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Agrokémia és Talajtan
Authors: Szandra Baklanov, Ágota Horel, Györgyi Gelybó, Eszter Tóth, Márton Dencső, Emese Ujj and Imre Potyó

Összefoglalás

Jelen tanulmányban megvizsgáltuk a nitrogén átalakulással kapcsolatos nitrogén forgalmi folyamatok módosulását a nitrogénkötés-, a denitrifikáció-,- illetve a nitrifikációs aktivitás mérésével. A vizsgálatok alapanyagaként különböző földhasználati területekről származó talajmintákat használtunk fel. Az anyaggyőjtés helyszíneként a Balaton-felvidéken elterülő 21 km2 kiterjedéső vízgyőjtő terület szolgált. A talajmintákat hat földhasználati területről győjtöttük, úgy, mint tölgyesakácos, tölgyes, szőlő, szántó, gyümölcsös és rét.

A nitrogén forgalommal kapcsolatos laboratóriumi kísérletek sötét, és szabályozott hőmérsékleti körülmények között kerültek kivitelezésre, három hőmérsékleten (10 °C, 20 °C, 30 °C). Ennek célja az volt, hogy a vízgyőjtő területén előforduló hőmérsékleti körülményeket megfelelően tudjuk modellezni.

A potenciális nitrogénkötés vizsgálatánál pozitív korrelációt találtunk, vagy érdemi változást nem figyeltünk meg a hőmérséklet függvényében. A szántó, gyümölcsös illetve a rét talajmintáinál a nitrogénkötést mutató értékek csökkenését észleltük a hőmérséklet növelésével (10-20 °C). Az erdőből származó talajmintákban ugyanakkor nem tapasztaltunk változást. 30 °C hőmérsékleten szignifikáns növekedést kaptunk a nitrogénkötési potenciálok tekintetében (p < 0,05), a 10 °C, illetve 20 °C hőmérsékleten mért adatokkal összevetve.

A talajok nettó nitrifikációs potenciáljának vizsgálatakor negatív korrelációt figyeltünk meg magasabb hőmérsékleteken. A legnagyobb értékeket 10 °C hőmérsékleten, míg a legalacsonyabb eredményeket 30 °C hőmérsékleten mértük.

Az erdei talajok elemzése során nem jegyeztünk fel lényeges különbségeket a potenciális denitrifikációs folyamat különböző hőmérsékleteken mért eredményei között. A többi, eltérő földhasználati területről származó minták változó hőmérsékleten feljegyzett értékei között azonban jelentős eltéréseket tapasztaltunk (p < 0,05).

Összességében úgy találtuk, hogy egy terület mővelési módja jelentősen befolyásolhatja a talaj nitrogén forgalmának alakulását, különösen azokban az esetekben, amikor tápanyagutánpótlás is történik. A jelen tanulmány adatai alapján megállapítottuk, hogy a vizsgált vízgyőjtőn az emberi behatásoknak kisebb mértékben kitett területek nitrogén körforgalmi folyamatai kevésbé érzékenyek a hőmérsékleti változásokra.

Open access
Acta Chromatographica
Authors: Aixia Han, Guanyang Lin, Jinzhang Cai, Qing Wu, Peiwu Geng, Jianshe Ma, Xianqin Wang and Chongliang Lin

An ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method was established to determine hirsutine and hirsuteine in rat plasma. Pharmacokinetics of hirsutine and hirsuteine in rats after intravenous or oral administration has been investigated using this developed UPLC–MS/MS method, and bioavailability of the two drugs was calculated. Diazepam was used as internal standard, and UPLC BEH column (2.1 mm × 50 mm, 1.7 μm) was used at temperature of 40 °C. The mobile phase was composed of acetonitrile and water (containing 0.1% formic acid) at a gradient elution flow rate of 0.4 mL/min. Nitrogen was used as desolvation gas (800 L/h) and conical gas (50 L/h). The multiple reaction monitoring (MRM) model was applied to quantitatively analyze hirsutine m/z 369 → 226, hirsuteine m/z 367 → 169.9, and diazepam (internal standard) m/z 285.1 → 193.3. Rat plasma samples were deproteinized using acetonitrile prior to UPLC–MS/MS analysis. Within the concentration range of 1–200 ng/mL, the linearity of hirsutine and hirsuteine in plasma was good (r > 0.995), and the lower limit of quantitation was 1 ng/mL. Relative standard deviations of intra-day precision for hirsutine and hirsuteine were ≤6.1% and ≤5.9%, respectively, and those of inter-day precision were ≤6% and ≤7.7%. Accuracy for hirsutine and hirsuteine ranged between 92.3% and 104.8%. Bioavailability of hirsutine and hirsuteine was 4.4% and 8.2%, respectively. The method is sensitive and fast with good selectivity and was successfully applied in the pharmacokinetic studies after intravenous and oral administration of hirsutine and hirsuteine.

Open access
Acta Chromatographica
Authors: Weijian Ye, Wei Sun, Ruijie Chen, Zhe Wang, Xiao Cui, Hui Zhang, Shuyi Qian, Qi Zheng, Yangfeng Zhou, Jiafeng Wan, Jiali Xu, Xianqin Wang and Yunfang Zhou

Galangin (GAL), the major bioactive flavonol extracted from Alpinia officinarum Hance (Zingiberaceae), has attracted much attention due to its multiple biological activities. To develop a fast, reliable, and sensitive ultrahigh-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) method for the quantification of GAL in rat plasma and mouse tissues. UHPLC–MS/MS using electrospray ionization operating in negative-ion mode was used to determinate GAL in 18 rats receiving three doses of GAL (2 and 9 mg/kg by intravenous injection, 5 mg/kg by oral administration), with six rats for each dose. Blood samples were collected at 0.0333, 0.25, 0.5, 1, 2, 4, 6 and 8 h. A total of 25 mice received 18 mg/kg GAL by intraperitoneal injection. Liver, heart, lung, spleen, brain, and kidney tissue samples were collected at 0.25, 0.5, 2, 4, and 6 h. The precision of the method was better than 12.1%, while the accuracy ranged from −4.8% to 8.1%. The results of pharmacokinetics demonstrated rapid GAL absorption (t max of 0.25 h), fast elimination (t 1/2 <1.1 h) after three different dosages, and an absolute bioavailability of ~7.6%. Tissue distribution analysis revealed abundant GAL in liver, kidney, spleen, and lung and smaller amounts in brain. The developed method proved fast (3 min), efficient, and reliable, with high selectivity for the quantitative analysis of GAL in biological samples. This is the first study to identify the target tissues of GAL, and the results may help to elucidate the mechanisms underlying its therapeutic effects in vivo.

Open access
Acta Chromatographica
Authors: Ruijie Chen, Mengrou Lu, Xiaoting Tu, Wei Sun, Weijian Ye, Jianshe Ma, Congcong Wen, Xianqin Wang and Peiwu Geng

We developed an ultra-performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS) method for quantification of panasenoside pharmacokinetics in rat plasma and tissue distribution in mouse. Twelve male Sprague-Dawley rats were used for pharmacokinetics after intravenous (2 or 10 mg/kg) administration of panasenoside, six rats for each dose. Thirty mice were randomly divided into six groups (five mice for each group, one group for each time point) and received 20 mg/kg of panasenoside by intraperitoneal administration. Calibration plots were in the range of 2–2000 ng/mL for panasenoside in rat plasma and 2–3000 ng/mL in mouse tissues. The relative standard deviation (RSD) of inter-day and intra-day precision was less than 14%. The accuracy was between 89.6% and 110.0%. The AUC(0–t) was 160.8 ± 13.0 and 404.9 ± 78.0 ng/mL*h, and t 1/2 of 3.2 ± 1.2 and 4.6 ± 1.7 h, CL (clearance) of 10.0 ± 2.0, and 21.4 ± 2.0 L/h/kg after intravenous administration 2 mg/kg and 10 mg/kg of panasenoside, respectively. The tissue distribution results indicated that the panasenoside diffuses rapidly and widely into major organs. The level of panasenoside was highest in mouse liver, followed by kidney, lung, and spleen. The overwhelming accumulation in liver indicated that liver was responsible for the extensive metabolism.

Open access
Acta Chromatographica
Authors: Omar M. Khalaf, Mosad A. Ghareeb, Amal M. Saad, Hassan M. F. Madkour, Ahmed K. El-Ziaty and Mohamed S. Abdel-Aziz

Different solvent extracts of the aerial parts of Senna italica (Mill.) were investigated for their chemical constituents and biological activities. Moreover, bio-guided fractionation led to isolation and identification of six compounds, namely: physcion (1), emodin (2), 2-methoxy-emodin-6-O-β-d-glucopyranoside (3), 1-hydroxy-2-acetyl-3-methyl-6-hydroxy-8-methoxynaphthalene (tinnevellin) (4), quercetin 3-O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (rutin) (5), and 1,6,8-trihydroxy-3-methoxy-9,10-dioxo-9,10-dihydroanthracene (6). The chemical structures of these compounds were established via 1D and 2D 1H- and 13C-NMR spectroscopy. Ethyl acetate and n-butanol extracts as well as compound 3 were evaluated for their anticancer activity against tumor cell lines. The tested extracts showed a moderate to weak activity, while compound 3 showed a moderate activity against human liver cancer (Hep G2) and breast cancer (MCF-7) cell lines with IC50 values of 57.5 and 42.3 μg/mL, respectively. Both ethyl acetate and n-butanol extracts exhibited antimicrobial activities with different strengths, i.e., ethyl acetate exhibited antimicrobial activity against seven test microbes while n-butanol extract showed antimicrobial activity against all tested microbes. This is the first report for the isolation of compound 3 as a new compound from S. italica growing in Egypt.

