of cancer cell growth, migration, DNA fragmentation, cell cycle arrest at the S phase, reactive oxygen species (ROS) production, and altered gene expression. The effects of the extracts were greater in HT29 than in PC3 cells. These results suggest that chlorogenic acid, the main constituent in the olive extract, is a promising new anti-cancer agent. Further analyses should focus on its in vivo effects on colorectal tumor models, both alone and in combination with established agents.     

Preservative Effect of Aqueous and Ethanolic Extracts of the Macroalga Bifurcaria bifurcata on the Quality of Chilled Hake (Merluccius merluccius)

This work addressed the preservative behaviour of different icing media containing extracts from the alga Bifurcaria bifurcata. A comparative study of the antimicrobial and antioxidant effects of aqueous and ethanolic extracts of this macroalga was carried out. Whole hake (Merluccius merluccius) pieces were stored in ice containing either kind of extract and analysed for quality changes throughout a 13-day storage period. A progressive loss of microbial and biochemical quality was detected in all batches as chilling time increased. A significant inhibitory effect (p < 0.05) on microbial activity could be observed as a result of including the aqueous (lowering of psychrotrophic and lipolytic counts and pH value) and ethanolic (lowering of psychrotrophic and lipolytic counts) extracts. Additionally, both kinds of extract led to a substantial inhibition (p < 0.05) in the lipid hydrolysis rate (formation of free fatty acids), greater in the case of the batch containing ethanolic extract. Concerning lipid oxidation, a similar inhibitory effect (p < 0.05) on the formation of secondary compounds (thiobarbituric acid substances) was noticed in fish specimens corresponding to both alga extracts; however, more (p < 0.05) peroxide formation was detected in fish corresponding to the ethanolic extract batch. A preservative effect can be concluded for both kinds of extract; this effect agrees with previous studies reporting the presence of hydrophilic and lipophilic bioactive compounds in B. bifurcata.     

Determination of tungstate in soils and sludges by using single-column ion chromatography

A procedure has been developed for the determination of tungstate at trace levels in aqueous extracts of soil and sludge by single-column ion chromatography (SCIC). Chromatographic parameters based on ion selectivity, time of determination and signal response were optimized for tungstate with the simultaneous detection of nitrate and sulfate. Chloride, phosphate, chromate, molybdate and vanadate were found not to interfere in the determination. A low-capacity resin-based column was used for the separation with p-hydroxybenzoic acid (5 mM) at pH 8.5 as the eluent. The limit of detection defined as three times the signal-to-noise ratio was 170 μg l^?1 (2-ml sample). The resolution between tungstate and sulfate was R_s=2.84. The results for aqueous extracts agree closely with those obtained by an accepted spectrophotometric method.     

Determination of betaines as ultraviolet-absorbing esters

A method is described for the estimation of fully N-methylated amino acids (betaines) in plant extracts. After partial purification of aqueous extracts with ion-exchange resins, a crown ether and potassium phosphate buffer are used to facilitate the esterification of betaines with α, p-dibromoacetophenone, p-nitrobenzyl bromide or α-bromo-p-tolunitrile. The esters are isolated with dilute sulphuric acid and chloroform; 10–200 nmol can be determined spectrophotometrically, and smaller amounts by high-performance liquid chromatography.     

THE APPLICATION OF A NOVEL ADSORBENT IN RAPID SAMPLE CLEAN-UP OF GINKGOLIDES AND BILOBALIDE IN EXTRACTS OF GINKGO BILOBA LEAVES

1 INTRODUCTIONGinkgolides, known as specific antagonist of platelet factor (PAF), possess uniquepharmaceutical properties and are main active constituent of many phytopharrnaceuticpreparations based on ginkgo bilioba leaves extracts II]. Another active terpenoid, namelybilobalide, is reported recently to show potent therapeutic efficacy to the disease related to nervesystem 121. They are all terpene lactones, which are highly oxidized as illustrated in Figure 1.The first attempts to ana…     

Antioxidant activity of organic and aqueous leaf extracts of Cassia occidentalis L. in relation to their phenolic content

In this study, the antioxidant potency of sequential organic and aqueous leaf extracts of Cassia occidentalis was investigated, employing various established in vitro systems such as nitric oxide scavenging (NOS) activity, β-carotene-linoleic acid model system, hydroxyl radical scavenging (HRS) activity, reducing power, metal chelating activity (MCA) and superoxide radical scavenging (SRS) activity. The aqueous extract of the leaves of C. occidentalis was found to be most effective against free radicals, followed by the methanolic, chloroform, petroleum ether and benzene extracts, respectively. A preliminary study of qualitative and quantitative estimations of phenolics was performed, and the results were correlated with different antioxidant tests. A positive and significant (p?相似文献   

Assessment of total arsenic and arsenic species stability in alga samples and their aqueous extracts