Open access

A simple, economic, rapid, reliable, and stability-indicating high-performance liquid chromatography (HPLC) method has been developed and validated for the simultaneous determination of paracetamol (PCM) and caffeine (CF) in solid dosage form. The chromatographic separations were achieved with a Waters Symmetry® C18 column (5 μm, 4.6 × 150 mm), using a mixture of methanol and water (40:60, v/v) as a mobile phase, under isocratic elution mode with a flow rate of 0.8 mL/min, and ultraviolet (UV) detection was set at 264 nm. The oven temperature for the column was set and maintained at 35 °C. The method was validated according to International Conference on Harmonization (ICH) guidelines, and it demonstrated excellent linearity, with a correlation coefficient of 1 and 0.9999 for PCM and CF, respectively, over the concentration ranges of 15–300 μg/mL (PCM) and 2.5–50 μg/mL (CF). The retention time (t R) was found to be 2.6 ± 0.001 and 3.5 ± 0.002 min for PCM and CF, respectively. Extensive stress degradation studies were conducted by subjecting the analytes to various stress conditions of acidic and alkaline hydrolysis as well as oxidative, photolytic, and heat degradations. The method was found to efficiently separate the analytes' peaks from that of the degradation products, without any variation in their retention times. The relative standard deviation (RSD) values of all recoveries for PCM and CF were less than 1.3%. The method was found to be suitable for routine analysis of PCM and CF in pharmaceutical dosage form.

Open access
Acta Chromatographica
Authors: Su Lian-Lin, Cheng Xue, Ding Xi-Yan, Mao Chun-Qin, Lu Tu-Lin, Hao Min, Li Ping and Qin Sirui

In this research study, a rapid, sensitive, and specific high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry (HPLC–ESI–MS/MS) method was established and validated, in regard to the simultaneous quantification of five sedative and hypnotic lignans (schisandrin, schisandrol B, schisantherin A, deoxyschisandrin, and schisandrin B) in various tissues of rats (including heart, liver, spleen, lung, and kidney). The purpose of the study was to clarify the tissue distribution of the total lignans extract of Schisandra chinensis (SC). Then, the analytes were separated on a MERCK Purospher STAR LP C18 column (250 mm × 4.6 mm, 5 μm), with a mobile phase consisting of 0.05% (v/v) formic acid acetonitrile, and 0.05% (v/v) formic acid water, and a flow rate of 1 mL/min. All of the calibration curves of the five components showed good linearity (r > 0.9950), with ranges of 4.8 to 1920 ng/mL for analytes. The intra-day and inter-day precisions (relative standard deviation [RSD] %) were within 13.76% for all of the analytes. The average recoveries of the five analytes were greater than 85.23%, and the mean value of the matrix effect ranged from 82.3% to 93.4%. The five analytes were confirmed to be stable during the storage, preparation, and analytic procedures. The major target tissues of the total lignans extract of the SC in the rats were the livers and kidneys.

Open access
Agrokémia és Talajtan
Authors: Ravi Kumar Gangwar, Marianna Makádi, Márta Fuchs, Ádám Csorba, Erika Michéli, Ibolya Demeter, András Táncsics and Tamás Szegi

Összefoglalás

A hazánk területének megközelítően 10%-át fedő szikes talajokban zajló talajkémiai folyamatok részletes vizsgálatával ellentétben, a talajmikrobiológiai folyamatokról és állapotokról kevesebb ismerettel rendelkezünk. Munkánkban ezért egy réti szolonyec talaj kémiai, fizikai és mikrobiológiai tulajdonságait vizsgáltuk szántó és rét hasznosítású területen.

Munkánk célja a rét és szántó művelési ág talajkémiai, -fizikai és - mikrobiológiai tulajdonságainak megállapítása, a kémiai és mikrobiológiai tulajdonságok közötti kapcsolatok feltárása réti szolonyec talajon, ahol a korábbi vizsgálatok elsősorban a talajkémiai változásokra koncentráltak.

A szántó és rét művelési ág talaja egyes kémiai és mikrobiológiai paraméterekben szignifikánsan különbözött egymástól. A talaj mikrobiológiai aktivitása, a talajban élő mikrobák mennyisége egyaránt nagyobb volt a rétként hasznosított területen. Eredményeink felhívják a figyelmet a minél hosszabb ideig tartó növényborítás biztosításának fontosságára a talaj szervesanyag-tartalmának megőrzésében, növelésében, és az ehhez szorosan kapcsolódó aktívabb talajéletfenntartásában.

A művelési ág hatása olyan erőteljes a talaj vizsgált mikrobiológiai változóira, hogy azok statisztikailag elkülönítették a szántó és rét művelési ágakat annak ellenére, hogy a korábbi mintavételi terület két-két, a területekre jellemző mikrobiális biomassza szén szélsőértéket mutató pontjaiból vettük a talajmintákat. Ugyanakkor a vizsgált kémiai, fizikai változók csoportja még nem igazolta a két művelési ág talajmintáinak statisztikai különbségét. Eredményeink tehát igazolják, hogy a talajok mikrobiológiai paraméterei gyorsabban jelezhetik a talajokban bekövetkező, esetleges negatív változásokat, mint a kémiai és/vagy fizikai paraméterek.

Open access
Acta Chromatographica
Authors: Su-su Bao, Jian Wen, Teng-hui Liu, Bo-wen Zhang, Chen-chen Wang and Guo-xin Hu

Olmutinib (Olita™) is an oral third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) which is used to treat non-small cell lung cancer (NSCLC). A simple, rapid, and sensitive method based on ultra-performance liquid chromatography tandem mass spectrometry (UHPLC–MS/MS) has been developed for the determination of olmutinib. Sample preparation was performed following simple one-step protein precipitation with acetonitrile. Olmutinib and internal standard (dasatinib) were separated on an Eclipse Plus C18 RRHD (2.1 × 50 mm, 1.8 μm) column. The mobile phase consisted of acetonitrile–0.1% formic acid in water with gradient elution. A total run time of 1.7 min was achieved. Detection was performed on a positive-ion electrospray ionization mass spectrometer in multiple reaction monitoring (MRM) mode, using transitions of m/z 487.2 → 402.1 for olmutinib and m/z 488.2 → 401 for dasatinib (IS), respectively. The calibration curve (R 2 = 0.999) was linear over the range of 1–500 ng/mL. The recovery of olmutinib ranged from 85.8% to 95.5%. This method can be applied to pharmacokinetic studies of olmutinib.

Open access

Deoxypodophyllotoxin (DPT), or anthricin, is a lignan isolated from the roots of Anthriscus sylvestris and is reported to exhibit anti-inflammatory, anti-oxidant, and anti-asthmatic effects. Herein, the conditions for the extraction of DPT from A. sylvestris are optimized using a Box–Behnken design (BBD) method based on response surface methodology (RSM). DPT was detected by ultra-performance liquid chromatography coupled with photodiode array and quadrupole detector (UPLC–PDA–QDa) and analytical validation methods based on International Conference on Harmonization (ICH) guidelines. In preliminary experiments, the experimental conditions of extraction time, solvent percentage, and temperature were selected for optimization. The adequacy of the experimental model was statistically evaluated, and the regression coefficient (R 2), adjusted regression coefficient (R 2 adjust), and p-value of the lack-of-fit were determined as 97.86%, 94.02%, and 0.124, respectively. The maximum yield of DPT was estimated to be 2.341 mg/g for 30 min in 100% methanol at 60 °C, and the actual yield was measured as 2.295 mg/g (±0.023) under the same conditions.

Open access

Wheat is a major crop, an important component of the human diet and important source of animal fodder in the world. Characterization of phenolic profiles of the leading wheat cultivars is important for new opportunities for breeding and eventual commercial production of value-added cultivars rich in beneficial components. A method using ultra-performance liquid chromatography combined with photodiode-array detector–electrospray ion source–mass spectrometry (UPLC–PDA–ESI–MS) has been developed for determination of phenolic compounds contained in twelve winter and thirteen spring wheat varieties. The antioxidant activity was determined by the thin-layer chromatography–2,2-diphenyl-1-picrylhydrazyl (TLC–DPPH) test with image processing by means of the ImageJ program. Based on retention time, the mass of deprotonated molecule [M−H] and ultraviolet (UV) spectra, seven phenolic acids, and twelve flavonoids were identified and quantitated in the 80% aqueous methanol extract of the wheat varieties. The average concentrations of total researched compounds were definitely higher in spring wheat cultivars than in winter ones. Varieties Trappe and Kandela showed the most elevated values of total free phenolic acids. Kandela and Ostka Smolicka had the highest content of flavonoids, and isoorientin was detected as the main phenolic in wheat cultivars. Additionally, a correlation between radical scavenging activity and total phenolic acids content was observed. UPLC combined with PDA–ESI–MS could be applied to complete characterization of natural products (e.g., phenolics) in alcoholic extracts from wheat varieties.

Open access

A simple, efficient, and stable high-performance liquid chromatography (HPLC) separation method for a combination of rifampicin (RIF), its major metabolite 25-O-desacetyl rifampicin (25ODESRIF), and neostigmine (NEO) was developed and validated. The drugs individually, and in combination, were analyzed using a Waters Alliance 2695 HPLC coupled with 2996 photodiode array detector (PDA). Successful separation of combined drugs was achieved by gradient elution on a reverse-phase C-18 Phenomenex Luna column, using a mobile phase consisting of water and methanol at detection wavelength of 254 nm. The HPLC retention times were consistent at ±7.70 min, ±8.25 min, and ±10.70 min for RIF, 25ODESRIF, and NEO, respectively. The regression data for the calibration plots exhibited linear relationship (R 2 = 0.995) in the range of 0–200 μM for both RIF and 25ODESRIF, and the lower limit of detection (LLOD) and lower limit of quantification (LLOQ) were calculated at 5.86 μM and 17.75 μM for RIF and 7.78 μM and 23.57 μM for 25ODESRIF, respectively. The method was evaluated using in vitro human liver microsomes (HLMs) assays, and linearity was established for the 15, 30, 45, and 60 min incubations (R 2 = 0.99). The formation of 25ODESRIF was characterized by hyperbolic kinetics (K m 48.23 μM, V max 1.233 pmol/min/mg protein, and CLint 0.026 μl/min/mg protein). The method was applied in HLM assays to understand the herb–drug interaction (HDI) potential of Althaea officinalis, a popular African herb consumed by tuberculosis (TB) patients, with RIF. None of the extracts of A. officinalis inhibited the esterase-mediated metabolism pathway of RIF, compared to the positive control nelfinavir (IC50 = 9.59 μM). The method provides a tool for quantifying RIF and 25ODESRIF in in vitro drug metabolism assays as well as investigating herb– and drug–drug interactions (DDIs).

Open access

In this study, discrimination of Chinese yellow wines from Shaoxing, Shandong, and Hubei in China has been carried out according to volatile flavor components. A total of 122 yellow wine samples were characterized by gas chromatography–ion mobility spectrometry (GC–IMS). A simple color mixing method was visually used to select characteristic peaks based on the RGB color model. Then, the volatile organic compounds corresponding to the selected characteristic peaks were identified via library searching, and the height values of those peaks were arranged for further chemometric pretreatment. Principal component analysis was employed to reveal significant differences and potential patterns between samples. Finally, quadratic discriminant analysis was applied to develop a classification model and achieved a correct classified rate of 95.35% for the prediction set. The results prove that the aroma composition combined with chemometric tools can be used as a fingerprinting technique to protect the product of origin and enable the authenticity of Chinese yellow wine.

Open access

In this study, the in vitro phase I metabolism of lacosamide was characterized with the use of ultra-high-performance liquid chromatography combined with high-resolution mass spectrometry (quadrupole time-of-flight). The use of two metabolism simulation techniques (photocatalysis and human liver microsomes) allowed the characterization of a polar metabolite of parent compound, not yet described. The experiment with the participation of HLM gave the ability to describe the full liver metabolic pathway of lacosamide. It has been proven that this molecule undergoes deacetylation, demethylation, and during liver tissue metabolism. Photocatalysis with the use of a TiO2 catalyst was proved to be a complementary technique in mimicking in vitro drug metabolism.

Open access
Acta Chromatographica
Authors: Stefano Dugheri, Nicola Mucci, Alessandro Bonari, Giorgio Marrubini, Giovanni Cappelli, Daniela Ubiali, Marcello Campagna, Manfredi Montalti and Giulio Arcangeli

Sample pretreatment is the first and the most important step of an analytical procedure. In routine analysis, liquid–liquid microextraction (LLE) is the most widely used sample pre-treatment technique, whose goal is to isolate the target analytes, provide enrichment, with cleanup to lower the chemical noise, and enhance the signal. The use of extensive volumes of hazardous organic solvents and production of large amounts of waste make LLE procedures unsuitable for modern, highly automated laboratories, expensive, and environmentally unfriendly. In the past two decades, liquid-phase microextraction (LPME) was introduced to overcome these drawbacks. Thanks to the need of only a few microliters of extraction solvent, LPME techniques have been widely adopted by the scientific community. The aim of this review is to report on the state-of-the-art LPME techniques used in gas and liquid chromatography. Attention was paid to the classification of the LPME operating modes, to the historical contextualization of LPME applications, and to the advantages of microextraction in methods respecting the value of green analytical chemistry. Technical aspects such as description of methodology selected in method development for routine use, specific variants of LPME developed for complex matrices, derivatization, and enrichment techniques are also discussed.

Open access
Acta Chromatographica
Authors: Andreea Silvia Neamţu, Andrei Biţă, Ion Romulus Scorei, Gabriela Rău, Ludovic Everard Bejenaru, Cornelia Bejenaru, Otilia-Constantina Rogoveanu, Carmen Nicoleta Oancea, Antonia Radu, Cătălina Gabriela Pisoschi, Johny Neamţu and George Dan Mogoşanu

The identification and quantitation of nicotinamide riboside (NAR) and its main related compound (nicotinamide) were achieved using high-performance thin-layer chromatography (HPTLC)–ultraviolet (UV) densitometry with confirmation by online electrospray ionization (ESI)–mass spectrometry (MS). As the stationary phase, HPTLC Si 60 F254 glass plates were employed; the mobile phase was ethanol–1 M ammonium acetate–formic acid (7:1:0.1, v/v/v). No derivatization was applied, and UV densitometry was performed in the absorbance mode (270 nm). The method was validated by specificity, linearity, accuracy, precision, and robustness.

Open access

Hair is a stable specimen and has a longer detection window (from weeks to months) than blood and urine. Through the analysis of hair, the long-term information of the drug use of the identified person could be explored. Our work is to establish an ultra-performance liquid chromatography–tandem mass spectroscopy (UPLC–MS/MS) method for simultaneous determination of methamphetamine, amphetamine, morphine, monoacetylmorphine, ketamine, norketamine, 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyamphetamine (MDA) in hair. Methoxyphenamine was used as an internal standard. The chromatographic separation was performed on a UPLC ethylene bridged hybrid (BEH) C18 (2.1 mm × 50 mm, 1.7 μm) column using a mobile phase of acetonitrile–water with 10 mmol/L ammonium acetate solution which containing 0.05% ammonium hydroxide. The multiple reaction monitoring in positive electrospray ionization was used for quantitative determination. The intra-day and inter-day precisions (relative standard deviation [RSD]) were below 15%. The accuracy ranged between 85.5% and 110.4%, the average recovery rate was above 72.9%, and the matrix effect ranged between 92.7% and 109.2%. Standard curves were in the range of 0.05–5.0 ng/mg, and the correlation coefficients were greater than 0.995. The established UPLC–MS/MS method was applied to analyze the hair samples successfully.

Open access
Acta Chromatographica
Authors: Milica Atanacković Krstonošić, Jelena Cvejić Hogervorst, Mira Mikulić and Ljiljana Gojković-Bukarica

Phenolic compounds are frequently present in various natural products, and they can have different beneficial biological potentials. The most widely used method for determination of individual phenolic compounds is high-performance liquid chromatography (HPLC). In this paper, a method for simultaneous determination of 16 phenolic compounds (gallic acid, p-hydroxybenzoic acid, catechin, syringic acid, trans-cinnamic acid, hesperetin, naringenin, vanillic acid, benzoic acid, coumaric acid, resveratrol, chlorogenic acid, caffeic acid, rutin, quercetin, and kaempferol) on a core–shell column was developed. The separation method conducted on a standard ODS (250 mm) column was transferred to Poroshell column and optimized using non-ultra-high-performance liquid chromatography (UHPLC) apparatus. Phenolic compounds were separated fast and efficiently during 30-min analysis, and validation parameters were determined. The developed method was successfully applied on the analysis of phenolic content after direct injection of red wines from three different grape varieties.

Open access

A sensitive, stability-indicating reversed-phase high-performance liquid chromatography with diode array detection (HPLC–DAD) method has been developed for the determination of TBI-166 and its 10 kinds of related impurities. Chromatographic separation was achieved on a Kromasil ODS column (250 mm × 4.6 mm, 5 μm), with a gradient elution of the mobile phase system consisting of acetonitrile and 1% ammonium formate solution (with 0.2% formic acid). The flow rate was 1.0 mL/min, and the detection wavelength was set at 251 nm. The method was validated according to the International Conference on Harmonization (ICH) guidelines with respect to selectivity, linearity, limits, accuracy, precision, and robustness. The calibration curves were linear from LOQ to 150% of the specification limit of impurity with correlation coefficients not less than 0.999. The limits of quantitation were between 0.123 and 0.257 μg/mL. Accuracy for the related substances was estimated by the recovery ranged from 94.6% to 111.2%. The method was proved to be reliable for the determination of related substances in TBI-166 bulk drug, which is essential and important in the quality control.

Open access

Two sensitive and selective chromatographic methods were developed for determination of finasteride and tamsulosin hydrochloride in bulk powder and a pharmaceutical formulation. The first method was based on high-performance liquid chromatography (HPLC) separation of the cited drugs in the presence of the acid degradation product of finasteride. The separation was achieved using a C18 column (300 mm × 3.9 mm; 10-μm particle size) and a mobile phase consisting of 0.04 M ortho-phosphoric acid (pH 3.5 ± 0.2 adjusted with triethylamine) and acetonitrile (50:50, v/v). Quantification was achieved with ultraviolet (UV) detection at 215 nm. Linearity was in the range of 10.00–110.00 μg/mL and 2.00–44.00 μg/mL for finasteride and tamsulosin hydrochloride, respectively. Thin-layer chromatography (TLC)–densitometric method was achieved on an aluminum plates pre-coated with silica gel 60 F254 using toluene–ethanol–diethylamine (8:2:1.5, by volume) as eluent, and the R F values of tamsulosin hydrochloride and finasteride were 0.57 and 0.64, respectively. Quantification was achieved with UV detection at 250 nm for finasteride and 280 nm for tamsulosin hydrochloride. Linearity was in the range of 1.00–40.00 and 0.2.00–20.00 μg per spot for finasteride and tamsulosin hydrochloride, respectively. The results obtained were validated according to the International Conference on Harmonisation (ICH) guidelines. A statistical comparison between the obtained results and the results of a reported method was carried out.