In order to achieve reliable information on speciation analysis, it is necessary to assess previously the species stability in the sample to analyse. Furthermore, in those cases where the sample treatment for species extraction is time-consuming, an assessment of the species integrity in the extracts is of paramount importance. Thus, the present paper reports total arsenic and arsenic species stability in alga samples (Sargassum fulvellum and Hizikia fusiformis), as well as in their aqueous extracts, which were stored in amber glass and polystyrene containers at different temperatures. Total arsenic determination was carried out by inductively coupled plasma atomic emission spectroscopy (ICP-AES), after sample acid digestion in a microwave oven, while arsenic speciation was conducted by anion exchange high performance liquid chromatography on-line coupled to ICP-AES, with and without sample introduction by hydride generation (HPLC-ICP-AES and HPLC-HG-ICP-AES), after aqueous microwave-assisted extraction. The results obtained for solid alga samples showed that total arsenic (for Hijiki alga) and arsenic species present (As(V) for Hijiki and NIES No. 9 Sargasso) are stable for at least 12 months when samples are stored in polystyrene containers at +20 degrees C. On the other hand, a different behaviour was observed in the stability of total arsenic and As(V) species in aqueous extracts for both samples, being the best storage conditions for Sargasso extracts a temperature of -18 degrees C and polystyrene containers, under which they are stable for at least 15 days, while Hijiki extracts must be stored in polystyrene containers at +4 degrees C in order to ensure the stability for 10 days.     

Extraction of europium from nitrate solutions in the presence of tris(hydroxymethyl)aminomethane and characterization of the products of pyrolysis of extracts

The extraction of europium by neat benzene and benzene solutions of tributyl phosphate (TBP) and benzoic acid (BA) was studied in the presence of tris(hydroxymethyl)aminomethane (THMAM). Based on europium distribution in these extraction systems in combination with the IR and luminescence spectra of extracts, we infer that well-extractable europium complexes with THMAM are formed. We demonstrate that introduction of THMAM into aqueous nitrate solutions considerably enhance europium extraction. The compositions are determined and some magnetic properties of pyrolysis products of extracts are studied.     

Antioxidant effect of Stryphnodendron rotundifolium Martius extracts from Cariri-Ceará State (Brazil): potential involvement in its therapeutic use

Stryphnodendron rotundifolium is a phytotherapic used in the northeast of Brazil for the treatment of inflammatory processes which normally are associated with oxidative stress. Consequently, we have tested the antioxidant properties of hydroalcoholic (HAB) and aqueous extracts (AB) from the bark and aqueous extract (AL) from the leaves of Stryphnodendron rotundifolium to determine a possible association between antioxidant activity and the popular use of this plant. Free radical scavenger properties were assessed by the quenching of 1',1'-diphenil-2-picrylhydrazyl (DPPH) and the calculated IC(50) were: HAB = 5.4 ± 0.7, AB = 12.0 ± 2.6, and AL = 46.3 ± 12.3 μg/mL. Total phenolic contents were: HAB = 102.7 ± 2.8, AB = 114.4 ± 14.6, and AL = 93.8 ± 9.1 μg/mg plant). HPLC/DAD analyses indicated that gallic acid, catechin, rutin and caffeic acid were the major components of the crude extracts of S. rotundifolium. Plant extracts inhibited Fe(II)-induced lipid peroxidation in brain homogenates. Iron chelation was also investigated and only HBA exhibited a weak activity. Taken together, the results suggest that S. rotundifolium could be considered an effective agent in the prevention of diseases associated with oxidative stress.     

Extraction separation of cadmium and zinc with tetra-n-butylammonium iodide

Tetra-n-butylammonium iodide (TBAI) forms associations in chloroform and aqueous solutions. A TBAI solution in chloroform extracts hydroiodic acid by addition. From 0.5M hydroiodic acid medium cadmium is quantitatively extracted into a TBAI solution in chloroform. Under these conditions zinc is not extracted. This makes possible the extractive separation of cadmium from zinc in micro-or macroamounts.     

Determination of sarin, soman and their hydrolysis products in soil by packed capillary liquid chromatography-electrospray mass spectrometry

An analytical method based on aqueous ultrasonic extraction and packed capillary liquid chromatography-electrospray mass spectrometry (LC-ESI-MS) analysis was developed and compared to an existing gas chromatography(GC)-MS based method for the determination of sarin, soman and their hydrolysis products in contaminated soil. Three soils, a red clay, a tan sandy clay and a brown sandy clay loam, were spiked with sarin and soman and their initial hydrolysis products, isopropyl methylphosphonic acid and pinacolyl methylphosphonic acid, at the 10 microg/g level to assess recovery efficiency. Recovery of sarin and soman from the aqueous soil extracts was comparable to the existing analytical method, with a significant improvement in recovery being demonstrated for the chemical warfare agent hydrolysis products. Sarin and soman were recovered in the 20-90% range from the three soil types with aqueous extraction, while the hydrolysis products of these chemical warfare agents were extracted with recoveries in excess of 80%. The developed soil extraction and analysis method appears to be an attractive alternative to the GC-MS based method, since aqueous extracts containing chemical warfare agent hydrolysis products may be analysed directly, eliminating the need for additional sample handling and derivatization steps.