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The levels of persistent organic pollutants, polychlorinated biphenyls (PCBs), were determined in seawater and marine sediments from different sites along the Jordanian coast of the Gulf of Aqaba. Concentrations of 7 PCBs, namely, PCB-28, PCB-52, PCB-101, PCB-118, PCB-138, PCB-153, and PCB-180, were determined. An automated Soxhlet (Soxtec) extraction method was used for extraction with hexane–acetone as a solvent, and a pre-washed multilayer silica gel column was used for the clean-up step. Samples were analyzed using capillary gas chromatography (GC) with an electron capture detector (ECD) and GC–mass spectrometry (GC–MS) for confirmation. The method's limits of detection (LOD) were determined to be from 0.40 to 1.53 ng/L and from 0.39 to 0.91 ng/g dry weight for seawater and sediment, respectively. Concentrations of PCBs in seawater and sediment samples from all sites were below the LOD. This study provides evidence that very low concentrations of PCBs (<2 ng/g) were found in the water and sediments of the Jordanian coast of the Gulf of Aqaba. PCB concentrations measured in this study can be considered as a baseline for future monitoring and control of PCBs as requested by the Stockholm Convention.

Open access
Acta Chromatographica
Authors: Feng Wu, Xiuli Zhao, Shumin Wang, Hui Zhou, Shaojie Guo, Siyang Ni, Bo Yang, Lihua Zhang and Xinde Xu

The aim of this study was to develop and validate a HPLC-MS/MS assay to determine the lutein concentration in plasma samples of human and SD rats. Organic solvent was used for lutein extraction. The extract was injected into a HPLC-MS/MS system. Reversed phase chromatography was performed on a C18 column in gradient mode. Lutein and internal standard (phenytoin sodium) were identified in atmospheric pressure chemical ionization mode using ion transitions of m/z 567.5>549.4 and 205.2>110.8, respectively. The lutein quantification assay was linear over concentrations ranging from 4 to 500 ng/mL. The lower limit of quantification was 4 ng/mL with satisfactory precision and accuracy. The assay presented acceptable intra and inter-batch precision (RSD%) and accuracy (RE%) <8.16% in SD rat plasma and <12.80% in human plasma. The extraction recovery ranged from 50.94 to 60.90% in SD rat plasma and 68.73% in human plasma. The matrix effect for lutein was acceptable and had minimal influence on the results. The method was then applied to determine the lutein concentrations in human plasma after a single oral dose of 20mg lutein. The method described is rapid, selective, sensitive and reproducible. This method can be used for both pharmacokinetic studies and therapeutic drug monitoring purposes.

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A new and sensitive method, termed magnetic solid phase extraction combined with dispersive liquid–liquid microextracton (MSPE–DLLME), has been developed for the simultaneous determination of biphenyl and biphenyl oxide in water samples. Different parameters influencing the extraction efficiency, including the amount of sorbent, sorption time, type of elution solvent and its volume, type of extraction solvent and its volume, and elution time were optimized. The calibration curves were linear in the range of 0.5–100 μg/L for both of them. The limits of detection (LODs) were achieved, 0.03 μg/L for biphenyl and 0.07 μg/L for biphenyl oxide, respectively. Ultimately, the applicability of the method was successfully confirmed by the extraction and determination of biphenyl and biphenyl oxide in sea, river, tap, and water well.

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The essential oils isolated by hydrodistillation from Thymus pallescens de Noé dried leaves exposed to γ-irradiation at dose levels of 0, 5, 10, 20, and 30 kGy were analyzed by gas chromatography–flame ionization detector (GC–FID) and GC–mass spectrometry (MS) and tested for their antioxidant, antimicrobial, and insecticidal activities. No qualitative change was observed in the chemical composition. Carvacrol (81.8–85.7%) was the most prominent component. Gamma-irradiation at 20 kGy affects quantitatively some components. Antioxidant activity was evaluated by four different test systems, namely, inhibition of lipid peroxidation (thiobarbituric acid reactive substance, TBARS), ferric reducing power, and scavenging of radicals DPPH and ABTS•+. In all systems, irradiated oils at 20 and/or 30 kGy showed the most antioxidant efficiency. Overall, the antimicrobial activity conducted against seven microorganisms revealed no significant changes according to the radiation dose. Fumigation bioassays and contact method against confused flour beetle Tribolium confusum revealed that the oil irradiated at 20 kGy had highest insecticidal activity. The results showed that gamma-irradiation of T. pallescens could be not only beneficial safe decontamination perspective but also as an improvement factor of some of its properties.

Open access

Method for the analysis of intracellular adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP) in Mycobacterium smegmatis that involves rapid extraction procedure based on sonication of cells in perchloric acid, as well as separation of nucleotides by ion-pair reversed-phase high-performance liquid chromatography and ultraviolet (UV) detection at 254 nm, is developed. The analytes were separated with mobile phase consisted of acetonitrile and 50 mM monobasic potassium phosphate (pH 4.6) with 25 mM tetrabutylammonium hydrogensulfate in a ratio of 0.5:99.5% within 30 min. The calibration curves were linear in the range of 20–1000 pmol of ATP and 10–1000 pmol of ADP and AMP with correlation coefficient (r ) of ≥0.9998. The proposed method is applicable for mycobacterium cultures taken over a wide range of optical density and physiological states. Concentrations of ATP, ADP, and AMP in mycobacterial extracts varied from 2.61 ± 0.27 to 9.60 ± 0.19 nmol/mg dry weight, from 1.75 ± 0.12 to 5.86 ± 0.09 nmol/mg dry weight, and from 0.55 ± 0.08 to 4.40 ± 0.07 nmol/mg dry weight, respectively, depending on the physiological state.

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Lacosamide, a new type of antiepileptic drug, was subjected to forced degradation under the conditions of hydrolysis (acidic and alkaline), oxidation, dry heat, and photolysis to characterize its possible degradation products. The drug showed significant degradation under acidic, alkaline and oxidative conditions. The degradation products were separated on an Agilent Zorbax SB-C18 column with gradient elution using a mobile phase consisting of acetonitrile and ammonium acetate (0.002 mol/L) with formic acid as additive. A combination of liquid chromatography hybrid triple quadrupole-linear ion trap mass spectrometry (LC–QqLIT-MS) and liquid chromatography hybrid ion trap/time-of-flight mass spectrometry (LC-IT/TOF-MS) was used to identify degradation products. A total of 7 products including 4 novel degradation products were characterized. The mechanisms of degradation products of lacosamide were discussed. Application of the method to study degradation products of lacosamide provided fragment information, allowing further investigation of the degradation pathways and intrinsic stability of the drug.

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A new reliable simple solvent extraction method for the endocrine disruptor bisphenol A (BPA) in canned food was developed employing an aqueous basic extraction solution of 0.25 M K2CO3/0.10 M NaOH after spiking with BPA-d16 as internal standard. The BPA was next extracted into diethyl ether after solution acidification to pH = 4 and filtration. Homogenous acetylation at dry basic conditions (acetic anhydride as derivatization agent and solvent with sodium acetate as catalyst) after diethyl ether evaporation was carried out for 30 min at 110 °C. Detection of the acetylated BPA was carried out by gas chromatography–electrospray ionization/mass spectrometry (GC–EI/MS) in the selected ion monitoring (SIM) mode with pulsed split-less mode. The method was applicable in terms of eliminating the use of solvents like acetonitrile for the extraction step, where relatively long evaporation times may have been needed to evaporate acetonitrile. Also, removing lipids and precipitating most of the proteins at acidic conditions (pH = 4) prior to diethyl ether extraction can replace the often used heptane or hexane or solid sorbents. The method was tested linear with limit of linearity (LOL = 750 μg/L) and with coefficient of determination (R = 0.998), repeatable with relative standard deviation (RSDr < 7%) with instrument detection limit (IDL) of 0.01 μg/L and limit of quantitation (LOQ) of 0.034 μg/L. The method detection limit (MDL) ranged from 0.3 μg/kg to 3.2 μg/kg based on 1 g sample (wet weight). Recovery ranged from 85% to 94% with the relative standard deviations of 2%–13%. BPA concentrations in tested canned foods from outlet stores ranged from <MDL to 57.4 ± (2.6) μg/kg which were below the specific limit for BPA migration in food proposed by the European Union (EU) and within the food safety and quality criteria. The extraction and derivatization steps for BPA were unique and have not been reported in literature.

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Seven compounds, including two flavanones, dihydrokaempferol (1) and naringenin (2), and five terpenoids, boscartol A (3), 3,7-dioxo-tirucalla-8,24-dien-21-oic acid (4), 3α-acetoxyl-7-oxo-tirucalla-8,24-dien-21-oic acid (5), 11-keto-β-boswellic acid (6), and acetyl-11-keto-boswellic acid (7), have been purified by high-speed counter-current chromatography (HSCCC) from olibanum. For the separation, from 250 mg of the crude extract, 3.1 mg of 1 (95.2% purity), 2.7 mg of 2 (96.1% purity), 9.1 mg of 3 (96.7% purity), 4.5 mg of 4 (95.3% purity), 5.4 mg of 5 (96.3% purity), 48.1 mg of 6 (96.8% purity), and 45.5 mg of 7 (98.1% purity) were obtained by HSCCC with petroleum ether–ethyl acetate–methanol–water (1:0.8:1.1:0.6, v/v). The structures of these seven compounds were elucidated by a combination of electrospray ionization mass spectrometry (ESI–MS) and extensive nuclear magnetic resonance (NMR) spectroscopic.

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A residue analytical method was developed for the determination of trichlorfon, chlorpyrifos, dimethoate, β cypermethrin, deltamethrin, and chlorothalonilin in six leafy vegetables by gas chromatography–electron capture detector (GC–ECD) and gas chromatography–flame photometric detector (GC–FPD). The method had a good linearity (R 2 ≥ 0.9924) and precision (RSD ≤ 14.0%). The limits of quantification (LOQ) of six pesticides were all 0.01 mg/kg. Average recoveries of six pesticides ranged from 81% to 119%. The developed method was successfully applied to study the initial deposits, degrade characteristics, and terminal residues for six pesticides applied to six leafy vegetables under the same dose of formulation. The half-life of six pesticides was in the range of 0.8–8.8 days. The highest initial deposits, maximal residues, and terminal residues were found on leaf mustard and sweet potato leaves as the same pesticides were applied in different crops. Therefore, leaf mustard can be selected as representative commodity in the same subgroup to realize the residual extrapolation. This conclusion should be considered as a complement on crop classification of China.

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Atractylodis exerted a variety of pharmacological effects such as anti-tumor, anti-inflammatory, anti-bacterial, and anti-aging effects etc. The major ingredients of Atractylodis are atractylenolide I and II that exhibited activities in anti-inflammatory and anticancer. In this work, a sensitive and selective ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method for determination of atractylenolide I and II in rat plasma was developed. The UPLC–MS/MS method was validated for selectivity, linearity, accuracy, precision, recovery, and stability with a total run time of 4.0 min. After addition of atractylenolide III as an internal standard (IS), protein precipitation by acetonitrile was used to prepare samples. Chromatographic separation was achieved on a UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) with 0.1% formic acid and acetonitrile as the mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; multiple reactions monitoring (MRM) mode was used for quantification using target fragment ions m/z 231.1 → 185.1 for atractylenolide I, m/z 233.1 → 91.0 for II, and m/z 249.0 → 231.1 for IS. Calibration plots were linear throughout the range 1–1000 ng/mL for atractylenolide I and II in rat plasma. Mean recoveries of atractylenolide I and II in rat plasma ranged from 86.2% to 96.3%. Relative standard deviation (RSD) of intra-day and inter-day precision was both less than 12%. The accuracy of the method was between 91.0% and 109.0%. The method was successfully applied to pharmacokinetic study of atractylenolide I and II after intravenous administration in rats.

Open access

You-Gui-Yin (YGY), a famous traditional Chinese medicine, has been widely used in clinics for the treatment of kidney-yang deficiency, yang deficiency caused by excessive yin, and osteoporosis. A rapid and sensitive ultraperformance liquid chromatography–electrospray ionization–mass spectrometry (UPLC–ESI–MS) method for simultaneous determination of six Aconitum alkaloids including aconitine (AC), hypaconitine (HA), mesaconitine (MA), benzoylaconine (BAC), benzoylhypaconine (BHA), and benzoylmesaconine (BMA) in rat plasma after oral administration of YGY was developed in this study. Chromatographic separation was performed on an ACQUITY UPLC™ BEH C18 column (2.1 × 100 mm, 1.7 μm) using gradient elution with the mobile phase consisting of 2 mmol/L ammonium formate in 0.05% formic acid aqueous solution and 0.05% formic acid methanol solution, at a flow rate of 0.20 mL/min. MS detection was performed in the positive ion mode. The calibration curves were linear in the concentration range of 0.04160–41.60 ng/mL, 0.1070–107.0 ng/mL, 0.07358–73.50 ng/mL, 0.03228–32.28 ng/mL, 0.01809–18.09 ng/mL, and 0.1320–132.0 ng/mL for AC, HA, MA, BAC, BHA, and BMA, respectively. The intra- and inter-day precisions (relative standard deviation [RSD]) were less than 11.6% and 12.6%, respectively. The accuracies Relative Error (RE) ranged from −10.2% to 5.6%, while the recoveries ranged from 70.4% to 99.3%. The method for simultaneous quantitation of Aconitum alkaloids of You-Gui-Yin in rat plasma is accurate and repeatable, and this method was successfully applied to investigate the pharmacokinetics of the six Aconitum alkaloids in rat plasma after oral administration of YGY. For the pharmacokinetic study, the pharmacokinetics of the six Aconitum alkaloids were best described by a two-compartment open model.

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2′,4′,6′,4-Tetra-O-acetylphloretin (TAPHL) is a prodrug of phloretin (PHL) in which the OH groups are protected by acetylation. A validated liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for the determination of PHL in rat biological matrices was developed and applied to investigate and compare the pharmacokinetics, tissue distribution, and excretion of PHL and TAPHL in rats following a single oral administration. The method was validated for accuracy, precision, linearity, range, selectivity, lower limit of quantification (LLOQ), recovery, and matrix effect. All validation parameters met the acceptance criteria according to regulatory guidelines. The mean pharmacokinetic parameters of t max, C max, AUC(0 − t), CL/F, and t 1/2 were observed after oral administration in rats. The data showed that PHL was absorbed and eliminated rapidly from plasma after oral administration. The pharmacokinetic properties are improved, such as the t max has been prolonged and the area under the curve (AUC) has been enhanced after oral administration of TAPHL to rats. Tissue distribution results indicated that PHL could be rapidly and widely distributed into tissues but could not effectively cross the blood–brain barrier in rats. After oral administration of TAPHL to rats, its tissue distribution to rats was similar as that after oral administration of equimolar PHL. In addition, higher recoveries of PHL following administration of TAPHL indicated that TAPHL might reduce the excretion of PHL from the body by reducing the first pass effect.

Open access

The aim of this work was to simultaneously separate, identify, and characterize all the degradation products (DPs) of atorvastatin (AT) and olmesartan (OM) formed under different stress conditions as per International Conference on Harmonization (ICH) Q1A(R2) guideline. AT showed labile behavior in acidic, basic, neutral, and oxidative stress and led to the formation of two DPs, while OM degraded under acidic, basic, and neutral and resulted in the formation of four DPs. All the stressed samples of AT and OM were resolved on a C-18 column in single run on a gradient liquid chromatographic (LC) mode. A complete mass fragmentation pathway of both the drugs was established with the help of tandem mass spectrometry (MS/MS) studies. The fragmentation was further supported by MSn studies, and for AT, it was carried out up to MS6, while for OM, it was up to MS5. Then, the stressed samples were analyzed by LC–MS/MS to get the fragmentation patterns of DPs. LC–MS/MS data helped to propose chemical structure of all the DPs. Based on this entire information, degradation pathway of both the drugs was established. The developed method has shown excellent linearity over the range of 10 to 150 μg/mL of OM and AT. The correlation coefficient (r 2) for OM and AT is 0.999 and 0.998, respectively. The main recovery value of OM and AT ranged from 99.97% to 100.54%, while the limit of detection (LOD) for OM and AT was 0.018 and 0.021 μg/mL, and limit of quantitation (LOQ) was found to be 0.051 and 0.063 μg/mL. Finally, the in-silico carcinogenicity, mutagenicity, and hepatotoxicity predictions of AT, OM, and all the DPs were performed by using toxicity prediction softwares, viz., TOPKAT, LAZAR, and Discovery Studio ADMET, respectively.

Open access
Acta Chromatographica
Authors: Filip Šibul, Dejan Orčić, Sanja Berežni, Goran Anačkov and Neda Mimica-Dukić

Scentless chamomile (Tripleurospermum inodorum = M. inodora) is a plant belonging to Anthemideae tribe of Asteraceae family, with phenotype similar to the common chamomile, a plant used in human consumption in the form of herbal tea infusion. In order to be able to understand possible health-promoting properties and adverse effects of the scentless chamomile's consumption, it is of essence to examine its chemical composition. The aim of the study was to perform phenolic profiling using high-performance liquid chromatography–tandem mass spectroscopy (HPLC–MS/MS), in comparison to the common chamomile. In the investigated extracts, qualitative and quantitative analyses enabled the identification of 66 compounds based on their retention times, mass (MS/MS) spectra, and analysis of their characteristic fragmentation patterns in MS/MS Product Ion Scan experiments. A new HPLC–MS/MS method for quantitation of common plant metabolites was hereby developed, enabling quantitation of 47 compounds. All examined M. inodora samples have relatively high combined phenolic and flavonoid contents (25.2–51.9 mg/g). Apigenin, apigenin-7-O-glucoside, luteolin, luteolin-7-O-glucoside, quinic acid, and 5-O-caffeoyl quinic acid were the compounds with highest concentration in both inodorous and common chamomile. The results obtained hereby represent the first and most detailed chemical profile of scentless chamomile so far.

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The specific aim of this investigation was to study the kinetics of the degradation of cefazolin, cefaclor, cefuroxime axetil, and cefepime in aqueous solution, in the presence (or absence) of various redox agents (iodine solution, potassium permanganate, hydrogen peroxide, sodium thiosulfate, and ascorbic acid) as a function of temperature. Various factors, such as concentration of the analyzed compounds and redox agents, storage time, and temperature, were analyzed. The degradation process of chosen antibiotics was observed chromatographically and fitted to the kinetic models, obtaining model parameters (k, t 0.1, t 0.5). Principal component analysis (PCA), parallel factor analysis (PARAFAC), and hierarchical cluster analysis (HCA) methods were carried out to interpret the dependencies between these factors on the drug stability.

Open access

Eight compounds were isolated and identified from the soil-inhabiting fungus Aspergillus fumigatus 3T-EGY, namely, stearic acid (1), α-linolenic acid (2), physcion (3), di-(2-ethylhexyl) phthalate (4), 2,4,5,17-tetramethoxy pradimicin lactone (5), 3,5-dihydroxy-7-O-α-rhamnopyranoyl-2H-chromen-2-one (6), juglanthraquinone A-5-O-d-rhodosamine-(4′→1″)-2-deoxy-d-glucose (4″→1″′)-cinerulose B (7), and micropeptin (8). Their structures were determined on the basis of one-dimensional (1D-) and two-dimensional nuclear magnetic resonance (2D-NMR) [1H-, 13C-NMR, 1H-1H COSY (COrrelated SpectroscopY), and 1H-13C HMBC (Heteronuclear Multiple Bond Correlation) spectroscopy]. Compound 7 showed moderate in vitro antimicrobial activity against three pathogenic strains with inhibition zones values were ranged from 9.0 to 10.66 mm compared to neomycin as a positive control with inhibition zones values were ranged from 14.0 to 19.0 mm.

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A new high-performance liquid chromatographic (HPLC) method for determination of triclosan (TCS) and flurbiprofen (FBP) was successfully developed and validated at a single wavelength. The method involves extraction of the targeted drugs from nanogels and simulated saliva by using methanol as the extractant. The Agilent ZORBAX SB-C18 column (5 μm, 4.6 × 250 mm) was used for the chromatographic separations. The effects of various parameters were extensively evaluated and optimized. The optimal HPLC conditions were acetonitrile and 0.001 M citric acid (90:10, v/v) with a pH of 3.24 as the mobile phase, at a 0.3 mL/min flow rate under isocratic elution mode. Excellent sensitivity and specificity were achieved by ultraviolet (UV) detection at 242 nm. The method also demonstrated excellent linearity within the test range of 10–100 μg/mL with the correlation coefficient (R 2) of 0.9998 for both the analytes. The practical applicability of the method was demonstrated by recovering TCS and FBP from nanogels and simulated saliva. The recovery of the analytes from the nanogels and the spiked simulated saliva samples was in the range of 97–98% and 96–99%, respectively, and their respective relative standard deviation (RSD) was less than 0.9% in both cases. System suitability parameters were found to be within acceptable limits. The method is simple, specific, and precise, and to the best of our knowledge, it is the first reported validated quantitative HPLC method for the concurrent determination of TCS and FBP in a pharmaceutical dental product. The method can be useful in the routine quality control analysis of dental formulations with TCS and FBP contents or products with a similar composition.

Open access

This study presents the development and validation of a new reversed-phase high-performance liquid chromatography (RP-HPLC) method for simultaneous determination of captan, folpet, and metalaxyl residues in table grape samples with ultraviolet–diode array detection (UV–DAD). Successful separation and quantitative determination of analytes was carried out on LiChrospher 60 RP-select B (250 × 4 mm, 5 μm) analytical column. Mixture of acetonitrile–0.1% formic acid in water (65:35, v/v) was used as a mobile phase, with flow rate of 1 mL/min, constant column temperature at 25 °C, and UV detection at 220 nm. The target residues were extracted with acetone by ultrasonication, followed by a cleanup using liquid–liquid extraction (LLE) and solid-phase extraction (SPE). The obtained values for multiple correlation coefficients (R 2 > 0.90), relative standard deviation (RSD) of retention times, peak areas and heights (RSD ≤ 2.25%), and recoveries ranging from 90.55% to 105.40%, with RSD of 0.02% to 5.37%, revealed that the developed method has a good linearity, precision, and accuracy for all analytes. Hence, it is suitable for routine determination of investigated fungicides in table grape samples.

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Eupatilin, mainly derived from Artemisia asiatica (Asteraceae), is an O-methylated flavone with various bioactivities. In the present study, a validated ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method was established for the quantification of eupatilin in rat plasma with the internal standard (IS) of tussilagone and the protein precipitation of plasma samples was performed using acetonitrile–methanol (9:1, v/v). The eupatilin and IS were eluted separately on a UPLC BEH C18 column (2.1 mm × 100 mm, 1.7 μm) with the gradient mobile phase consisted of 0.1% formic acid and acetonitrile. The protonated analytes were quantified by multiple reactions monitoring (MRM) mode with an electrospray ionization (ESI) source operated in positive ion mode. The calibration plots were found to be linear over the range from 2 to 1000 ng/mL for eupatilin in rat plasma. Both of the intra-day and inter-day precision variations (RSDs) were ≤13%. The recoveries of eupatilin in rat plasma were between 83.7% and 94.6%, and the accuracy of the method ranged from 95.8% to 107.6%. In addition, the validated method was applied to pharmacokinetic study of eupatilin after an intravenous dose of 2 mg/kg to rats.

Open access

A model process, previously developed in a series of studies, allows for the transfer of thin-layer chromatography (TLC) methods for qualitative screening of counterfeit drug products published in the Global Pharma Health Fund (GPHF) Minilab manual and US Food and Drug Administration (FDA) Compendium of Unofficial Methods for Screening of Pharmaceuticals by TLC to quantitative high-performance TLC (HPTLC)–densitometry methods. This article describes HPTLC–densitometry methods developed and validated according to this model process for pharmaceutical products of amiodarone HCl, carvedilol, doxylamine succinate, magnesium salicylate, metoprolol succinate, nebivolol HCl, and salicylamide, for which qualitative screening methods have not been published in the Minilab manual or FDA Compendium. These methods use relatively inexpensive and nontoxic “green solvents” for sample and standard solution and mobile phase preparation, Merck Premium Purity silica gel 60 F254 plates, automated standard and sample solution bandwise application, and automated densitometry for the assessment of peak purity and identity and quantification. Corresponding to the quantitative HPTLC–densitometry methods, qualitative TLC screening methods for these drug products were developed and posted online with open access as supplements to the FDA Compendium.

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A specific, very rapid, and sensitive ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method for quantitative analysis of curcumin in human plasma has been developed and validated. Diazepam was used as internal standard (IS). The analytes were isolated using liquid–liquid extraction method with the mixture of ethyl acetate–methanol (95:5). The organic solvents were evaporated, reconstituted in mobile phase, and injected to UPLC completed with UPLC BEH C18 column 1.7 μm, 2.1 × 100 mm Acquity® Waters as stationary phase, mixture of 0.15% formic acid–acetonitril (50:50, v/v) as mobile phase, and flow rate of 0.5 mL/min and detected in positive ionization mode tandem mass spectrometer operated in multiple reaction monitoring (MRM). The MS/MS ion transitions monitored were m/z 369.05 → 176.95 and 284.95 → 193 for curcumin and IS, respectively. The retention times for curcumin and IS were 1.7 and 1.4 min, respectively, and the linearity range was 1–100 ng/mL with a coefficient correlation (r) of 0.999 and lower limit of quantitation (LLOQ) of 1 ng/mL. The relative standard deviation (RSD) values of the intra- and inter-assay precisions of the method were below 8.3% and 12.7%, respectively, while the accuracy ranged from 89.5 to 98.7% and the extraction recovery of curcumin and IS was up to 86.6%. The data presented show that the method provides specific, very rapid, sensitive, precise, and accurate measurements of curcumin concentrations in human plasma.

Open access

The aim of this study was to identify and determine by means of gas chromatography–flame ionization detector (GC–FID) and gas chromatography–mass spectrometry (GC–MS) method the volatile compounds of essential oils obtained from three varieties of narrow-leaved lavender grown in the field and in in vitro cultures. The essential oils were isolated by hydrodistillation in Deryng apparatus. It was found that the analyzed essential oils varied in terms of chemical composition depending on the variety and conditions of growth. Sixty-four to 87 different compounds were identified in the oils. Essential oils of all 3 varieties obtained in in vitro cultures contained large amounts of borneol (13–32%). This compound was also dominant in plants obtained from in vivo conditions in varieties Ellagance Purple (11%) and Blue River (13%), and in the Munstead variety, the dominant compound was linalool (13%). High concentration of epi-α-cadinol (10–20%) was found in essential oils obtained from in vitro cultured plants. Globulol was found in high concentration (10%) in the Munstead variety grown in in vitro conditions. However, significant quantitative and qualitative differences were found with respect to composition of essential oils obtained from plants grown in the field and in vitro conditions. There was a lack of (E)-β-ocimene, 3-octyn-2-one, 1-octen-3-yl acetate, sabina ketone, pinocarvone, trans-carveol, nerol, epi-longipinanol, or humulene epoxide II. In comparison to oils obtained from field-grown plants, the oils isolated from plants grown in in vitro conditions contained the less volatile compounds identified in the final stage of GC–FID and GC–MS analysis, i.e., thymol, carvacrol, γ-gurjunene, trans-calamene, α-calacorene, khusinol, and 8-cedren-13-ol.

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In this reported study, a direct high-performance thin-layer chromatographic (HPTLC) method was developed to qualitatively detect and quantitatively determine glycerol in Antarctic krill for the first time. This procedure was based on the extraction of glycerol by ultrasonic solvent extraction with anhydrous ethanol, silica-gel column chromatographic separation, HPTLC detection and quantification using methylene chloride–methanol (5:1, v/v) as the developing solvent and alkaline potassium permanganate as chromogenic agent. The content of glycerol was 1.3725 ± 0.218 mg/g in freeze-dried Antarctic krill. The structure of glycerol in the Antarctic krill was subsequently determined by gas chromatography–mass spectrometry (GC–MS) which verified the presence of the material in the krill. The HPTLC method exhibited excellent accuracy with a recovery of 90.1–103.3% and good precision with a relative standard deviation (RSD) of 1.59–4.84%. The results clearly exhibited the applicability of the proposed for quantifying glycerol in Antarctic krill.

Open access

Agaricus bisporus and Imleria in vitro cultures were cultivated on modified Oddoux medium, and Oddoux medium was enriched with serine or anthranilic acid. Serine or anthranilic acid was used at the concentrations of 0.1, 0.25, 0.5, and 0.75 g/L of medium. Determination of indole compounds in the obtained biomass was carried out using thin-layer chromatography (TLC) with densitometric detection. In every analyzed sample, presence of serine or anthranilic acid was studied. Comparison of the results obtained for the treatment and control samples allowed us to determine the optimum concentration of serine or anthranilic acid in the medium in order to obtain biomass with increased content of indole compounds. A. bisporus with addition of anthranilic acid or serine to the medium at the concentration of 0.5 g/L was the most beneficial. In the case of Imleria badia, anthranilic acid at the concentration of 0.5 g/L was the most optimal. This is the first report demonstrating the content of indole derivatives in biomass affected by their precursors (serine or anthranilic acid). The study indicates that modification of the medium can provide satisfactory results, and it is worth to search for its new, improved compositions.

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A validated high-performance liquid chromatography (HPLC) method has been developed to analyze the (±)-gossypol in the selection of strains of Candida tropicalis culture. Since gossypol was easily degraded and oxidized, the addition of antioxidant NADPH-Na4 and acetone extraction was chosen to prevent gossypol degradation and gradient elution assay was applied to obtain gossypol resolution. Concentrations of gossypol in C. tropicalis ZD-3 culture 20 μg/mL were determined, and concentration–time profiles were observed. Linearity of the gossypol standard curve by HPLC area method was ranged from 0.1 to 20 μg/mL with Y = 26.954 × X − 29.547, R 2 = 0.9991, and n = 3, with limit of detection (LOD) of 50 ng/mL and lower limit of quantification (LLOQ) of 500 ng/mL. The recovery rate is dose-dependent and ranged from 85.3% to 103.5%. It is a rapid and reliable HPLC method for gossypol quantization in microorganism culture which could be applied in solid fermentation in the feed industry.

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Stability-indicating High-Performance Thin-Layer Chromatography (HPTLC) method for simultaneous estimation of cefixime trihydrate and azithromycin dihydrate was developed. Both the drugs were subjected to different stress conditions recommended by International Conference on Harmonization (ICH) guideline Q1A (R2). Forced degradation was carried out for hydrolytic, oxidative, photolytic, and thermal degradation conditions. Cefixime was susceptible for degradation under all stress conditions showing four degradation products (CI–IV). However, azithromycin formed only one degradation product (AI) under acid hydrolysis. Aluminum plates precoated with silica gel 60F254 were used as the stationary phase while mixture of ethyl acetate–methanol–acetone–toluene–ammonia (1:5:7:0.5:0.5, v/v) was used as mobile phase. Detection wavelength used was 235 nm for CEFI and CI–IV. AZI and AI were detected by post development derivatization, spraying with sulfuric acid–ethanol (1:4, v/v) followed by heating at 100 °C for 5 min. Degradation products were isolated by preparative HPTLC and characterized by MS/MS. The developed method was validated for linearity, precision, accuracy, specificity, and robustness and has been successfully applied in the analysis of these drugs in tablet dosage form.

Open access

Herbal products, which comprise a wide variety of bioactive molecules, have been used as remedies for different diseases throughout history. Lagenaria siceraria, a fruit vegetable, is employed in folk medicine as a treatment for various disorders including diabetes, hyperlipidemia, and heart and liver ailments. In the present work, a number of compounds were isolated and characterized from the ethyl acetate fraction of the methanolic extract of its peel, including β-sitosterol, vanillin, quercetin, rutin, 3-tert-butyl-4-hydroxyanisole, stearic acid, 2,4-bis(1,1-dimethylethyl)phenol, 2,2′-methylenebis[6-(1,1-dimethylethyl)-4-methylphenol], 1,2-benzenedicarboxylic acid mono(2-ethylhexyl) ester, hexadecanoic acid and its methyl ester, (Z,Z)-9,12-ocatdecadienoic acid and its ester, and (Z,Z,Z)-9,12,15-ocatdecatrienoic acid methyl ester. Separation of the phytochemicals was done using column and thin-layer chromatography, while gas chromatography–mass spectrometry (GC–MS), liquid chromatography-mass spectrometry (LC–MS), and high-performance liquid chromatography (HPLC) were employed for their identification. These compounds are being reported for the first time from the peel of the fruit of L. siceraria. The results provide a possible chemical rationale for the medicinal applications of this fruit.

Open access
Acta Chromatographica
Authors: Yun Zhou, Guifeng Huang, Xiaolan Li, Feng Chen, Hong Liu, Ying Yang, Zhong Fan, Jinghui Jiang and Jun Yang

A credible method for determination of the aglycon moieties of glycosidically bound aroma compounds in Flos Chrysanthemi by comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC × GC–TOFMS) has been proposed. The aglycon moieties of glycosidically bound aroma compounds were isolated using methyl-tert-butyl ether (MTBE) extraction following enzymatic hydrolysis. The GC × GC–TOFMS analysis was performed to comprehensively identify different forms of the released aroma components in Flos Chrysanthemi. The result shows that the limit of detection of the released aglycon moieties ranged from 0.3 to 3.1 ng/mL, the recovery of the released 1-octanol was better than 98.3%, and the intra-day and inter-day precisions of this method were 0.2 to 8.9% and 1.3 to 9.1%, respectively. The proposed method was applied to the analysis of four types of Flos Chrysanthemi (Chuju, Boju, Hangju, and Gongju). A total of 60 aglycon moieties of interest were identified in the four types of Flos Chrysanthemi. These aglycones mainly consisted of aliphatic, aromatic, monoterpene, C13-norisoprenoids, and miscellaneous compounds.

Open access
Acta Chromatographica
Authors: D. Trbović, T. Polak, L. Demšar, N. Parunović, M. Dimitrijević, D. Nikolić and V. Đorđević

With the aim to reinforce laboratory competence in the field of testing the quality of fish from aquaculture, a study on the precision of fatty acid (FA) analyses in fish meat and fish feed was undertaken. Different methods were performed in laboratories. In situ transesterification method and extraction of lipids from the fish were followed by capillary gas chromatography with flame ionization detection. The reproducibility (R) values of the majority of FAs were less than 3% of their absolute values. Differences in calculating ionization detector response factors and/or autoxidation caused by faulty sample-handling could lead to variation in quantification of FAs in fish, especially for FA C22:6n-3. Statistical analysis showed a significant correlation between the two laboratories' quantifications of FAs in fish and fish feed (Pearson's correlation coefficient; r = 0.987, r = 0.994, and r = 0.997; for fish Z [trout], fish Š [rainbow trout], and fish feed, respectively). Overall, adequate accuracy was obtained in this study. The proposed method provides a fast and efficient means of identifying fish and feed for quality control purposes.

Open access

A simple, rapid, and sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed and validated for the determination of zinc pyrithione (ZnPT) and pyrithione (PT) in shampoos. The method consisted of a liquid–liquid extraction for sample preparation. The mass spectrometer was operated in multiple reaction monitoring (MRM) mode via the positive electrospray ionization interface. A linear regression (weighted 1/x) was used to fit calibration curves over the concentration range of 50–2000 ng/mL for both ZnPT and PT. Excellent linearity (r 2 ≥ 0.9996) was achieved for all. The method was validated and found to be accurate (95.9–108.2% for ZnPT and 94.9–110.4% for PT), precise, and selective. Analytes in shampoos were found to be stable in the autosampler (6 °C for 6 h), in room temperature (for 6 h), and after three freeze–thaw cycles, and recovery of analytes was reproducible (90.8–94.6% for ZnPT and 90.2–96.3% for PT).

Open access

In this research, a novel method was developed for the matrix solid phase dispersion (MSPD) followed by high-performance liquid chromatography (HPLC) quantification of four marker constituents (vitamin C, gallic acid, rutin, and ellagic acid) in the freeze-dried pomegranate fruit juice. Various MSPD parameters like type of dispersant, sample–dispersant ratio, solvents, its volume, and time of extraction have been optimized after many trials. Furthermore, HPLC method has been developed and optimized for the analysis of all four components. The HPLC separation was achieved using a 250 × 4.6 mm column, particle size of 5 μm, C18 reverse phase column, with a mobile phase consisting of acetonitrile and 0.05% H3PO4, in gradient elution mode with a mobile phase flow rate of 1 mL/min, using ultraviolet (UV)–visible detection at 254 nm. All calibration curves showed good linear regression (r 2 ≥ 0.9925) within test ranges. The extraction recoveries of the marker constituents analyzed by MSPD methods were found as ranging from 97.5% to 103.5%. From comparing the chromatograms, validation data and other parameters like time, labor, and feasibility, we found that MSPD technique was most suitable for the analysis as compared to conventional liquid–liquid extraction technique.

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We have developed a strategy to analyze the components absorbed in the plasma and brain tissue of rats after intragastric administration of Terminalia chebula Retz extracts by ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UPLC–QTOF-MS). Nine components (gallic acid, methyl gallate, ferulic acid, ethyl gallate, brevifolin carboxylic acid, ellagic acid, galloflavin, arjugenin, and arjunic acid) and four metabolites were identified in plasma, and five components (ethyl gallate, brevifolin carboxylic acid, ellagic acid, arjugenin, and arjunic acid) were identified in the rat brain based on their fragmentation behaviors. The components present in the plasma were associated with the antioxidant activity of T. chebula Retz, and the components absorbed in the brain were associated with its neuro-protective effects. This approach allowed us to rapidly determine the active components of T. chebula Retz and develop a method for its quality control. This analysis method showed good resolution and high sensitivity, and is a potentially powerful tool for the determination of effective components of natural products.

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Krebs buffer is considered one of the most used physiological buffers in biomedical research. In the current work, a rapid reversed-phase high-performance liquid chromatographic (RP-HPLC) method with ultraviolet (UV) detection at 214 nm was developed and validated according to European Medicines Evaluation Agency (EMEA) guidelines for the determination and quantification of propranolol in Sprague–Dawley rat's serum and in Krebs buffer. This method can be applied for both in vivo and in vitro studies with short run time of 7.0 min . Isocratic elution with a flow rate of 1.0 mL/min was employed. BDS Hypersil C-18 column (150 mm × 4.6 mm and 5 μm) was used to obtain satisfactory resolution. The mobile phase used contained a mixture of acetonitrile, methanol, and triethylammonium phosphate solution (15.0:32.5:52.5, v/v). Best separation between propranolol and the internal standard (I. S.) sildenafil was obtained at 4.2 and 5.5 min, respectively. Propranolol was linear over a concentration range of 50.00–3000 ng/mL with acceptable accuracy, and intra- and inter-day precision. Dilution integrity was assessed and was found to be within the acceptable range for both serum and Krebs buffer. Sample stability tests were studied at different storage conditions, and all the analytes were found to be stable. The mean percentage of recovery of propranolol was found to be 97.06% and 98.57% for serum and Krebs buffer, respectively.

Open access

A reliable and rapid high-performance liquid chromatography coupled with diode array detector method (HPLC–DAD) was established and validated to determine eight gingerol simultaneously in the rhizomes of Zingiber offcinale Rosc. The separation of eight compounds (4-hydroxy-3-methoxy-benzenebutanol,3,5-dihydroxy-1-(4-hydroxy-3-methoxyphenyl) decane, 3,5-dihydroxy-1-(3,4-dimethoxyphenyl) decane, 6-gingerol, 8-gingerol, 6-shogaol, 5-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-1,4-decadien-3-one, and 10-gingerol) were performed on an Agilent TC(2) C18 (250 mm × 4.6 mm, 5 μm) at 30 °C using acetonitrile (A) and 1% formic acid aqueous solution (B) as the mobile phase with gradient elution (0–10 min, 20%–35% A; 10–28 min, 35%–55% A; 28–35 min, 55%–60% A; 35–55 min, 60%–70% A; 55.01–60 min, 100%–100% A). The detection wavelength was set at 280 nm, and the flow rate was 0.8 mL/min. Validation of the analytical method was performed by linearity, precision, and accuracy test. All compounds were quantified with good linear calibration curves (coefficient of determination R 2, >0.9999). The method showed good precision with overall coefficients of variation between 0.56% and 0.84%. The range of recovery was from 95.50% to 104.14% for the analytes. This method was successfully applied to quantify eight gingerols in Z. offcinale Rosc from different regions in China, so it can provide quality assessment for this medicine.

Open access

An effective, reliable, and sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) with diode array detector (DAD) method was investigated for simultaneous determination of polydatin, isoquercitrin, resveratrol, and nicotiflorin in Tetrastigma hemsleyanum. The chromatographic separation of the four compounds was carried out on a Welchrom ODS column (4.6 mm × 250 mm, 5 μm) by gradient elution with phosphoric acid (H3PO4) aqueous solution (0.4%)–methanol as the mobile phase, at the temperature of 30 °C and a flow rate of 1.0 mL/min. The detection wavelength was set at 270 nm. Under optimum conditions, the baseline separation of these four compounds can be performed within 30 min. The developed method was validated in terms of detection limit, quantification limit, linearity, precision, and recovery tests. Eventually, the established HPLC–DAD method was successfully applied to the simultaneous determination of polydatin, isoquercitrin, resveratrol, and nicotiflorin in the extract of herb T. hemsleyanum.

Open access

The objective of the current research is to understand the degradation behavior of avanafil under different stress conditions and to develop a stability-indicating high-performance liquid chromatography (HPLC) method for simultaneous determination of degradants observed during degradation. Avanafil tablets were exposed to acid, base, water, oxidative, thermal, and photolytic degradation conditions. In acid, oxidative, thermal, and humidity degradation, significant degradation was observed. All the degradants observed during degradation were separated from known impurities of avanafil by using reverse-phase (RP)-HPLC. Mobile phase A, 0.1% trifluoro acetic acid and triethylamine in water, and mobile phase B, water and acetonitrile in the ratio of 20:80 (v/v), were used at a flow rate of 1.2 mL/min in gradient elution mode. Separation was achieved by using Inertsil ODS 3 column (3 μm, 4.6 mm × 250 mm) at 45 °C. Peak responses were recorded at 245 nm. Method capability for detecting and quantifying the degradants, which can form during stability, was proved by demonstrating the peak purity of avanafil peak in all the stressed samples. Mass balance was established by performing the assay of stressed sample against reference standard. Mass balance was found >97% for all the stress conditions. The developed analytical method was validated as per International Conference on Harmonization (ICH) guidelines. The method was found specific, linear, accurate, precise, rugged, and robust.

Open access

Elsholtzia densa Benth. var. densa (Lamiaceae) is a famous medicinal herb which has been widely used for treatment of colds, headaches, pharyngitis, fever, diarrhea, digestion disorder, rheumatic arthritis, nephritises, and nyctalopia in China. In this study, fraction of the ethyl alcohol extract of E. densa (aerial part) by different polarity solvents indicated that the ethyl acetate soluble fraction exhibited a potent 1,1-diphenyl-2-picryhydrazyl (DPPH) radical scavenging activity with the IC50 value of 148.2 μg/mL. Under the target guidance of DPPH experiment, isoquercitrin, trachelogenin, ethyl caffeate, and arctigenin were separated with purities 95.98%, 92.98%, 96.07%, and 88.83%, respectively, by a dual-mode high-speed counter-current chromatography (HSCCC) method using n-hexane–ethyl acetate–methanol–water (4.5:5:3:4, v/v/v/v) as the solvent system. In order to evaluate the scientific basis, antioxidant activity of four isolated compounds was assessed by the radical scavenging effect on DPPH radical; isoquercitrin and ethyl caffeate showed stronger antioxidant activities with IC50 values of 9.4 μg/mL and 9.2 μg/mL, respectively, while trachelogenin and arctigenin showed weak antioxidant activities with IC50 values of >500 μg/mL and 72.8 μg/mL, respectively. Results of the present study indicated that the combinative method using DPPH antioxidant assay and dual-mode HSCCC could be widely applied for rapid screening and isolating of antioxidants from complex traditional Chinese medicine extract.

Open access
Acta Chromatographica
Authors: Peiwu Geng, Jing Zhang, Bingbao Chen, Qianqian Wang, Shuanghu Wang and Congcong Wen

Dauricine is the major bioactive component isolated from the roots of Menispermum dauricum D.C., a bisbenzylisoquinoline alkaloid derivative, and has shown multiple pharmacological properties. In this work, a sensitive and selective ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method was developed for determination of dauricine in rat plasma and its application to pharmacokinetic study of dauricine after intravenous and oral administration in rats. After addition of daurisoline as an internal standard (IS), protein precipitation by acetonitrile was used to prepare samples. Chromatographic separation was achieved on a UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) with 0.1% formic acid and acetonitrile as the mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; multiple reactions monitoring (MRM) mode was used for quantification. Calibration plots were linear throughout the range 2–600 ng mL−1 for dauricine in rat plasma. Relative standard deviation (RSD) of intra-day and inter-day precision was less than 13%. The accuracy of the method was between 95.8% and 105.9%. Matrix effect of dauricine in rat plasma ranged from 88.0% to 90.3%. Mean recoveries of dauricine in rat plasma ranged from 91.5% to 95.1%. The method was successfully applied to pharmacokinetic study of dauricine after intravenous and oral administration in rats. The bioavailability of dauricine was found to be 55.4% for the first time.

Open access
Acta Chromatographica
Authors: Yunfang Zhou, Bingbao Chen, Junyan Chen, Yanwen Dong, Shuanghu Wang, Congcong Wen, Xianqin Wang and Xiaomin Yu